Tip vortex cavitation is typically the first type of cavitation in real ship propellers due to the scale effect. To lessen or eliminate propeller cavitation noise, it is necessary to effectively identify and predict the tip vortex cavitation initiation of the propeller and run the propeller as far as possible in the “non-cavitation area.” However, for the current numerical computation, it is impossible to determine the minimum pressure at the vortex core directly and correctly, making it difficult to anticipate the cavitation initiation of the propeller tip vortex. In this paper, based on computational fluid dynamics (CFD) numerical calculations and the tip vortex model proposed by Xin [Proceedings of 2013 Ship Hydrodynamics Conference (2013), pp. 211–218], we propose a new prediction method for propeller tip vortex cavitation initiation—“the tip vortex model method.” The propeller tip vortex is solved by CFD calculation in this model, and the minimum pressure at the downstream vortex core is examined based on the tip vortex model to determine the initiation of propeller cavitation. We examine the cavitation inception using the tip vortex model method and compare it to the results obtained using the minimum pressure coefficient method and the minimum vapor volume method. It is discovered that the cavitation inception number obtained by the tip vortex model method is closer to the experimental results. Furthermore, the effects of different turbulence models and grid settings on the prediction of tip vortex cavitation initiation are investigated, providing an effective reference for the prediction of propeller tip vortex cavitation initiation.

Due to the scale effect, tip vortex cavitation (TVC) is the earliest type of cavitation that occurs on real ship propellers. As a result, experts in the ship field have been paying close attention to the accurate prediction of propeller TVC inception for a long time. The motion and growth of the microscopic nuclei in the water have a significant influence on TVC inception. However, the minimum pressure coefficient method—a common method at present—based on the traditional Eulerian framework, neglects the influence of microscopic nuclei and therefore cannot accurately predict the cavitation inception. Moreover, the numerical prediction method for cavitation inception, which is based on bubble dynamics models and considers the influence of nuclei, has not established a set of unified and specific discrimination criteria applicable to propeller cavitation inception. In order to make up for the shortcomings of traditional prediction models and the existing methods based on bubble dynamics in the prediction of TVC inception, we propose a new discrimination method for propeller TVC inception based on bubble dynamics in this paper. The comparison with experimental results demonstrates that our proposed method allows us to predict propeller TVC inception more accurately. In addition, the effect mechanism of tip vortex flow characteristics on nuclei evolution is further investigated, and it is found that when approaching the low-pressure region at a vortex core under the influence of tip vortex suction, nuclei grow explosively under the continuous action of the low pressure at the vortex core until they reach their maximum sizes and then collapse rapidly.

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.