Suppressing impact intensity of cavitation collapse by micro-protrusions on the cylinder surface

Under specific cavitating flow conditions, the collapse of cavitation structures near the bluff body surface can trigger intense pressure pulsations, resulting in severe vibration and noise. To effectively control the damage caused by the collapse of cavitation structures, this study investigates the cavitation flow field around a cylinder using a compressible numerical simulation method based on implicit large eddy simulation. This work is the first to examine the cavitation control effects of placing micro-protrusions on the surface of a cylinder. The results show that the wall-attached cavitation collapse near the separation point on the cylinder surface is the main cause of induced vibrations and noise. The height and location of the micro-protrusions are key factors in controlling the wall-attached cavitation in the cylinder's shear layer. It is recommended to position the protrusions approximately 5° upstream of the separation point, with the protrusion height entering at least the logarithmic region of the boundary layer. Appropriately placed micro-protrusions can block the reverse flow, reducing the cavitation volume involved in the collapse and the overall collapse intensity, thereby diminishing the load impact on the cylinder surface.