GALCIT Colloquium

NOTE: This seminar will be held virtually. The Zoom link can be found here.

The development of predictive computational fluid dynamics (CFD) tools is critical for the design of next-generation high-speed vehicles for routine and affordable rapid global transport and space exploration. So far, we have only limited understanding of the intricate interaction between turbulence and many important flow processes typical of high-speed flows, such as laminar-turbulent transition, shock wave-turbulence interaction, and thermochemical non-equilibrium. The lack of physical understanding and physics-based turbulence models will in turn result in unrefined and costly engineering designs. Predictive unsteady simulations such as direct numerical simulations (DNS) can provide detailed data that can be used to study critical turbulence phenomena and to develop physics-based turbulence models.

In this talk, I will first introduce a high-fidelity computational framework for DNS of high-speed turbulent flows. The numerical tool is capable of capturing flow features across a wide range of length and time scales, thus robust for a broad range of turbulent flow conditions, including flows containing shock waves and thermochemical non-equilibrium effects. The talk will then discuss an application of the DNS tool to characterize the freestream acoustic radiation from high-speed turbulent boundary layers. The study enabled the first digital simulation of the freestream acoustic disturbance environment in high-speed ground facilities – a groundbreaking achievement that has paved the way for improved ground-to-flight scalability of measurement data obtained in noisy wind tunnels. Finally, I will introduce our broader effort of developing a benchmark quality DNS database of supersonic/hypersonic turbulent boundary layers for refining and validating Reynolds-Averaged Navier-Stokes (RANS) models.