In this chapter, direct numerical simulations (DNSs) of compressible turbulent
flows for thermally perfect gas (TPG) and calorically perfect gas (CPG), including two
wall temperature of 298.15K (low temperature condition) and 596.30K (high temperature
condition), are performed to investigate the influence of a gas model on the turbulent
statistics and flow structures. The results show that the influence of TPG is negligible and
remarkable for low and high-temperature conditions, respectively. Many of the statistical
characteristics used to express low-temperature conditions for CPG still can be applied
to high-temperature conditions for TPG. The smaller the influence of the gas model on
the mean and fluctuating velocity, the stronger the Reynolds analogy. The static
temperature for TPG is smaller than that for CPG, whereas an inverse trend is found for
turbulent and root square mean Mach numbers. Omega could capture both strong and
weak vortices simultaneously for compressible flow, even TPG, which is difficult from
Q. Compared to the results of CPG, the vortex structure becomes smaller, sharper and
more chaotic considering TPG.
Keywords: Calorically perfect gas, Compressible flow, Direct numerical simulation,
Thermally perfect gas, Vortex structure.