Influence of the hydrofoil trailing-edge shape on the temporal-spatial features of vortex shedding

Abstract

Ocean energy is a kind of clean and valuable renewable resource, which can be efficient utilized through turbomachinery. The turbulent pulsation effect and unsteady flow regime will cause pressure pulsation which can destroy the stability of the unit, especially at the tailing edge of blade. This paper compares pressure field change in the downstream region with different trailing edge geometry by numerical simulation and the pulsation tracking network method. The reasons for weakening downstream pressure pulsation with the Donaldson modification and the propagation law of the pressure pulsation are clarified. By Donaldson modification, the main frequency of pressure pulsation becomes the frequency of vortex shedding (fvs) and the amplitude is reduced to 10% of the original value. The propagation law of pressure pulsation has changed and the scope of influence has been expanded. The position of vortex generation can be judged by the phase variation. The weakening of the fvs amplitude is due to the stable low-pressure region and the phase difference variation. The inhibition of the convergence effect of vortex causes the weakening of the 2fvs amplitude. This study provides an effective method and reference for understanding the downstream pressure pulsation variation of shedding vortex.