Boundary layer development downstream of a cavitation cavity closure.

The results of an experimental investigation of the turbulent boundary layer that develops on a symmetric hydrofoil at moderate Reynolds number when a stable partial cavity takes place in the vicinity of the leading edge at angle of attack of 10 degrees, are presented. The modifications of the mean and turbulent properties introduced by the e existence of the vapour phase have been compared to the same quantities in the non cavitating state. A particular focus has been put on the evolution of the logarithmic law of the velocity profile and on the modification of the global parameters The higher order moments have been studied to highlight the exchanges and transfers of turbulent quantities between the different regions of the boundary layer The results have shown that the vapour phase modify the thickness of this zone of velocity defects and enhance the exchanges with the external layer leading to an increase of the velocity close to the wall. This particular phenomenon is related with a stabilisation of the boundary layer and delays its separation.