Modeling the impact pressure of a free falling liquid block with OpenFOAM

• The free fall of a rectangular block of a compressible liquid, surrounded by a gas, impacting on a flat floor is considered.
• The impact pressure peak is the main result.
• This case and method can become a new simulational frame for violent liquid impacts.
• Simulations are carried out with the finite volume open-source package OpenFOAM.

A canonical wave impact problem is considered: the free fall of a rectangular block of a liquid, surrounded by a gas, which impacts on a flat floor. This problem calls for an explicit treatment of compressibility, which is directly responsible for the pressure and density sonic waves caused by the impact. The problem was first considered by Braeunig et al. at ISOPE, 2009, where they explored a wide range of liquid/gas density ratios, and other physical parameters. However, a proper mesh convergence analysis was lacking, therefore the numerical results provided there could only be used to identify trends. We take here a different route, by carefully analyzing some selected cases but discussing mesh convergence in detail. Our aim is to provide for the community a firm simulational frame for this sort of problems. Computations have been carried out with the finite volume open-source package OpenFOAM, within a volume-of-fluid approach and a transient solver. We have developed a code extension in order to implement the Cole (“stiffened”) equation of state.