Cavitation

Abstract

The main goal of this master thesis is to reproduce by CFD computations the characteristic cavitation dynamics in a venturi which were experimentally discovered at TU Delft by Jahangir and al. The different cavitation regimes were obtained by modifying the global static pressure and flow velocity in the flow loop. Based on this, three different cloud cavitation shedding regimes were identified. One of the mechanisms appears at high cavitation number and can be attributed to the presence of a re-entrant liquid jet. Another dominant shedding mechanism was found at lower cavitation number, with the presence of propagating bubbly shock waves. A transition regime was also observed where both mechanisms seem to coexist. A two phases flow model is implemented in the open-source software OpenFOAM. The transition regime from the bubbly shock to the re-entrant jet dominated regime will be identified and compared to experimental findings. The three cavitation shedding regimes will be investigated by using different cavitation numbers. The simulations will mostly be conducted using an inviscid and incompressible solver.