Mulitpoint Correlations in Direct Numerical Simulations

We examine the Markov properties of the three components of a turbulent flow generated by a DNS simulation of the flow around an air-foil section. The spectral element code Nektar has been used to generate a highly resolved flow field around an fx79w-151a airfoil profile at a Reynolds number of Re=5000 and an angle of attack of alpha = 12 degrees. Due to a homogeneous geometry in the spanwise direction, a Fourier expansion has been used for the third dimension of the simulation. In the wake of the profile the flow field shows a von Karman street like behavior with the vortices decaying in the wake. Beneath a turbulent field appears. Time series of the 3D flow field were extracted from the flow field to analyse Markov properties of the flow field in different areas in the surrounding of the airfoil. The aim is to evaluate if the n-point correlations and Reynolds stresses can be approximated by a stochastic process governed by a Fokker-Planck equation, which could be the basis of a stochastic closure of the Reynolds equations. Here the method and first results are being shown.