基于本征正交分解的脉冲射流尾迹分析

Subjects: Mechanics >> Oscillation and Wave submitted time 2022-11-01 Cooperative journals: 《应用力学学报》

陈款1 ,张艳华2 ,雷玉昌3 ,卢昂3 ,张登成2

Abstract： The unsteady flow field of an airfoil under the action of pulsed jet is numerically simulated based on the Reynolds average N-S equation.The proper orthogonal decomposition(POD)method is used to analyze the variation of small-scale vortex structure in the wake of low-frequency,medium-frequency,and high-frequency pulsed jet.The results show that with the help of the POD method,the motion state of the wake small-scale vortex structure can be effectively extracted.The low-order modes extracted by the POD method mainly reflect the static separation structure of the wake vortex with the greatest intensity in the wake,corresponding to the main frequency component of the pulsed jet.The higher-order modes mainly reflect the flow state inside or between the wake vortices,corresponding to the high-order frequency doubling components of the pulsed jet.The mutual stretching within the wake vortex contains a wide range of frequencies,and the traction decomposition between the wake vortices contains a single frequency.Only a pair of main wake vortices can be extracted from the wake at low frequency,and many pairs of wake vortices with the same intensity can be extracted from the wake at high frequency.At low frequency,the wake vortex is single and the interaction is simple.The first six modes can be used to characterize the flow field structure.At high frequency,the number of wake vortices is large and the interaction is complex,so higher order modes are needed to characterize the flow field structure.

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