Simulation of Low Reynolds Number Isotropic Turbulence Including the Passive Scalar

Full simulations of homogeneous isotropic turbulence containing a homogeneous passive scalar were made at low Reynolds numbers and various Prandtl numbers. The results show that the spectral behavior of the two fields are quite similar; both fields decay as power-law functions of time. However. the decay exponent is quite dependent on both the Reynolds and Prandtl numbers. The decay exponent of the velocity field seems to felt off somewhat faster as a function of Reynolds number than experiments indicate. The behavior of the velocity derivative skew ness is in good agreement with the experimental results but indicates a different trend with Reynolds number than the experiments.