Mechanical and Civil Engineering Seminar

Mechanical and Civil Engineering Seminar Series

Title: Efficient wave-appropriate numerical methods for high-speed compressible flow simulations

Abstract: In this talk, I will present novel numerical methods for simulating high-speed compressible flows, emphasizing applications in high-speed multicomponent and multiphase flow regimes. The presentation is divided into two parts. In the first part, I will introduce the Gradient-Based Reconstruction (GBR) technique, which enables accurate and efficient computation by reusing gradients across both convective and viscous flux evaluations within a finite volume framework. The GBR approach reconstructs cell interface values using cell-centered quantities and their gradients, providing a compact and modular approach. The technique is compatible with problem-independent shock-capturing strategies, and I will demonstrate its performance on a range of benchmark test cases. In the second part, I will present a wave-appropriate discretization strategy for compressible flow simulations. Compressible flows are characterized by multiple physical phenomena—shocks, contact discontinuities, and turbulence—each requiring tailored numerical treatment. Conventional methods typically address all these features with one scheme, often leading to accuracy or excessive dissipation compromises. Our approach leverages the wave structure of the Euler equations to design wave-appropriate discretizations. This approach enabled coarse grid hypersonic boundary layer transition simulations using Wall-Modeled Large Eddy Simulations (WMLES) and low-dissipation multicomponent and multiphase flow simulations.

Bio: Dr. Sainadh Chamarthi is a postdoctoral fellow at the California Institute of Technology, Pasadena, CA. Before that, Sainadh was a postdoctoral fellow at Technion, Israel, where he developed a variety of low-dissipation and high-resolution numerical methods for compressible flows featuring high-speed boundary layer transition, multicomponent flows, and shock-shock interactions. Sainadh graduated with a PhD in the Department of Aeronautics and Astronautics from the University of Tokyo, working on numerical modelling of spacecraft propulsion systems. Sainadh received the Japanese government scholarship (MEXT) during his PhD program. Before his graduate studies, he was a Scientist at the Indian Space Research Organization, working on rocket propulsion, crew escape system design, Hall thrusters, etc. His research interests include computational modelling of high-speed compressible flows, multicomponent flows, external aerodynamics, development of novel high-order methods, and high-performance computing.

NOTE: At this time, in-person Mechanical and Civil Engineering Lectures are open to all Caltech students/staff/faculty/visitors.