Experimental Study on the Influence Characteristics of Yaw Angle and Rudder Angle on Propeller Cavitation Inception and Pressure fluctuations

In this paper, we employed a multi-field synchronous measurement system to conduct a systematic experimental study on a submarine-propeller integrated model in the China Large Cavitation Channel, comprehensively investigated the influence patterns of changes in typical maneuvering parameters (yaw angle and rudder angle) on propeller hydrodynamic performance and cavitation inception, and analyzed the influence characteristics of different types of cavitation morphology and their unsteady evolution processes on pressure fluctuations. The experimental results showed that under steering and yaw conditions, on the one hand, the thrust coefficient and torque coefficient significantly decreased; on the other hand, the inception of tip vortex cavitation (TVC) and sheet cavitation occurred significantly earlier, severely limiting the safe operating area of propellers. The characteristics of tip vortex cavitation inception under different criteria were investigated. Specifically, under optical criteria, tip vortex cavitation inception points appeared later than tip vortex cavitation disappearance points, while tip vortex cavitation inception occurred earlier under acoustic criteria than under optical criteria. After cavitation occurred, distinct high-order shaft frequency and blade passing frequency components appeared in pressure fluctuation, and all these components increased significantly from low-order to high-order harmonics. Under the influence of the high wake behind the rudder tail, tip vortex cavitation underwent cavitation inception followed by rapid growth, while under the influence of low wake, tip vortex cavitation underwent cavitation collapse until cavitation disappeared. The unsteady evolution of tip vortex cavitation led to periodic drastic variations in stern pressure fluctuation.