The Cavermod device: Hydrodynamic aspects and erosion tests

The Cavermod (CAVitation ERosion MODel) is an erosion rest device first des cribed by Dominguez-Cortazar et al. (1992, 1997). Recently, it was modified in two steps: first by increasing its maximum rotation rate (from 4500 to 8000 rpm) and second by shortening its vapor core (from 156 to 66 mm). This paper plans to present the main results which are obtained in both configu rations (long and short vortex) and for "slow" or "rapid" regime of rotatio n. They mainly concern 1. the hydrodynamic aspects of the vapor core collap se, as deduced from observation of rapid films (evolution of the vortex len gth, collapse velocity), 2. the erosion patterns produced on metallic targe ts such as pure aluminium and copper. A second companion paper will present the results of force measurements in both configuration and an attempt to estimate the local erosive pressures.