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Venturi effect

The Venturi effect is a fundamental principle in fluid dynamics describing the reduction in static pressure that occurs when a fluid flows through a constricted section of a pipe or tube, causing the fluid's velocity to increase due to the conservation of mass and energy.^[1] This phenomenon arises from Bernoulli's principle, which posits that in an incompressible, inviscid fluid flow along a streamline, an increase in velocity corresponds to a decrease in pressure, maintaining constant total mechanical energy.^[2] The effect is observable in both liquids and gases under subsonic conditions and forms the basis for various measurement and operational devices in engineering.^[3] Named after Italian physicist Giovanni Battista Venturi, who first documented the behavior in 1797 through experiments on water flow in short cylindrical tubes, the principle was initially explored in the context of hydraulic systems but gained broader recognition in the 19th century.^[4] Venturi's observations highlighted how constriction alters flow characteristics without external energy input, laying groundwork for later theoretical refinements tied to Bernoulli's equation from 1738.^[5] Practical implementations, such as the Venturi tube for flow metering, emerged in the 1880s, enabling precise quantification of fluid rates by measuring pressure differentials across the constriction.^[6] The Venturi effect has extensive applications across industries, including flow measurement in pipelines where pressure drops are calibrated to determine volume or mass flow rates with high accuracy.^[7] In automotive engineering, it facilitates fuel-air mixing in carburetors by drawing fuel into the airstream via the low-pressure zone.^[8] Additional uses encompass aspirators for creating vacuums in laboratories, atomizers for spray generation in medical and agricultural devices, and entrainment systems in chemical processing to mix fluids efficiently.^[6] Its principles also influence designs in aquariums for aeration and in aerospace for wind tunnel testing, underscoring its versatility in optimizing fluid handling.^[1]

Definition and History

Basic Principle

The Venturi effect refers to the reduction in static pressure that occurs when a fluid flows through a constriction in a pipe or tube, causing the fluid's velocity to increase while its total energy remains conserved.^[9] This phenomenon arises from the principle of conservation of mass, which dictates that the volumetric flow rate of an incompressible fluid must remain constant throughout the system.^[10] In a typical flow scenario, the fluid enters a wider section of the conduit at a relatively low velocity and higher pressure. As it approaches the narrower constriction, the continuity of flow requires the fluid to accelerate to maintain the same mass flow rate, converting potential energy associated with pressure into kinetic energy. This acceleration results in a measurable drop in static pressure at the constricted point, as the faster-moving fluid exerts less force perpendicular to the flow direction. The effect is a direct consequence of energy conservation in steady, inviscid flow, briefly aligning with Bernoulli's principle that relates pressure and velocity inversely.^[11]^[12] The standard configuration for observing the Venturi effect involves a tube with a wide inlet section that gradually converges to a narrow throat, where the velocity peaks and pressure is minimized, followed by a diverging recovery section that allows the flow to slow down and pressure to partially recover. This setup ensures smooth transitions to minimize turbulence and energy losses, highlighting the effect's reliance on controlled geometric changes in the conduit.^[10]^[9]

Historical Development

The foundations of the Venturi effect trace back to the 18th century, with early insights into the relationship between fluid velocity and pressure provided by Daniel Bernoulli in his seminal 1738 work Hydrodynamica. In this text, Bernoulli described how the pressure in a moving fluid decreases as its velocity increases, laying the groundwork for later observations of constriction-induced flow acceleration.^[13]^[14] The effect itself is attributed to Italian physicist Giovanni Battista Venturi, who systematically investigated and documented the phenomenon in 1797 through experiments detailed in his publication Recherches expérimentales sur le principe de la communication latérale du mouvement dans les fluides. Venturi's work demonstrated how fluid speed increases and pressure drops in a narrowing conduit, using setups involving water flow through short cylindrical tubes to observe lateral pressure transmission. This marked the first explicit recognition of the effect, though it built directly on Bernoulli's principles without introducing new theoretical frameworks.^[15]^[16] Advancements in the 19th century focused on practical applications, notably with American hydraulic engineer Clemens Herschel's invention of the Venturi meter in 1887. Herschel adapted Venturi's observations to create a device for accurately measuring water flow rates in large pipes, as outlined in his treatise The Venturi Meter: An Instrument Making Use of a New Method of Gauging Water. This innovation facilitated widespread adoption in water management systems, such as those in Holyoke, Massachusetts. By the early 20th century, the Venturi meter's design had been standardized in engineering practices, with organizations like the International Organization for Standardization (ISO) and the American Society of Mechanical Engineers (ASME) incorporating specifications for its geometry and calibration in documents such as ISO 5167-4 and ASME MFC-3M.^[17] In the 21st century, the Venturi effect has remained a cornerstone of fluid dynamics without significant theoretical revisions since the mid-20th century, continuing to feature prominently in educational texts and engineering curricula. Its relevance has grown in computational contexts, particularly through computational fluid dynamics (CFD) simulations exploring associated phenomena like cavitation in constricted flows, as evidenced by studies in the 2020s that model bubble formation and collapse in Venturi geometries under varying pressures.^[18]^[19]

Theoretical Foundation

Bernoulli's Principle

Bernoulli's principle states that, for an incompressible and inviscid fluid in steady flow, the total mechanical energy—comprising pressure energy, kinetic energy, and potential energy—remains constant along a streamline. This conservation law implies that an increase in the fluid's velocity at one point along the streamline is accompanied by a corresponding decrease in static pressure or potential energy, or both, to maintain the overall energy balance. Originally formulated by Daniel Bernoulli in his 1738 work Hydrodynamica, the principle provides the theoretical basis for understanding pressure-velocity relationships in fluid dynamics.^[20]^[21] The principle is mathematically expressed through Bernoulli's equation, which balances the key energy components per unit volume: static pressure P, velocity head represented by the kinetic energy term \frac{1}{2}\rho v^2 (where \rho is fluid density and v is velocity), and elevation head \rho g h (where g is gravitational acceleration and h is height above a reference level). These terms sum to a constant total head along the streamline:

P + \frac{1}{2}\rho v^2 + \rho g h = \text{constant}

In head form, often used for engineering applications, the equation divides by \rho g to yield pressure head P/(\rho g), velocity head v^2/(2g), and elevation head h, emphasizing the equivalence of these forms of energy in terms of height. This formulation highlights how energy conversions occur without loss in ideal conditions.^[22]^[23]^[24] The principle relies on several assumptions: the flow must be steady, meaning fluid properties do not vary with time at any point; the fluid is incompressible, so density \rho remains constant; and the flow is inviscid, neglecting frictional losses from viscosity. These idealizations simplify analysis but introduce limitations in real-world scenarios, where viscosity can cause energy dissipation and deviations from the predicted constant total head, particularly in high-speed or turbulent flows. Despite these constraints, the principle holds well for low-viscosity fluids like air or water at subsonic speeds.^[25]^[26]^[21] In the context of the Venturi effect, Bernoulli's principle explains the observed pressure drop as fluid velocity increases through a constriction: the rise in kinetic energy (higher v) must be offset by a reduction in static pressure P to preserve the constant total mechanical energy along the streamline. This inverse relationship between velocity and pressure is fundamental to devices exploiting the effect, though real applications account for minor viscous losses not captured by the ideal model.^[24]^[27]^[22]

Mathematical Derivation

The mathematical derivation of the Venturi effect begins with the continuity equation, which stems from the principle of mass conservation in fluid flow. For steady, incompressible flow through a conduit with varying cross-sectional area, the mass flow rate entering a section must equal the mass flow rate exiting it. Considering a control volume between two points 1 and 2, the rate of mass inflow is \rho A_1 v_1 and outflow is \rho A_2 v_2, where \rho is the fluid density, A is the cross-sectional area, and v is the average velocity normal to the area. With no accumulation of mass in steady flow, \rho A_1 v_1 = \rho A_2 v_2. For incompressible fluids, \rho is constant, yielding the simplified form:

A_1 v_1 = A_2 v_2

This relation implies that velocity increases as the cross-sectional area decreases, such as in the constricted throat of a Venturi tube.^[28] To relate pressure and velocity changes, Bernoulli's equation is applied, derived from energy conservation along a streamline for steady, inviscid, incompressible flow without shaft work. The equation states that the sum of pressure, kinetic, and potential energies per unit volume is constant:

P_1 + \frac{1}{2} \rho v_1^2 + \rho g h_1 = P_2 + \frac{1}{2} \rho v_2^2 + \rho g h_2

where P is static pressure, g is gravitational acceleration, and h is elevation. In a typical horizontal Venturi tube, the elevation difference is negligible (h_1 \approx h_2), simplifying to:

P_1 + \frac{1}{2} \rho v_1^2 = P_2 + \frac{1}{2} \rho v_2^2

Rearranging gives the pressure difference:

\Delta P = P_1 - P_2 = \frac{1}{2} \rho (v_2^2 - v_1^2)

Substituting v_2 = \frac{A_1}{A_2} v_1 from the continuity equation yields:

\Delta P = \frac{1}{2} \rho v_1^2 \left[ \left( \frac{A_1}{A_2} \right)^2 - 1 \right]

This demonstrates the inverse relationship between pressure and velocity squared in the Venturi effect.^[29]^[30] In practice, real fluids exhibit viscous losses and flow imperfections, deviating from ideal predictions. To account for these, a discharge coefficient C_d is introduced in flow rate calculations derived from the above equations, where C_d represents the ratio of actual to ideal mass flow rate. For classical Venturi tubes, C_d typically ranges from 0.95 to 0.99, depending on design and Reynolds number.^[31]

Flow Phenomena

Choked Flow

Choked flow represents a limiting condition in Venturi devices handling compressible fluids, such as gases, where the flow velocity at the throat reaches the local speed of sound, rendering the mass flow rate independent of any further reduction in downstream pressure.^[32] This phenomenon arises due to the compressibility of the fluid, contrasting with incompressible flows where velocity scales inversely with area per the continuity equation.^[33] In practice, choked flow occurs when the pressure ratio between the throat and inlet, P_{\text{throat}} / P_{\text{inlet}}, drops below a critical threshold of approximately 0.528 for an ideal diatomic gas with specific heat ratio \gamma = 1.4.^[34] At critical conditions, the Mach number at the throat equals 1, marking the transition to sonic flow.^[32] For isentropic flow, the choked mass flow rate \dot{m} through the throat area A_{\text{th}} is determined solely by upstream stagnation conditions and given by

\dot{m} = A_{\text{th}} \, P_0 \, \sqrt{ \frac{\gamma}{R T_0} } \, \left( \frac{2}{\gamma + 1} \right)^{ \frac{\gamma + 1}{2(\gamma - 1)} }

where P_0 and T_0 are the inlet stagnation pressure and temperature, \gamma is the specific heat ratio, and R is the gas constant.^[32] This equation derives from combining the continuity, energy, and isentropic relations, highlighting how upstream pressure and temperature govern the flow once sonic conditions are met.^[35] The effects of choked flow include a fixed mass flow rate that varies only with upstream parameters, while downstream pressure changes have no influence beyond establishing the choked state.^[36] If the downstream pressure is sufficiently low to cause over-expansion, oblique or normal shock waves can form in the diverging section of the Venturi, leading to flow separation and reduced pressure recovery efficiency.^[37] In Venturi applications, such as nozzles for gas flow measurement or propulsion systems, choked flow imposes operational limits, particularly in high-speed scenarios where maintaining subsonic throat conditions is challenging.^[38]

Flow Expansion

In the diverging section, also known as the diffuser, of a Venturi device, the fluid flow decelerates as the cross-sectional area gradually increases, enabling the conversion of kinetic energy back into static pressure energy. This recovery process follows from the application of Bernoulli's principle in subsonic flows, where the velocity reduction after the throat leads to a rise in pressure toward the inlet value. In well-designed Venturi tubes, this pressure recovery can reach 80-90% of the differential pressure drop observed across the throat, minimizing overall energy dissipation compared to other flow constriction devices.^[39]^[40] Key design considerations for the diverging section focus on optimizing the divergence angle to balance recovery efficiency and flow stability. Optimal half-angles typically range from 5° to 15°, as angles within this range minimize energy losses while accommodating practical length constraints; for instance, angles around 5° are preferred for high aspect ratio diffusers to achieve near-ideal performance. Exceeding these limits introduces a strong adverse pressure gradient, which decelerates the near-wall flow and promotes boundary layer separation, leading to recirculation zones, increased turbulence, and reduced pressure recovery.^[41]^[42]^[43] Energy losses in the diverging section arise primarily from viscous friction along the walls and turbulence generated by shear layers, rendering the pressure recovery process irreversible and less than ideal. These losses are characterized by the pressure recovery coefficient C_p, defined as

C_p = \frac{P_{\text{exit}} - P_{\text{throat}}}{P_{\text{inlet}} - P_{\text{throat}}}

where P_{\text{exit}}, P_{\text{throat}}, and P_{\text{inlet}} denote the static pressures at the diffuser exit, throat, and inlet, respectively. Values of C_p typically fall between 0.80 and 0.95 for efficient subsonic Venturi diffusers, reflecting the fraction of available pressure rise that is actually achieved.^[44]^[45]

Apparatus and Devices

Venturi Tubes

A Venturi tube is a device featuring a streamlined, converging-diverging geometry designed to measure fluid flow by exploiting pressure differences. The converging inlet section has an included angle of 21° ± 1°, accelerating the fluid toward the cylindrical throat, where the cross-sectional area is minimized. The throat maintains a constant diameter, with the beta ratio β—defined as the throat diameter divided by the inlet diameter—ranging from 0.3 to 0.75 for optimal performance across various pipe sizes, depending on fabrication method (e.g., 0.4 to 0.75 for machined).^[46] The diverging outlet section follows with an angle of 7° to 15° (recommended 7° to 8°), aiding in the gradual deceleration of the flow. These geometric parameters, along with precise tolerances such as ±0.1% on throat diameter, are standardized in ISO 5167-4:2022 to ensure accuracy and repeatability in installation.^[46] Construction of Venturi tubes adheres to ISO 5167-4:2022 standards for dimensions, which specify pipe diameters from 50 mm to 1200 mm depending on the fabrication method (machined, cast, or welded). The 2022 edition includes refinements to discharge coefficients and installation effects for improved uncertainty. Materials are selected based on fluid compatibility and durability, commonly including brass for corrosion resistance in water applications, stainless steel (such as grades 304 or 316) for harsh industrial environments, and plastics like PVC for cost-effective, non-corrosive setups. Fabrication techniques ensure smooth internal surfaces to minimize turbulence, with machined versions offering the tightest tolerances for smaller diameters and rough-welded plates suited for larger, high-pressure conduits.^[46]^[47] In operation, fluid entering the Venturi tube accelerates through the converging inlet, achieving peak velocity and minimum pressure at the throat, which generates a measurable differential pressure ΔP between the inlet and throat taps. This design inherently promotes pressure recovery in the diverging section through flow expansion, yielding a low permanent pressure loss of 10% to 20% of ΔP. The first practical Venturi tube was developed by Clemens Herschel in 1887 as a water meter for large-scale gauging in municipal systems. In modern applications during the 2020s, computational fluid dynamics (CFD) simulations validate and optimize these designs, enhancing precision for flow metering in industries like wastewater treatment and chemical processing.^[48]^[49]^[50]

Orifice Plates and Variants

An orifice plate is a thin, flat device typically made of stainless steel or other corrosion-resistant materials, featuring a precisely machined hole that creates a restriction in a pipe to induce a pressure differential for flow measurement. The plate is inserted between pipe flanges, with the hole's diameter (d_orifice) relative to the pipe diameter (d_pipe) defined by the beta ratio β = d_orifice / d_pipe, commonly ranging from 0.2 to 0.8 to balance sensitivity and durability. Unlike gradual constrictions, orifice plates lack a downstream recovery section, leading to abrupt flow acceleration and higher energy dissipation.^[51]^[52] Several variants adapt the basic design for challenging fluids. The eccentric orifice plate offsets the hole from the pipe's center to prevent solids accumulation in the lower portion, making it suitable for dirty or viscous fluids like slurries. Segmental orifice plates feature a D-shaped opening that spans part of the pipe diameter, ideal for handling slurries or flows with high solids content by allowing debris to pass through the unobstructed segment. Conical orifice plates incorporate a tapered entrance for a more gradual restriction, reducing turbulence in applications with varying flow conditions.^[53]^[54]^[55] In terms of performance, orifice plates generate a significant differential pressure (ΔP) across the restriction, with permanent pressure losses often reaching 60-80% of the total ΔP due to the lack of flow recovery, though this simplicity makes them more cost-effective than alternatives. The discharge coefficient C_d, which accounts for flow contraction and friction, typically averages around 0.6 for standard designs but varies with the Reynolds number (Re), decreasing at low Re due to increased viscous effects and stabilizing above Re ≈ 10^4.^[56]^[57]^[58] Orifice plates are widely used in the oil and gas industry for custody transfer metering, where accurate volumetric flow determination during ownership changes requires standardized, low-maintenance devices compliant with API and ISO standards. Recent studies from 2023-2025 have explored hybrid Venturi-orifice configurations to improve accuracy in multiphase flows, combining the abrupt restriction of an orifice with Venturi-like recovery to better handle gas-liquid mixtures in subsea or pipeline applications.^[59]^[60]^[61]^[62]

Measurement Techniques

Flow Rate Determination

The Venturi effect enables the determination of volumetric flow rate Q in a conduit by measuring the pressure difference \Delta P between the upstream section and the throat of a Venturi tube, leveraging the principles of mass continuity and Bernoulli's equation. The standard formula for incompressible fluids, such as liquids, is derived by combining the continuity equation A_1 v_1 = A_2 v_2 (where A is cross-sectional area and v is velocity) with Bernoulli's relation P_1 + \frac{1}{2} \rho v_1^2 = P_2 + \frac{1}{2} \rho v_2^2 (assuming negligible elevation change and steady flow), yielding:

Q = C_d \frac{A_2}{\sqrt{1 - \beta^4}} \sqrt{\frac{2 \Delta P}{\rho}}

Here, C_d is the discharge coefficient (typically 0.95–0.99 for well-designed Venturi tubes), A_2 is the throat area in square meters, \beta = d/D is the diameter ratio (throat diameter d over pipe diameter D), \Delta P is in pascals, and \rho is fluid density in kg/m³; the result Q is in m³/s.^[51]^[63] For mass flow rate \dot{m}, the volumetric rate is multiplied by density: \dot{m} = \rho Q, providing output in kg/s. In compressible flows, such as gases, the formula incorporates an expansion factor Y (accounting for density variation across the meter, typically 0.96–1.00) and uses a compressibility factor Z (from the ideal gas law modification \rho = P M / (Z R T), where P is pressure, M molecular weight, R gas constant, and T temperature) to adjust density, yielding \dot{m} = Y C_d \frac{\pi d^2}{4 \sqrt{1 - \beta^4}} \sqrt{2 \rho_1 \Delta P}, with \rho_1 as upstream density.^[64] Calibration of Venturi meters follows ISO 5167-4 (2022 edition) standards, which specify \beta ratios of 0.3–0.75 and provide tabulated C_d values based on geometry, surface roughness, and Reynolds number Re_D = \rho v D / \mu (where \mu is dynamic viscosity); uncalibrated meters achieve accuracies of ±1% for liquids and ±2% for gases within specified ranges.^[64]^[65]^[46] These relations hold for turbulent flows with pipe Reynolds numbers Re_D > 2 \times 10^5, ensuring the discharge coefficient remains constant; below this threshold, viscous effects increase uncertainty. For multiphase flows like oil-water mixtures, standard single-phase models underperform due to phase interactions, but recent computational fluid dynamics (CFD) studies have improved predictions by incorporating two-phase models, particularly in stratified regimes.^[64]^[66]

Pressure Measurement

Pressure measurement in Venturi effect applications relies on capturing the differential pressure (ΔP) between the inlet and throat sections of the flow constriction. Traditional methods include manometers, which provide direct visual indication of pressure differences. U-tube manometers, consisting of a U-shaped tube partially filled with liquid, measure higher ΔP values by observing the height difference in the liquid columns connected to the pressure taps, offering simplicity and no need for power.^[67] For lower ΔP, typically below 10 inches of water column, inclined manometers are preferred; their slanted tube design amplifies small pressure changes along the inclined path, improving readability and precision for subtle Venturi-induced drops.^[68] Electronic methods dominate modern setups, using differential pressure transducers for automated and remote readings. Piezoresistive transducers employ a diaphragm with embedded strain gauges that change electrical resistance under pressure-induced strain, converting ΔP to a proportional voltage signal with high sensitivity and fast response times.^[69] Capacitive transducers, alternatively, detect ΔP through changes in capacitance between a fixed and movable plate as the diaphragm deflects, providing stable performance in harsh environments and suitability for clean fluids in Venturi systems. These transducers often integrate with the raw ΔP data for subsequent flow rate determination. Installation of pressure taps follows standardized guidelines to ensure reliable ΔP capture. Taps are drilled into the pipe wall at the inlet (one pipe diameter upstream from the convergent section entrance), the throat (at the minimum cross-section plane), and optionally the outlet (in the divergent section for pressure recovery assessment), using pipe wall tappings, often interconnected by annular chambers to average pressure and minimize errors from flow disturbances.^[70] These locations adhere to ISO 5167-4 specifications for Venturi tubes, which mandate separate pipe wall tappings interconnected by annular chambers to average pressure and minimize errors from flow disturbances. Accuracy in pressure measurement is influenced by factors such as dynamic response in non-steady flows. In pulsating flows, common in reciprocating pumps, transducers must exhibit adequate bandwidth to capture rapid pressure fluctuations without attenuation, as slow response can lead to underestimation of mean ΔP by up to 20% in high-frequency pulsations.^[71] Digital integration with supervisory control and data acquisition (SCADA) systems enhances accuracy by enabling real-time signal processing, filtering, and calibration adjustments directly from central control rooms.^[72] Advancements in the 2020s have introduced wireless differential pressure sensors and IoT-enabled devices for seamless real-time monitoring in pipeline applications. These battery-powered or energy-harvesting transmitters, such as piezoresistive wireless units, transmit ΔP data via protocols like WirelessHART or LoRaWAN to cloud platforms, reducing wiring costs and enabling predictive maintenance in remote Venturi installations.^[73] IoT integration allows for continuous data logging and anomaly detection, with systems achieving sub-1% accuracy in dynamic pipeline environments through edge computing.^[74]

Condition Compensations

In Venturi flow measurements, density variations due to temperature changes must be compensated, particularly for liquids where thermal expansion alters the fluid's volume. For liquids, the density ρ at temperature T is corrected using the relation ρ = ρ₀ / (1 + α (T - T₀)), where ρ₀ is the reference density at T₀ and α is the coefficient of thermal expansion, ensuring accurate volumetric flow calculations by accounting for the fluid's expansion or contraction.^[75] For gases, density is primarily governed by the ideal gas law, ρ = P M / (R T), where P is pressure, M is molar mass, R is the gas constant, and T is absolute temperature; this allows real-time updates to maintain measurement precision under varying conditions.^[76] Real gas deviations are addressed via the compressibility factor Z, incorporated as ρ = P M / (Z R T), with Z calculated using methods like the AGA No. 8 detailed characterization for high-accuracy applications in critical flow venturis.^[76]^[77] Temperature compensation in modern Venturi systems often employs resistance temperature detectors (RTDs) integrated into multivariable transmitters, which automatically adjust flow readings by sensing local fluid temperature and applying corrections to density and differential pressure signals.^[78] Pressure variations also influence compensation, notably in establishing choked flow thresholds, where the critical pressure ratio (throat to upstream inlet) determines the onset of sonic velocity at the throat, requiring adjustments to avoid underestimating maximum flow rates.^[37] To distinguish mass flow rate ṁ from volumetric flow rate Q, the conversion ṁ = ρ Q is applied, with dynamic updates to ρ based on ongoing temperature and pressure measurements for consistent mass-based outputs in processes like custody transfer.^[79] Viscosity effects are compensated through adjustments to the discharge coefficient C_d, which depends on the Reynolds number Re; for Venturi tubes, C_d remains nearly constant above Re ≈ 2 × 10⁵ but decreases at lower Re due to increased viscous losses, necessitating empirical corrections per ISO 5167 standards.^[80] Recent advancements from 2022 to 2025 incorporate AI-based compensations, particularly data-driven machine learning models for turbulent or multiphase flows in Venturi tubes, improving accuracy over traditional methods by predicting flow regime variations from real-time sensor data.^[81]

Applications

Engineering and Industrial Uses

The Venturi effect is widely applied in flow metering for industrial processes, particularly in water treatment plants and oil and gas pipelines, where it enables accurate measurement of fluid flow rates based on pressure differentials across a constricted tube. In wastewater treatment, Venturi meters have been used for over a century to monitor incoming sewage, treated effluent, and chemical dosing flows, offering high accuracy and minimal pressure loss suitable for large-scale operations. In offshore oil and gas transportation, Venturi meters facilitate multi-phase flow metering of oil, gas, and water without phase separation, supporting volumetric flow calculations essential for custody transfer and allocation. These devices are commonly integrated with differential pressure transmitters to determine flow rates, providing reliable data for process control and regulatory compliance. In mixing devices, the Venturi effect drives efficient fluid entrainment and atomization, as seen in carburetors, ejectors, and fuel injectors. Carburetors utilize a Venturi constriction to accelerate airflow, creating a low-pressure zone that draws fuel from a nozzle for precise air-fuel mixing in internal combustion engines. Ejectors, also known as Venturi pumps, employ high-velocity motive fluid to generate vacuum and entrain secondary fluids or gases, commonly used in industrial processes for mixing chemicals or creating suction without moving parts. Fuel injectors in some systems leverage the Venturi principle to disperse fuel into high-speed airstreams, enhancing combustion efficiency in engines. Venturi scrubbers apply this effect for pollution control by accelerating contaminated gas through a throat, atomizing scrubbing liquid to capture particulate matter and gases like sulfur dioxide, achieving removal efficiencies over 99% in industrial exhaust streams; the global wet scrubber market, including Venturi types, was valued at USD 1.17 billion in 2024 and is projected to grow at 8.5% CAGR through 2030 due to rising emissions regulations. Jet pumps and aspirators represent key applications in fluid handling, where the Venturi effect allows a high-velocity motive fluid to entrain and pump secondary flows in industrial settings. Jet pumps use compressed motive fluid to create low pressure in the Venturi throat, enabling the transport of liquids or slurries in pipelines without mechanical seals, ideal for oilfield injection or chemical processing. Aspirators, functioning similarly, generate vacuum for pneumatic conveying of powders and granules in lean-phase systems, supporting efficient material transfer in manufacturing and mining operations. Recent developments extend the Venturi effect to advanced engineering contexts, such as microfluidic devices and aviation fuel systems. In lab-on-a-chip platforms, miniaturized Venturi pumps enable precise chemical dosing by leveraging pressure drops for controlled fluid entrainment at microscales, as demonstrated in 2021 studies integrating low-cost Venturi components with 3D-printed peristaltic systems for biomedical applications. In aviation, swirl-Venturi fuel-air mixers optimize lean direct injection in gas turbine combustors, injecting fuel through swirlers into Venturi constrictions to reduce emissions while maintaining efficient mixing, as outlined in NASA design guidelines for low-emission engines.

Architectural and Environmental Uses

In architectural design, the Venturi effect is harnessed to facilitate passive cooling and natural ventilation in buildings, particularly through roof-mounted Venturi stacks or tubes that create low-pressure zones to draw in fresh air and exhaust stale air without mechanical fans. These systems exploit wind flow over constricted openings on rooftops, accelerating airflow and enhancing the stack effect in chimneys or vents, which can reduce indoor temperatures by promoting buoyancy-driven circulation in hot climates. For instance, wind towers incorporating Venturi constrictions have demonstrated improved airflow efficiency, lowering cooling loads in tropical buildings by integrating wetted surfaces for evaporative enhancement.^[82]^[83]^[84] Environmentally, Venturi-based atomizers are widely used in spray systems for irrigation and firefighting, where the effect mixes liquids with air to produce fine mists for efficient distribution. In irrigation, Venturi injectors enable precise dosing of fertilizers into water lines, optimizing nutrient delivery while minimizing energy use and chemical waste through pressure differentials that draw in additives without pumps. For firefighting, Venturi scrubbers generate atomized water sprays that enhance fire suppression by entraining air to create high-velocity mists, improving control in confined spaces. Additionally, Venturi aerators in wastewater treatment systems boost oxygen transfer to microbial processes; recent bench-scale studies show these devices achieving up to 55% higher oxygen transfer coefficients compared to conventional diffusers, particularly with extended throat lengths that promote bubble formation and mixing.^[85]^[86]^[87]^[88] In urban planning, the Venturi effect aids ventilation in traffic tunnels by accelerating airflow through constricted nozzles, which generates suction to exhaust smoke and pollutants during emergencies, thereby improving air quality and safety. This approach leverages Bernoulli's principle to induce fresh air intake, reducing reliance on energy-intensive fans in long underground corridors. For sustainability, Venturi-enhanced wind concentrators in renewable energy systems channel accelerated airflow to turbines, increasing power output from low-speed winds; designs with circumferential structures have shown enhanced energy harvesting densities up to 2850 mW/m².^[89] In low-energy HVAC applications, the effect supports fanless air mixing in ducts, where constrictions create pressure gradients for uniform distribution, minimizing pressure losses and supporting net-zero building goals.^[90]^[91]

Natural and Biological Phenomena

In natural settings, the Venturi effect manifests in river systems where channel narrowings, such as those in rapids, accelerate water flow, reducing pressure and contributing to bank erosion. This phenomenon occurs as water velocity increases through constrictions, creating lower hydrostatic pressure that can draw in sediments and undermine surrounding banks, with maximum erosion typically at the narrowest points.^[92] In avian flight, the Venturi effect aids lift generation through wing slot gaps formed by structures like the alula or emarginated primaries, particularly during low-speed maneuvers or dives. Airflow acceleration through these narrow slots lowers pressure on the upper wing surface, enhancing suction and preventing stall by re-energizing the boundary layer. For instance, in peregrine falcons during high-speed dives, the cupped wing configuration induces a Venturi effect in the slots, contributing to aerodynamic efficiency.^[93] Biologically, the Venturi effect influences blood flow in arteries affected by stenoses, where plaque-induced narrowings cause velocity spikes that reduce downstream pressure and generate turbulent murmurs audible during systole. This pressure drop, explained by hydrodynamic principles, can lead to diagnostic indicators like systolic ejection murmurs and contributes to endothelial stress in cardiovascular pathologies.^[94]^[95] In fish respiration, the Venturi effect assists opercular aspiration by creating suction as water streams past the gill cover margins during swimming. This hydrodynamic facilitation enhances water flow over the gills without excessive energy expenditure, complementing active pumping in species reliant on branchial ventilation.^[96] Medically, the Venturi effect underpins oxygen delivery in Venturi masks, where high-velocity oxygen flow through a nozzle entrains ambient air, achieving precise fractional inspired oxygen concentrations (typically 24-60%) for patients with respiratory conditions like COPD. Recent computational fluid dynamics (CFD) simulations of cardiovascular stenoses have quantified these effects, revealing pressure gradients and shear stresses that exacerbate plaque instability, with models showing significant velocity increases, often exceeding 50%, across 50% stenoses under pulsatile flow.^[97]^[98]

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Venturi Theory | Glenn Research Center - NASA
Sep 9, 2025 · The theory is based on the idea that the airfoil upper surface is shaped to act as a nozzle which accelerates the flow.
[10]
None
### Summary of Venturi Effect Basic Principle
[11]
[PDF] Chapter 4: Principles of Flight - Federal Aviation Administration
A practical application of Bernoulli's Principle is the venturi tube. The venturi tube has an air inlet that narrows to a throat (constricted point) and an ...
[12]
[PDF] L 15 Fluids [4] The Venturi Meter Bernoulli's principle WIND
The ball is rotating clockwise. The layer of air adjacent to the ball is dragged along by the rotation, causing the flow speed to be higher on the top side.
[13]
[PDF] Bernoulli "Hydrodynamics. Hydraulics" - hlevkin
H;·drod;namica, by Daniel Bernoulli, as published by Johann Reinhold. Dulsecker at Strassburg in 1738; ... Daniel's Hydrodynamica was begun in 1729, during ...
[14]
[PDF] A History of Hydrodynamics from the Bernoullis to Prandtl
Daniel Bernoulli's Hydrodynamica of 1738. The principle ... Effects of the velocity dependence of pressure according to Daniel Bernoulli. ([1738] plate).<|separator|>
[15]
Recherches expérimentales sur le principe de la communication ...
Recherches expérimentales sur le principe de la communication latérale du mouvement dans les fluides, appliqué à l'explication de différens phénomènes ...Missing: discovery effect Feu Tuyaux Fonte
[16]
An approach to the Venturi effect by historical instruments - IOPscience
Jan 5, 2021 · In this paper, we discuss an approach to the understanding of the Venturi effect based on the study of historical instruments and on simple experiments.
[17]
The Venturi meter : an instrument making use of a new method of ...
Mar 9, 2007 · The Venturi meter : an instrument making use of a new method of gauging water; applicable to the cases of very large tubes, and of a small value ...
[18]
CFD Turbulence Models Assessment for the Cavitation ... - MDPI
This study investigates cavitation in a rectangular-profile Venturi tube using numerical simulations and four turbulence models.
[19]
Cavitating flow through a Venturi using CFD: effects of inlet and ...
Aug 7, 2025 · The works carried out in this study aimed to get a better understanding of the cavitating flow phenomenon. For this, we have numerically studied ...
[20]
[PDF] Bernoulli's Principle | NASA
Bernoulli asserted in. “Hydrodynamica” that as a fluid moves faster, it produces less pressure, and conversely, slower moving fluids produce greater pressure.
[21]
Daniel Bernoulli: Bernoulli's Principle and Equation - TecQuipment
Feb 8, 2019 · The flow must be steady. (Velocity, pressure and density cannot change at any point). · The flow must be incompressible – even when the pressure ...
[22]
https://phys.libretexts.org/Bookshelves/University_Physics/University_Physics_(OpenStax)/Book%3A_University_Physics_I_-_Mechanics_Sound_Oscillations_and_Waves_(OpenStax)/14%3A_Fluid_Mechanics/14.08%3A_Bernoullis_Equation
[23]
Bernoulli's Equation | Engineering Library
Bernoulli's equation makes it easy to examine how energy transfers take place among elevation head, velocity head, and pressure head. It is possible to examine ...
[24]
Bernoulli's equation (article) | Fluid flow - Khan Academy
Bernoulli's equation describes the conservation of mechanical energy in ideal fluid flow. Explore consequences of Bernoulli's equation, including Torricelli's ...
[25]
Bernoulli's Equation
Therefore, to find the velocity V_e, we need to know the density of air, and the pressure difference (p_0 - p_e).
[26]
Bernoulli's Equation - NASA Glenn Research Center
Along a low speed airfoil, the flow is incompressible and the density remains a constant. Bernoulli's equation then reduces to a simple relation between ...
[27]
Bernoulli Equation and the Venturi Effect - Fluid Handling Pro
The venturi effect and Bernoulli's principle Definition Venturi Principle: Increase in fluid speed results in decrease in internal pressure. Because of its ...
[28]
[PDF] Derivation of the Continuity Equation (Section 9-2, Çengel and ...
Derivation of the Continuity Equation. (Section 9-2, Çengel ... The mass flow rate through each face is equal to ρ times the normal component of velocity.
[29]
[PDF] Chapter 5: Bernoulli's Equation - eCommons
Nov 4, 2022 · Bernoulli's Equation describes fluid flow along a streamline, assuming no shear effects, and is derived by force balance on a fluid particle.Missing: mathematical | Show results with:mathematical
[30]
[PDF] Chapter 28 Fluid Dynamics
Eq. (28.4.9) is known as Bernoulli's Equation. 28.5 Worked Examples: Bernoulli's Equation. Example 28.1 Venturi Meter.Missing: effect | Show results with:effect
[31]
USBR Water Measurement Manual - Chapter 14
The effective discharge coefficient for venturi meters ranges from 0.9 to about unity (Streeter, 1951; American Society of Mechanical Engineers, 1983) with ...
[32]
Mass Flow Choking
The maximum mass flow rate through the system occurs when the flow is choked at the smallest area. This location is called the throat of the nozzle.
[33]
All About Thermofluids.com - 1. What is Choked Flow? - Google Sites
Choked flow is the limiting case of the Venturi effect when the fluid is compressible. It takes place when a flowing fluid at given pressure and temperature ...
[34]
Isentropic Flow Equations
The Mach number M is the ratio of the speed of the flow v to the speed of sound a. Eq #1: M = v / a. The speed of sound, in turn, depends on the density r, ...
[35]
[PDF] Understanding - Choked Flow of Gases - O'Keefe Controls
The phenomenon of “Choked Flow” or “Critical Flow” is an essential part of understanding the way gas flows through an orifice. When a gas is flowing through ...
[36]
[PDF] Understanding Choked Flow in Fisher™ Valves
Choked flow is defined as the point at which increasing the pressure drop (AP), while maintaining a constant inlet pressure (P1), yields no further increase in ...
[37]
The Choking Pressure Ratio of a Critical Flow Venturi
The performance of the venturi may be characterized by the ratio of outlet static pressure to inlet total pressure just sufficiently small to produce critical ...
[38]
[PDF] An Introduction to Sonic Nozzles and ISO 9300 - MetHyInfra
meaning that under choked flow conditions, pressure at the throat is approximately 53% of inlet pressure. However, the nozzle diffuser allows pressure recovery ...<|control11|><|separator|>
[39]
Method and apparatus for controlling the flow of fluids into wellbore ...
Oct 6, 2015 · ... Venturi) to create a desired flow characteristic. BACKGROUND ... Pressure recovery in a divergent flowpath is 80% to 90%, relative to ...
[40]
Venturimeter - Fluid Mechanics Lab
d) Diverging section: This is a section in which there is a change of stream area back to the entrance area. The recovery of kinetic energy by its conversion to ...
[41]
Optimum angles of non-standard diffusers and reducers for ...
Oct 3, 2019 · Especially, the optimum angle of a diffuser converged to about 5° when the aspect ratio is over 10. Furthermore, these results were verified ...
[42]
Boundary Layer Theory
In a Venturi meter it has been found that an angle of about 6 provides the optimum balance between length of meter and danger of boundary layer separation which ...
[43]
The hydrodynamics of ejector-Venturi scrubbers and their modelling ...
The thickness of boundary layer grows rapidly due to the existence of adverse pressure gradient in the divergent section, which results in an increase of ...
[44]
Pressure Recovery Coefficient - an overview | ScienceDirect Topics
Static pressure recovery coefficient is calculated as follows: (8) c p = P 4 ... Loss coefficient of the diffuser is calculated using the following equation:.
[45]
[PDF] Performance Prediction of Straight Two•Dimensional Diffusers
COMPARISON OF IDEAL, CALCULATED, AND MEASURED C. We follow the standard definition of pressure recovery coefficient, Cp. Pe - pi. pC=p- where pe and pl are the ...Missing: formula | Show results with:formula
[46]
Static Pressure Recovery Effects of Conical Diffusers with Swirling ...
Jun 8, 2020 · This link between diffuser geometry, swirl, and performance is investigated using a hybrid RANS-LES based computational model.<|control11|><|separator|>
[47]
The Influence of Inflow Swirl on Cavitating and Mixing Processes in ...
By passing the liquid through the Venturi tubes, the local pressure drops down to the saturation vapor pressure due to a decrease in the throat area, which ...
[48]
[PDF] ISO 5167-4
Mar 1, 2003 · This part of ISO 5167 deals with the three types of classical Venturi tubes: a) cast; b) machined; c) rough welded sheet-iron. A Venturi tube is ...
[49]
Stainless Steel Venturi Tubes for Efficient Flow Measurement - Alibaba
4.3 330 Material Composition. Stainless steel—particularly grades 304 and 316—is the most common material for Venturi tubes due to its excellent corrosion resistance, ...
[50]
Comparative Analysis of Orifice Plates and Nozzles in Differential ...
High permanent pressure loss: ~40–80% of differential pressure is lost. ... Lower permanent pressure loss: only ~10–20% of differential pressure is lost.
[51]
The Venturi Water Meter: An Instrument Making use of a New ...
Jan 1887. The Venturi Water Meter: An Instrument Making use of a New Method of Gauging Water, Applicable to the Cases of Very Large Tubes, and of a Small ...
[52]
[PDF] CFD-driven optimization of a Venturi tube for wastewater treatment ...
Jun 30, 2023 · The CFD model is extended by. 30 and 80 mm before and after the L1 and L5 segments to achieve fully developed turbulent flow and prevent.Missing: modern | Show results with:modern
[53]
Orifice, Nozzle, and Venturi Flow Meters: Principles, Calculations ...
Measurement of fluid flow using small bore precision orifice meters. ASME MFC-14M-2001. International Organization of Standards (ISO 5167-1:2003). Measurement ...
[54]
Types of Orifice Plate used in Flow Measurement
Concentric, Eccentric & Segmental Orifice Plates. There are three types of flow measuring orifice plate that the instrument engineer is likely to encounter, ...
[55]
Types of Orifice Plates and Their Applications - Just Measure it
1. Concentric Orifice Plate · 2. Eccentric Orifice Plate · 3. Quarter-Circle Orifice Plate · 4. Conical Entrance Orifice Plate · 5. Integral Orifice Plate · 6.
[56]
Types of Orifice Plates Used in Flow Measurement - BBP Sales
Concentric Bore – The most common orifice plate is the square-edged, concentric bored design. · Eccentric Bore · Segmental Bore – · Quadrant Edge Bore – · Ring Type ...
[57]
What Are the Different Types of Orifice Plates? - Flowell Corporation
Nov 25, 2024 · An eccentric orifice plate features an offset hole positioned closer to the edge of the plate. This design allows heavier or more viscous fluids ...
[58]
Orifice plates pressure loss – An improved theoretical equation for ...
Mar 31, 2025 · This paper introduces a theoretical equation for predicting the Pressure Loss Ratio (PLR) in incompressible flow, refining existing models proposed by Urner ...
[59]
Effects of Varying Orifice Diameter and Reynolds Number on ...
Aug 5, 2025 · It has been also found that the orifice discharge coefficient reduces with increasing in Reynolds number for all values of beta ratio especially ...
[60]
[PDF] Orifice Plate Meter Diagnostics - ASGMT
The Pressure Loss Ratio (or “PLR”) is the ratio of the PPL to the traditional DP. For a correctly operating orifice meter the PLR is a known value. ISO 5167 [3] ...
[61]
[PDF] Oil and Gas Custody Transfer
Custody transfer, or fiscal metering, is when fluids/gases are exchanged between parties, where payment is based on the amount transferred, requiring high ...
[62]
What Industries Use Orifice Plates? - Flowell Corporation
Nov 26, 2024 · Custody Transfer: Ensuring accurate measurement during the transfer of ownership of oil or gas. Orifice plates are particularly valued in ...
[63]
Mass flow rate measurement of gas-liquid two-phase flow using ...
In this paper, a multi-sensor experimental measurement device is designed based on NIR, acoustic emission sensors, and throated Venturi.
[64]
Two-phase flow measurement through orifice-meter with regression ...
Aug 9, 2025 · Two-phase flow measurement through orifice-meter with regression analysis. January 2024; International Journal of Fluid Mechanics Research 52(2).
[65]
VENTURI METERS - Thermopedia
The discharge coefficient of a Venturi meter is typically 0.985, but ... However, because most of the differential pressure is recovered by means of ...
[66]
Venturi tubes - ISO 5167-4:2003
ISO 5167-4:2003 deals with the three types of classical Venturi tubes: cast, machined and rough welded sheet-iron. A Venturi tube is a device which consists ...
[67]
The Factors that Impact Venturi Meter Accuracy - Primary Flow Signal
Sep 9, 2019 · Accuracy of +/-1.0 to +/-2.0 percent of actual rate of flow down to approximately 125,000 pipe Reynolds number (Rd). Head loss ranging from ...
[68]
Full article: Influence of design parameters of upstream Venturi ...
Feb 28, 2023 · This study uses a computational fluid dynamics approach to evaluate the effect of HBD and VEL on multiphase flow measurement.
[69]
U-Tube Differential Pressure Manometers - The Engineering ToolBox
Inclined and vertical u-tube manometers used to measure differential pressure in flow meters like pitot tubes, orifices and nozzles.
[70]
Inclined tube manometer - Dosch Messapparate GmbH
The inclined tube-pressure gauges D5 and D580 are particularly used for measuring low and extremely low pressures, vacuums, and differential pressures.
[71]
Introduction to Differential Pressure Measurement - WIKA blog
Differential pressure measurements allow users to monitor filter conditions, liquid levels, flow rates, and even the torque of a hydraulic motor.Missing: effect | Show results with:effect
[72]
[PDF] Response of common flowmeters to unsteady flow - DiVA portal
This report gives information on the response of several different types of flow meters to pulsating flows. The flow meters tested are based on pressure ...Missing: SCADA integration
[73]
Connecting a Venturi Flow Meter (or any 4-20mA ... - SCADAmetrics
Dec 5, 2023 · The EtherMeter provides a robust SCADA connection, as it can transmit both totalization and rate-of-flow using modern industrial Ethernet protocols.Missing: factors dynamic response
[74]
SmartLine Wireless Differential Pressure | Honeywell
SmartLine® Wireless Differential Pressure Transmitters are offered in two different series: the high-performance Series 800, and the high-value Series 700.
[75]
https://zeroinstrument.com/effective-temperature-and-pressure-compensation-strategies-for-fluids-liquids-gases-and-steam/
[76]
Effective Temp & Pressure Comp for Fluids: Liquids, Gases, Steam
In this article, we will delve into effective temperature and pressure compensation strategies based on the unique characteristics of liquids, gases, and steam.
[77]
[PDF] Flow Measurement
2. The equation can be written in terms of the ideal gas or the real gas relative density. The Flow Computer Division of Emerson Process Management.<|separator|>
[78]
[PDF] Real Gas Corrections for High Beta Ratio (β > 0.25) Critical Flow ...
Herein, we derive the Real Gas Model from the conservation laws, and provide numerical solutions of the real gas correction factor. In this work the Real Gas.
[79]
Pressure Temperature Compensation Flow Measurement - Inst Tools
Nov 2, 2023 · Pressure Temperature Compensation is applicable when we have DP flow elements like Orifice, venturi, pitot tube, etc for flow measurement.
[80]
Venturi Flow Equation and Calculator - Engineers Edge
A Venturi meter is used to measure the flow rate through a tube or volumetric flow rate, Q ... Qmass = ρ · Q. Where: Q = volumetric flow rate (m3/s, in3/s)
[81]
[PDF] The Discharge Coefficient and Through-Life Performance of Venturi ...
Hydraulically smooth Venturi tubes show a slight increase in discharge coefficient with increasing Reynolds number. The discharge coefficient is sensitive ...
[82]
Gas-Liquid Multiphase Flow Measurement in Venturi Tube Through ...
Gas-Liquid Multiphase Flow Measurement in Venturi Tube Through Data-Driven Modelling. Abstract: Precise quantification of multiphase flow rates holds paramount ...
[83]
Utilizing the Venturi Effect for Natural Ventilation in Buildings
The Venturi effect, using pressure differences, creates forced air flow through narrow passages, like Venturi tubes, to induce natural ventilation in buildings.
[84]
Passive Ventilation: Stack Effect & Bernoulli's Principle - SimScale
Jun 1, 2023 · Learn about different passive ventilation effects, stack ventilation and Bernoulli's principle, and when to use different ventilation types.
[85]
Wind Towers: A Passive Cooling Solution - Architecture Helper
May 23, 2025 · ... Venturi effect, boosting airflow efficiency. For instance, modern wind towers that incorporate wetted surfaces have been found to lower ...
[86]
https://www.growirrigation.com/collections/mazzei-venturi-fertilizer-injectors
[87]
Mazzei Venturi Fertilizer Injectors - Grow Irrigation
Mazzei Venturi Injectors provide a simple, accurate and reliable way to inject fertilizers and other chemicals into your irrigation water.Missing: atomizers firefighting
[88]
Understanding the Venturi Effect in Firefighting - APX Data
Feb 22, 2023 · Venturi scrubbers: These devices use the Venturi effect to mix water and air, creating a fine mist that can be used to control and extinguish ...Missing: atomizers | Show results with:atomizers
[89]
Determination of Standard Oxygen Transfer Rate in Venturi Aeration ...
The oxygen transfer coefficient found to be increased by 31% and 55% at 40 and 80 mm throat length respectively, with increasing the discharge. The rate of DO ...
[90]
Enhanced wind energy harvesting through omnidirectional airflow ...
Dec 4, 2024 · By leveraging the Venturi effect and ordered channels, the design accelerates airflow with a circumferential structure in the central area. This ...
[91]
Overview improving the efficiency of a wind turbine by using a ...
Additionally, augmentation devices that utilize the Venturi effect can be used to enhance wind speed at the inlet, thereby improving energy capture. Solar ...
[92]
What Is a Venturi Tube Used For? - Flowell Corporation
Aug 7, 2024 · The minimal pressure loss characteristic of the Venturi tube ensures that HVAC systems can operate efficiently and effectively, reducing energy ...
[93]
[PDF] Past, Present, Future Erosion at Locke Island
Because of the venturi effect, maximum erosion occurs where the river channel is the narrowest. This could migrate over time, depending on amount and location ...
[94]
Aerodynamics of the Cupped Wings during Peregrine Falcon's ...
Aug 9, 2025 · ... Indeed the constriction (even in an open channel like this) of flowing down the narrow slots will induce a Venturi effect by which there ...
[95]
The Venturi effect and cerebrovascular ultrasound - PubMed
The Venturi effect is a phenomenon of hydrodynamics which describes a drop in hydrostatic pressure along areas of high flow velocities.
[96]
Continuous murmur - the auscultatory expression of a variety ... - NIH
Systolic suppression of the murmur is caused by both mechanical narrowing of the fistulous tract during systole as well as the probable Venturi effect created ...
[97]
ACTIVE BRANCHIAL AND RAM GILL VENTILATION IN FISHES
Opercular aspiration also may be facilitated by the venturi effect as water streaming along the body passes the gill-cover margins in spite of some drag ...
[98]
Oxygen Administration - StatPearls - NCBI Bookshelf - NIH
Jan 22, 2025 · Based on the Bernoulli principle, Venturi masks are another high-flow oxygen delivery option. These air-entrainment masks deliver oxygen at a ...
[99]
[PDF] Analysis of the relationship between flow patterns in the post ...
This plaque buildup creates a venturi effect, resulting in a pressure gradient across the stenosis. Research has shown that this pressure gradient is directly ...