Georg Hammerl

Cavitation is a multi-phase problem that includes the growth and collapse of vapor bubbles in liquid induced by a locally varying pressure. Cavitation nuclei which are the starting point for a vapor bubble are ubiquitious in any liquid. Their number can be excessive (up to O(10⁸/m³) but with current computer resources it is possible to track each of these nuclei. The approach chosen consists of an Euler-Lagrange framework in which the liquid is treated as continuous phase and the bubbles are modeled as dispersed phase which is tracked in the Lagrangian framework. The interaction between the the phases includes the forces from the liquid on the bubbles as well as vice versa. Furthermore, the volume occupied by the bubbles is accounted for as void fraction in the liquid. In order to complete the four-way coupling the collision of bubbles is also taken into account. This meso-scale approach lying between a fully resolved multi-phase approach with a sharp interface and a simplified Euler-Euler approach allows to track each bubble with its position and size. This information can be used to determine possible damage of a submerged structure due to the collapsing vapor bubbles.


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