Threedimensional simulations of large eddies in the compressible mixing layer
Sandham, N.D. and Reynolds, W.C. (1991) Threedimensional simulations of large eddies in the compressible mixing layer Journal of Fluid Mechanics, 224, pp. 133158. (doi:10.1017/S0022112091001684).
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Description/Abstract
The effect of Mach number on the evolution of instabilities in the compressible mixing layer is investigated. The full timedependent compressible Navier–Stokes equations are solved numerically for a temporally evolving mixing layer using a mixed spectral and highorder finite difference method. The convective Mach number Mc (the ratio of the velocity difference to the sum of the freestream sound speeds) is used as the compressibility parameter. Simulations with random initial conditions confirm the prediction of linear stability theory that at high Mach numbers (Mc > 0.6) oblique waves grow more rapidly than twodimensional waves. Simulations are then presented of the nonlinear temporal evolution of the most rapidly amplified linear instability waves. A change in the developed largescale structure is observed as the Mach number is increased, with vortical regions oriented in a more oblique manner at the higher Mach numbers. At convective Mach numbers above unity the twodimensional instability is found to have little effect on the flow development, which is dominated by the oblique instability waves. The nonlinear structure which develops from a pair of equal and opposite oblique instability waves is found to resemble a pair of inclined Avortices which are staggered in the streamwise direction. A fully nonlinear computation with a random initial condition shows the development of largescale structure similar to the simulations with forcing. It is concluded that there are strong compressibility effects on the structure of the mixing layer and that highly threedimensional structures develop from the primary inflexional instability of the flow at high Mach numbers
Item Type:  Article  

Digital Object Identifier (DOI):  doi:10.1017/S0022112091001684  
ISSNs:  00221120 (print) 

Subjects:  
ePrint ID:  72047  
Date : 


Date Deposited:  18 Jan 2010  
Last Modified:  18 Apr 2017 20:58  
Further Information:  Google Scholar  
URI:  http://eprints.soton.ac.uk/id/eprint/72047 
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