Financial support : FUI Plateforme
In a liquid, cavitation is the appearance of vapor bubbles caused by the fluid passing below vapor pressure, most often due to high pressure variations around obstacles.
Cavitation erosion is the material removal from the solid boundaries due to the collapse of vapour bubbles in a liquid flow. It is one of the major reasons for the failure of technical devices involving the processing of liquids at large pressure differences (pumps, injectors, turbines, ...).
With the aim of better understanding and possibly alleviate cavitation damage, we study numerically the dynamics of cavitating flows around obstacles (as turbine blades). Our numerical approach employs a simplified homogeneous mixture or ‘single fluid’ model in a solver for compressible flows based on the finite volume method. This code has been previously developed, tested and exploited at the single-bubble scale (PhD of P. Sarkar), and we want now to extend it to a macroscopic scale.
The time evolution of this compressible solver is based on a semi-implicit time integration, with a time splitting that allows the code to be stable even if the acoustic waves are not time-resolved. The main advantage is to be able to run rapid compressible simulations whenever pressure waves are not important for the flow development.
One limitation in this efficient time advancement is nevertheless the use of non-reflective, but explicit in time, inlet and outlet boundary conditions, that obliges to resolve the pressure waves at the concerned boundaries and severely limits the time step.
By studying the academic situation of a flow around a cylinder, we have successfully improved the stability of the code. Cavitation development around the cylinder is currently under study.
