Cavitation Flows Past a Rotating Circular Cylinder

Abstract

Cavitating flows around a rotating circular cylinder at the low Reynolds number flow (Re = 400) are numerically investigated. The computation is performed by incorporating a compressible homogeneous liquid-vapor two-phase flow and a homogeneous equilibrium mass transfer model. The simulation is well-validated for the cavitating and non-cavitating flows over various objects in literature. The computation is then carried out for the rotating cylinder to analyze the combined effects of cavitation and self-rotation on the resultant load. The results state a high influence of the rotation speed ratios γ (a ratio of the cylinder's rotation velocity to the flow velocity) on the flow regime. For non-cavitation, the Karman vortex street is observed for γ < 2.0 while a nearly steady state results in a higher value. Under the Magnus effect, a larger lift is produced but also obviously increases the friction drag on the cylinder. Regarding the cavitation condition, the computation demonstrates an obvious reduction in the friction drag, leading to a decrease of the total drag of a rotating cylinder by about 52% compared to that without cavitation, while retaining reasonable lift. Almost constant load on the cylinder is found at low γ > 1.5 and cavitation number σ̍p0−pv12ρU02≤ 1.0, which is significant for designing and extending the working durability of an underwater moving object.