705 / 2019-04-30 23:00:17

DMD as a tool for Investigation of the dynamic characteristics of the supersonic wake

Supersonic, Dynamic mode decomposition, Wake instability, Spectrum

全体主题 > 数值模拟、建模与CFD

A numerical research is carried out to investigate the dynamics of a wedge in the supersonic flow. LES is employed to acquire the flow field parameters in a period of time. Then DMD is employed to analyze the LES data. The wake flow in the supersonic free stream is analyzed by DMD method. A single peak can be found in the DMD spectrum, corresponding to the st number equals 0.4. The X component of the mode corresponding to this frequency shows an asymmetric pattern, while the Y component is of symmetric pattern. A dominant frequency corresponding to st=0.2 appears in the recirculation area behind the wedge, but quickly dies out along the flow direction up to the area between 15d to 20d. The second harmonic of that frequency become dominant downstream, giving evidence of the global dynamic characteristics being a consequence of the near-wake instabilities.