Results and Analysis of Implicit Large Eddy Simulations of Equilibrium Spatially Developing Turbulent Boundary Layers at Multiple Mach Numbers

Equilibrium turbulent flat plate boundary layers with time invariant statistics were obtained at Mach numbers 1.7, 2.3, and 2.9. These are to be used as the initial condition for Large Eddy Simulations (LES) or Direct Numerical Simulations (DNS) of shock wave/turbulent boundary layer interactions utilizing a body force-based method. The results obtained are supplemented by an analysis of the mean and statistical properties of the respective boundary layers. The spanwise extent of the domain required to allow adequate decorrelation between the centerline and the boundaries is investigated by extensively probing the flowfields obtained. This is done to quantify the coherent structures of the turbulent flow. Specifically, two point correlations and integral length scales are used to investigate spanwise decorrelation distances in an attempt to pick a computational domain which is large enough to permit decorrelation downstream but small enough to minimize computational costs. It is shown that by examining the precursor events in the upstream region, namely the generalized stability criterion, it is possible to provide estimates for the force field parameters necessary for transition for a given flow, with only a small portion of the domain in the neighborhood of the trip. The technique is made even more efficient by investigating the possibility of determining these parameters using a two-dimensional simulation. Additionally, the three flow fields obtained are surveyed to confirm that they are suitable for subsequent SBLI simulations. We check that (i)they possess the expected turbulent characteristics and (ii)there is no signature of the tripping mechanism.