Numerical analysis of three-dimensional sound propagation in soft-soft or soft-hard circular ducts with circumferential and axial modes of sound sources at the inlet has been carried out. In this paper , the numerical...Numerical analysis of three-dimensional sound propagation in soft-soft or soft-hard circular ducts with circumferential and axial modes of sound sources at the inlet has been carried out. In this paper , the numerical method and the samples are offered and the effects of circumferential and axial modes on numerical results are discussed in detail .展开更多
The full annulus numerical research was performed on a low-speed compressor rotor to investigate the rotating instability in the tip region.The frequency spectra show the existence of rotating instability at narrow st...The full annulus numerical research was performed on a low-speed compressor rotor to investigate the rotating instability in the tip region.The frequency spectra show the existence of rotating instability at narrow stable operating range.With the decrease of flow rate,31 cells of flow disturbance can be found in the instantaneous flow field.The distribution of vortex suggests that the circumferential propagation of the interaction between tip leakage vortex and adjacent blade brings about these cells.The dynamic mode decomposition(DMD)method and spatial discrete Fourier transform(SDFT)were applied to obtain the circumferential mode features,and the results indicate that the rotating instability is associated with the 31 cells of flow disturbance.Then the DMD method was further applied on the pressure data from a circle and an annulus domain,so as to extract different mode components with the corresponding spatial structures,frequencies and amplitudes.The results suggest that DMD modes can display the flow feature and explore the evolution of each instability source in the tip flow field.展开更多
基金The project is supported by National Natural Science Foundation of China and National Education Commission Foundaion of China
文摘Numerical analysis of three-dimensional sound propagation in soft-soft or soft-hard circular ducts with circumferential and axial modes of sound sources at the inlet has been carried out. In this paper , the numerical method and the samples are offered and the effects of circumferential and axial modes on numerical results are discussed in detail .
基金This work was supported by Natural Science Foundation of Shanghai(Grant No.18ZR1418600)National Natural Science Foundation of China(Grant No.11202132).
文摘The full annulus numerical research was performed on a low-speed compressor rotor to investigate the rotating instability in the tip region.The frequency spectra show the existence of rotating instability at narrow stable operating range.With the decrease of flow rate,31 cells of flow disturbance can be found in the instantaneous flow field.The distribution of vortex suggests that the circumferential propagation of the interaction between tip leakage vortex and adjacent blade brings about these cells.The dynamic mode decomposition(DMD)method and spatial discrete Fourier transform(SDFT)were applied to obtain the circumferential mode features,and the results indicate that the rotating instability is associated with the 31 cells of flow disturbance.Then the DMD method was further applied on the pressure data from a circle and an annulus domain,so as to extract different mode components with the corresponding spatial structures,frequencies and amplitudes.The results suggest that DMD modes can display the flow feature and explore the evolution of each instability source in the tip flow field.
