Flow through a Venturi pipe

The following examples concern flows through Venturi pipes, as often encountered in boats for instance. In "real life", this Venturi pipe represents a small device used to drain sailing boats. If the flow speed is sufficiently high, then - due to the Bernoulli principle - the narrowing section gives rise to a low pressure which creates a flux through this small device, out of the boat. Therefore, we are mainly interested in controlling both the instantaneous and the mean flux through this device. See the following figure for a sketch of the geometry and the location in a boat, as well as a snapshot from a corresponding numerical simulation.

Right behind the narrowing section - below the small device - the flow separates and produces complex flow patterns, oscillating in space and time. As explained before, the corresponding flux through the small device and the body forces acting on the walls of the pipe are of major interest, and a difficult numerical job to do! The complexity of the problem depends on the:

• inflow speed
• viscosity
• size and width of the pipe, w.r.t. the shape of the small upper device

A systematic variation of these different configurations is part of the following flow situations.

• Flow through a Venturi pipe at low up to medium Reynolds number
• Flow through a Venturi pipe at medium up to high Reynolds number