Author(s): Thomas Gerz
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Keywords: No Keywords
Abstract: Direct numerical simulations have been performed to study the influence of anisotropic initial conditions on the development of neutrally or stably stratified homogeneous turbu-lent shear flows. Further, the influence of zero initial available potential energy E_ (pot) on the development of a counter-gradient vertical heat-flux in a stably stratified shear flow is considered. Both studies are compared with corresponding results obtained by Gerz, Schumann & Elghobashi (1989) where the turbulent fields have been isotropically initial-ized and where E_ (pot) had a non-zero initial value. Finally, simulations with different resol-utions of the numerical grid using 96~3 or 128~3 grid points have been carried out in addition to previous 64~3-cases performed by Gerz et al. (1989) in order to study the role of proper resolution of the temperature-variance spectrum at high wave numbers for the occurrence of counter-gradient heat-fluxes in a high Prandtl-number flow (Pr=5).
Year: 1989