Mississippi State University
Date of Degree
Dissertation - Open Access
Doctor of Philosophy
James Worth Bagley College of Engineering
Department of Mechanical Engineering
Temporally developing direct numerical simulations (T-DNS) are performed and validated for bypass transition of a zero pressure gradient flat plate boundary layer to understand the interplay between pressure-strain terms and flow instability mechanisms, and to propose and validate a phenomenological hypothesis for the identification of a robust transition onset marker for use in transition-sensitive Reynolds-averaged Navier-Stokes (RANS) computational fluid dynamics (CFD) simulations. Results show that transition initiates at a location where the slow pressure-strain term becomes more dominant than the rapid term in the pre-transitional boundary layer region. The slow pressure strain term is responsible for the transfer of turbulence energy from the streamwise component to other components while the rapid pressure strain term counteracts with the slow term in the pre-transitional regime before transition onset akin to a shear sheltering like effect. The relative magnitudes of the slow and rapid terms thus provide a basis for the development of physically meaningful large-scale parameters that can be used as a transition onset marker for Reynolds averaged Navier-Stokes RANS simulations.
NASA EPScoR Project Number 80NSSC17M0039, CAVS
Muthu, Satish, "Phenomenological identification of bypass transition onset markers using temporal direct numerical simulation of flat plate boundary layer" (2020). Theses and Dissertations. 3526.