Pulsation temporal-spatial characteristics of vortex-shedding flow under different hydrofoil trailing edge shapes

Hydrofoil trailing edge shape directly influences its downstream flow state. Due to the non-streamlined shape, alternating vortices will form downstream, resulting in complex pressure pulsations. Different shapes of the trailing edge lead to varying pressure pulsations downstream. In this paper, four different trailing edge shapes were selected for numerical simulation based on the National Advisory Committee for Aeronautics 0009 hydrofoil. The main difference lies in trimming one side of the trailing edge to different degrees, making it asymmetrical. Large Eddy Simulation was used and the results were accurate. The optimized multivariate variational mode decomposition was used to extract and reconstruct effective components of pressure pulsation in the flow, and satisfactory reconstruction results were obtained. This combined method effectively identifies key components influencing flow field and enables reasonable reconstruction. Results show that shedding vortices on both sides of an asymmetric hydrofoil's tailing edge exhibit noticeable differences in morphology. Pressure pulsation distribution in the trailing-edge flow field was primarily influenced by components near vortex-shedding frequency. With the deepening of the asymmetric trimming degree, the pressure pulsation influenced by this component on that side is gradually weakened, but the energy peak of pressure pulsation in the flow field is less reduced.