Generation of inflow turbulent boundary layer for LES computation

When predicting unsteady flow and pressure fields around a structure in a turbulent boundaryrnlayer by Large Eddy Simulation (LES), velocity fluctuations of turbulence (inflow turbulence), whichrnreproduce statistical characteristics of the turbulent boundary layer, must be given at the inflow boundary.rnHowever, research has just started on development of a method for generating inflow turbulence thatrnsatisfies the prescribed turbulence statistics, and many issues still remain to be resolved. In our previousrnstudy, we proposed a method for generating inflow turbulence and confirmed its applicability by LES ofrnan isotropic turbulence. In this study, the generation method was applied to a turbulent boundary layerrndeveloped over a flat plate, and the reproducibility of turbulence statistics predicted by LES computationrnwas examined. Statistical characteristics of a turbulent boundary layer developed over a flat plate wererninvestigated by a wind tunnel test for modeling the cross-spectral density matrix for use as targets ofrninflow turbulence generation for LES computation. Furthermore, we investigated how the degree ofrncorrespondence of the cross-spectral density matrix of the generated inflow turbulence with the targetrncross-spectral density matrix estimated by the wind tunnel test influenced the LES results for the turbulentrnboundary layer. The results of this study confirmed that the reproduction of cross-spectra of the normalrncomponents of the inflow turbulence generation is very important in reproducing power spectra, spatialrncorrelation and turbulence statistics of wind velocity in LES.