Fortran Codes for Computing the Space-Time Correlations of Turbulent Flow in a Channel

摘要

Several groups have recently performed direct numerical simulations of turbulent flow in a channel at low Reynolds numbers. These simulations generate enormous quantities of data which have been used to investigate the validity of current theories of turbulence, etc. However, before detailed investigations can be undertaken, it is important to first check some basic statistics of the turbulence such as the mean velocity profile, turbulence intensities, and Reynolds stress profiles, beyond these one-point statistics so that length and time scales of the turbulence can be determined. This report describes FORTRAN codes which enable rapid evaluation of the two point correlations from a given dataset. Computer codes have been developed which compute the space time correlations in turbulent channel flow. The two-point spatial correlation function is computed by Fourier transforming the appropriate wavenumber spectrum. The wavenumber spectrum is computed by averaging over an appropriate number of ensembles and using geometric symmetries to improve the smoothness of the results. Space-time correlations are computed in a similar manner. Keywords: Symmetries; Correlations. (EDC)