Umesh Unnikrishnan
(Advisors: Prof. Joseph C. Oefelein and Prof. Vigor Yang]

will propose a doctoral thesis entitled,

Subgrid Scale Modeling for Large Eddy Simulation of Supercritical Mixing and Combustion

On

Friday, December 4 at 2:00 p.m. (EST)

Bluejeans: https://bluejeans.com/395758928

Abstract
Advances in computing power have enabled opportunities for computational modeling and simulation to substantiate our understanding of fluid mixing and combustion in aerospace applications operating at extreme conditions. A prerequisite for effective use of numerical simulations in scientific research and development is high-fidelity and predictive capability of modeling and simulation techniques. Large eddy simulation (LES) is a powerful technique for research into turbulent flows and offers a favorable balance between high accuracy and computational feasibility. While the LES technique has been developed and applied over decades primarily in the context of low pressure, ideal gas conditions, its extension and application to complex, multi-physics flows in aerospace propulsion has remained under question. The strongly coupled non-linear physics of the governing multi-scale, physico-chemical processes in high pressure turbulent combustion lead to severe limitations and uncertainties in the application of the LES technique under conditions of practical interest. The scope of the proposed research is to investigate the theoretical and modeling framework for LES of compressible, multi-scalar turbulent mixing and combustion at supercritical pressures as encountered in liquid rocket engines and to establish a consistent and accurate approach for modeling the necessary physics.

In this thesis proposal, we present a systematic investigation of the LES governing equations using data from direct numerical simulation (DNS) of a liquid oxygen-methane mixing layer configuration at high pressure and high Reynolds number conditions. Data from these simulations are used to conduct a detailed analysis of the complete set of terms in the governing equations. A priori analysis of the current modeling approaches is conducted to investigate their accuracy as a function of grid resolution in this regime. Results obtained up to date are used to provide preliminary insights and a roadmap for the proposed research.

Committee

• Prof. Joseph C. Oefelein – School of Aerospace Engineering (advisor)
• Prof. Vigor Yang– School of Aerospace Engineering (co-advisor)
• Prof. Suresh Menon – School of Aerospace Engineering
• Prof. Timothy C. Lieuwen – School of Aerospace Engineering
• Dr. Ramanan Sankaran – Oak Ridge National Laboratory