Strategies for Tractable Turbulent Inflows in High-Fidelity Simulations

Imposing realistic turbulence is a challenging and expensive aspect of high-fidelity simulations. Modern turbulent-inflow methods still require substantial streamwise distances for profiles to fully develop. This computational burden leads to cost-versus-accuracy compromises. The inner-layer relaxes faster than the outer-layer in turbulent boundary layers, leading to many applications foregoing complete outer-layer relaxation. Additionally, commonly used methods require a priori statistics that are seldom available at targeted conditions. These challenges are addressed by the proposed work. Several cost-saving strategies are explored: sponge zones for faster development, wall-modeled inflow regions to alleviate grid requirements, and inflow pressure treatments to damp artificial acoustic contamination. Next, strategies for generating inflow turbulent statistics are explored. The proposed work explores the differences in relaxation distance when using lower-fidelity methods to generate inflow stresses compared to scaling high-fidelity databases to different conditions. This will aid future practitioners in determining the best way to generate inflows when databases are not available at desired Mach or Reynolds numbers.