Influence of Knudsen and Mach numbers on Kelvin-Helmholtz instability

Vishnu Mohan, A Sameen, Balaji Srinivasan, and Sharath S. Girimaji

Phys. Rev. E 103, 053104 – Published 14 May 2021

Abstract

The combined influence of rarefaction and compressibility on classical Kelvin-Helmholtz instability is investigated with numerical simulations employing the unified gas kinetic scheme. Five different regimes in the Reynolds-Mach-Knudsen number parameter space are identified. The flow features in various Mach and Knudsen number regimes are examined. Stabilizing action of compressibility leads to suppression of perturbation kinetic energy and vorticity and/or momentum thickness. The suppression due to rarefaction exhibits a different behavior. At high enough Knudsen numbers, even as the perturbation kinetic energy is suppressed, the vorticity and/or momentum thickness grows. The flow physics underlying the contrasting mechanisms of compressibility and rarefaction is highlighted.

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Received 31 December 2020
Accepted 26 April 2021
Corrected 24 May 2021

DOI:https://doi.org/10.1103/PhysRevE.103.053104

Physics Subject Headings (PhySH)

Compressible flows Kelvin-Helmholtz instability

Fluid Dynamics

Corrections

24 May 2021

Correction: The omission of a support statement in the Acknowledgments has been fixed.

Authors & Affiliations

Vishnu Mohan ^* and A Sameen ^†

Department of Aerospace Engineering, Indian Institute of Technology Madras, Chennai 600036, India

Balaji Srinivasan^‡

Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600036, India

Sharath S. Girimaji^§

Department of Ocean Engineering, Texas A&M University, College Station, Texas 77843, USA

^*Present address: Department of Aerospace Engineering, Indian Institute of Technology Madras, Chennai-600036, India; ae16d421@smail.iitm.ac.in
^†sameen@ae.iitm.ac.in
^‡sbalaji@iitm.ac.in
^§girimaji@tamu.edu

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Issue

Vol. 103, Iss. 5 — May 2021

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Physical Review E

covering statistical, nonlinear, biological, and soft matter physics