Venturi Tube
Fluid flows through a tube that narrows and widens. As the cross-section decreases, velocity increases and pressure drops — Bernoulli's principle made visible through particle flow, pressure gauges, and a manometer.
About this lab
The Venturi effect is a direct consequence of Bernoulli's principle, which states that for an inviscid, incompressible fluid in steady flow, the sum of pressure energy, kinetic energy, and potential energy per unit volume remains constant along a streamline. When fluid enters a constricted section of pipe, conservation of mass (the continuity equation, A₁v₁ = A₂v₂) demands that the velocity increase. Bernoulli's equation then requires the static pressure to decrease correspondingly: P + ½ρv² = constant. The manometer tubes rising from the pipe make this pressure difference directly visible — the fluid column is lower where velocity is highest.
Giovanni Battista Venturi first described this phenomenon in 1797, though the underlying principles were established by Daniel Bernoulli in his 1738 work Hydrodynamica. The Venturi tube became one of the most important devices in fluid mechanics. In engineering, Venturi meters are used to measure flow rates by relating the pressure drop across the constriction to flow velocity. The same principle operates in carburetors, where air accelerating through a venturi draws fuel into the airstream, and in aspirators, where a high-velocity water jet creates suction.
This simulation models ideal incompressible flow through an axially symmetric tube. Particles are advected according to the local velocity field derived from the continuity equation, and colored by speed to visualize the velocity gradient. The pressure at each section is computed from Bernoulli's equation relative to the wide-section reference pressure. Real flows would also exhibit viscous boundary layers and potentially turbulence at high Reynolds numbers, effects not captured in this ideal-fluid model.