Compressible Flows  

Fluctuating Mach number from DNS of turbulent boundary layers at
Re82 around 1370


We have developed a systematic procedure for initializing turbulent wall-bounded flows at controlled Mach number and Reynolds number conditions while minimizing simulation transients. Our developed procedure leads to cost effective direct numerical simulations and allows for controlled flow conditions, which is necessary for one-to-one comparisons against experimental data. As part of this work, we have demonstrated that the data from our direct numerical simulations of turbulent boundary layers exhibit realistic turbulence structure features and dynamics, comparable to those that are found in experiments of incompressible, compressible and atmospheric boundary layers, including the hierarchy of streaks, hairpin vortices, hairpin packets, and superstructures. Our analysis has shown that superstructures carry nearly one third of the turbulent kinetic energy, and that these structures prevail and meander for very long streamwise distances, while beginning and ending in the computational domain. In addition, we have validated the statistical content of the flow against experiments at the same conditions.

We are currently investigating and characterizing the effect of Mach number and heat transfer in supersonic and hypersonic turbulent boundary layers, as well as other high-temperature phenomena that become relevant at hypersonic flow conditions.



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