Fluid-structure interaction with leaks

Topological changes of the grid in a flow simulation based on mesh-based finite volumes are a major challenge. One of the classic applications in engineering practice is the opening and closing of valves, such as flutter valves or inlet/exhaust valves in piston engines.

The state change of a valve from still currently open to the fully closed state is a singularity. Not only a topology change in the mesh is a result, but also the sudden stop of the flow rate through the valve.

With the meshless method SPH these restrictions are eliminated, as the shown example illustrates.

A liquid is pressed into a tubular impermeable membrane made from hyper-elastic material. At the lower end of the tube a rigid lid is fixed in space. The tube is in this case not firmly attached to the lid.

Copyright: Fraunhofer IWM

While the tube gets filled, it initially increases its radius. The constant volume of the rubbery material having a transverse-contraction-number of nearly 0.5, cause a shortening of the hose. As a result, at the lower end a gap opens and the fluid may eventually flow out.

This is a co-simulation between SimPARTIX® and Abaqus/Explicit.