Modelling of Turbulent Mean Flow and Perturbations for High-speed Compressible Flows

Turbulence prediction constitutes a critical bottleneck plaguing numerous engineering applications including aircraft, aero-engines and hypersonic vehicles. Compared to the low-speed counterparts, high-speed compressible turbulence models currently rest on weaker theoretical foundations and exhibit notable prediction errors under the wall cooling condition required for thermal protection. On the other hand, resolving turbulent structures is critical to understanding turbulence and guiding model development. Compared with direct numerical simulation (DNS) and high-quality experimental measurements, resolvent linear models represent an efficient pathway for investigating turbulent structures and control, rendering them a prominent research frontier in recent years. Nevertheless, most such models are developed for low-speed flows and lack sufficient accuracy when applied to high-speed turbulence.

In this talk, we present an inverse transformation framework to achieve accurate prediction of the mean velocity and temperature in canonical turbulent flows with Mach numbers from 2 to 14. Novel wall models for velocity and temperature are proposed, enabling systematic improvements to algebraic turbulence models. Moreover, we improve stochastic and resolvent linear models for compressible turbulence and verify their mathematical self-consistency. Using solely the mean flow as the input, the spectral scaling and inner-outer interaction of multi-scale coherent structures are well predicted across a broad range of Mach and Reynolds numbers, far exceeding the parameter ranges of existing DNS datasets.

Dr Xianliang Chen currently serves as a Research Assistant Professor at the Hong Kong University of Science and Technology. He is going to serve as one of the faculty members in Tsinghua University. He earned his BEng and PhD degrees from Tsinghua University, where he was recognized as an Outstanding Graduate. His research focuses on boundary layer instability and wall-bounded turbulence, and he has authored more than 20 journal articles. He is the Prinicipal Investigator of the NSFC Excellent Young Scientists Fund (Overseas). His academic awards include the Outstanding Doctoral Dissertation Award from the Chinese Society of Aeronautics and Astronautics, the Outstanding Young Scientist Award at the 14th IWMO conference, and the Zijing Scholar Fellowship at Tsinghua University.