Repository: Freie Universit├Ąt Berlin, Math Department

Diffraction of shock waves through a non-quiescent medium

Thethy, Bhavraj S. and Haghdoost, M.R. and Kirby, R. and Seo, B. and Nadolski, M. and Zenker, C. and Oevermann, M. and Klein, R. and Oberleithner, K. and Edgington-Mitchell, D. (2022) Diffraction of shock waves through a non-quiescent medium. Journal of Fluid Mechanics, 944 .

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Official URL: https://doi.org/10.1017/jfm.2022.484

Abstract

An investigation of shock diffraction through a non-quiescent background medium is presented using both experimental and numerical techniques. Unlike diffracting shocks in quiescent media, a spatial distortion of the shock front occurs, producing a region of constant shock angle. An example of this process arises in the exhaust from a pulse-detonation combustor. As the background velocity is increased, such as through the inclusion of a converging nozzle at the exhaust, the spatial distortion becomes more apparent. Numerical simulations using a compressible Euler solver demonstrate that the distortion is not due to the geometrical influence of the nozzle, but rather is a function of the magnitude of the background flow velocity. The distortion is studied using a modified geometrical shock dynamics formulation which includes the background flow and is validated against experiments. A simple model is presented to predict the shock distortion angle in the weak-shock limit. Finally, the axial decay behaviour of the shock is investigated and it is shown that the advection of the shock by the background flow delays the arrival of the head and tail of the expansion characteristic at the centreline. This leads to an increase in the rate of decay of the shock Mach number as the background flow velocity is increased.

Item Type:Article
Subjects:Mathematical and Computer Sciences > Mathematics > Applied Mathematics
Divisions:Department of Mathematics and Computer Science > Institute of Mathematics > Geophysical Fluid Dynamics Group
ID Code:2906
Deposited By: Ulrike Eickers
Deposited On:02 Mar 2023 09:56
Last Modified:02 Mar 2023 09:56

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