Author

Satish Muthu

Advisor

Bhushan, Shanti

Committee Member

Li, Like

Committee Member

Sescu, Adrian

Committee Member

Lv, Yu

Date of Degree

8-1-2020

Document Type

Dissertation - Open Access

Major

Mechanical Engineering

Degree Name

Doctor of Philosophy

College

James Worth Bagley College of Engineering

Department

Department of Mechanical Engineering

Abstract

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.

URI

https://hdl.handle.net/11668/18046

Sponsorship

NASA EPScoR Project Number 80NSSC17M0039, CAVS

Comments

Bypass Transition||Transition Markers||Transition Onset||Direct Numerical Simulation||Pressure-Strain Correlation||Temporally Developing DNS||Flat-Plate Boundary Layer

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