RESEARCH ON THE IMPACT OF SHOCK WAVE TO EXTENSIONALITY OF POD METHOD

摘要

In this paper, flow reconstruction accuracy andflow prediction capability of discontinuoustransonic flow field by means of properorthogonal decomposition (POD) method isstudied. The ability to reconstruct and predictflow flied is called extensionality of PODmethod in this paper. Although, only using a fewmodes, we can capture the information ofsubsonic flow field. When it counters the shockwave, the smoothness of the solution near theshock wave cannot be guaranteed. The modalcoefficients are interpolated or extrapolated anddifferent modal components are superposed torealize the prediction of the flow field beyondthe snapshot sets. Results show that comparedwith the subsonic flow, the transonic flow withshock wave requires more POD modes to reacha comparative reconstruction accuracy. When ashock wave exists, the interpolation predictionability is acceptable. However, large errorsexist in extrapolation, and increasing thenumber of POD modes cannot effectivelyimprove the prediction accuracy of the flowfield.