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 noncavitating 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 ratio γ (a ratio of the cylinder's rotation velocity to the flow velocity) on the flow regime. For noncavitation, 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 σ = p0−pv12ρU02≤ 1.0, which is significant for designing and extending the working durability of an underwater moving object.