ABSTRACT

This study focuses on the prediction of the hydrodynamic and hydroacoustic performance of a cavitating marine propeller in open water condition using Reynolds-averaged Navier-Stokes (RANS) and Detached Eddy Simulation (DES) solvers. The effectiveness of the methods is investigated for the recently introduced benchmark propeller that belongs to the research vessel ‘The Princess Royal’. The main emphasis of the study is to examine the capabilities of the RANS and DES solvers for predicting the hydrodynamic performance of a propeller in the presence of sheet and tip vortex cavitation (TVC). In the numerical simulations of the cavitating propeller flow, the Schnerr-Sauer cavitation model based on a reduced Rayleigh-Plesset equation was used to model the sheet and tip vortex cavitation. An alternative Vorticity-based Adaptive Mesh Refinement (V-AMR) technique was employed for the accurate realisation of the TVC in the propeller’s slipstream. In the hydroacoustic calculations, a porous Ffowcs Williams Hawkings equation (P-FWH) was employed together with the DES solver. The numerical hydrodynamic and hydroacoustic results are compared with those of experimental data for the benchmark propeller available from the University of Genova Cavitation Tunnel. The results show that both the RANS and DES solvers are successful for modelling of the sheet cavitation on the propeller blades. However, the prediction of the TVC extension using the RANS solver is found to be insufficient in comparison to the TVC prediction when using the DES method. This is due to the inherent modelling limitations of the RANS solver. In addition to hydrodynamic performance predictions, the overall noise spectrums were found in an agreement with the experimental data with discrepancies between the low and high-frequency region.

摘要

本研究的重点是使用雷诺平均纳维-斯托克斯 (RANS) 和分离涡流模拟 (DES) 求解器预测空化船用螺旋桨在开阔水域条件下的水动力和水声性能。对最近推出的属于研究船“皇家公主号”的基准螺旋桨的方法的有效性进行了调查。该研究的主要重点是检查 RANS 和 DES 求解器在存在薄片和叶尖涡流空化 (TVC) 时预测螺旋桨流体动力学性能的能力。在空化螺旋桨流的数值模拟中，基于简化的 Rayleigh-Plesset 方程的 Schnerr-Sauer 空化模型用于模拟片状和叶尖涡流空化。另一种基于涡度的自适应网格细化 (V-AMR) 技术用于准确实现螺旋桨滑流中的 TVC。在水声计算中，多孔 Ffowcs Williams Hawkings 方程 (P-FWH) 与 DES 求解器一起使用。数值流体动力学和水声结果与热那亚大学空化隧道提供的基准螺旋桨的实验数据进行了比较。结果表明 RANS 和 DES 求解器都成功地模拟了螺旋桨叶片上的片状空化现象。然而，与使用 DES 方法时的 TVC 预测相比，使用 RANS 求解器对 TVC 扩展的预测是不够的。这是由于 RANS 求解器固有的建模限制。