  Cavitation is a limiting phenomenon in many domains of fluid mechanics.
Instabilities of a partial cavity developed on an hydrofoil, a
converging-diverging step or in an inter-blade channel in turbomachinery, have
already been investigated and described in many previous works. The aim of this
study is to evaluate a passive control method of the sheet cavity. According to
operating conditions, cavitation can be described by two different regimes: an
unstable regime with a cloud cavitation shedding and a stable regime with only
a pulsating sheet cavity. Avoiding cloud cavitation can limit structure damages
since a pulsating sheet cavity is less agressive. The surface condition of a
converging-diverging step, like a Venturi-type obstacle, is here studied as a
solution for a passive control of the cavitation. This study discusses the
effect of an organized roughness, in the shape of longitudinal grooves, on the
developed sheet cavity. Analyzes conducted with Laser Doppler Velocimetry,
visualisations and pressure measurements show that the grooves geometry, and
especially the groove depth, acts on the sheet cavity dynamics. Results show
that modifying the surface condition, by varying the grooves geometry, can
reduce cavity sheet length and even suppress the cloud cavitation shedding.
