Analysis of Flow Fluctuation of Confined Backward-Facing Step Based on Pulsation Tracking Network Method

Abstract

Abstract Backward-facing step is a common flow model in hydraulic machinery. Its main feature is that there is a sudden expansion structure at the downstream of the flow channel, which causes the flow instability and is easy to form a vortex behind the sudden expansion section. At present, there are many studies on backstage step flow, but the dominant frequency fluctuation of its flow information has not been noticed. Based on the pulsation tracking network (PTN) method, the numerical simulation of a typical backstage step flow is carried out in this paper. The numerical simulation results are in good agreement with the experimental results. The results of numerical simulation are analyzed in frequency domain by using FFT to obtain the main frequency distribution of flow information on the typical section of the backstage step flow and the distribution of pulsation amplitude at each frequency. It explores a new direction for future research.