Transient energy growth modulation by temperature dependent transport properties in a stratified plane Poiseuille flow

Conference paper (2015)
Department
Process and Energy (Mechanical, Maritime and Materials Engineering) (TU Delft)
Copyright: © 2015 the Authors
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Published Date

28-08-2015

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Source:

15th European Turbulence Conference 2015 (ETC15), August 25-28th, 2015, Delft, The Netherlands

Faculty

Mechanical, Maritime and Materials Engineering

Department

Process and Energy

Abstract

We investigate the effect of temperature dependent thermal conductivity ? and isobaric specific heat c_P on the transient amplification of perturbations in a thermally stratified laminar plane Poiseuille flow. It is shown that for decreasing thermal conductivity the maximum transient energy growth is amplified with respect to the ?=1 case, while the opposite occurs for increasing ?. A reversed mechanism is induced by a variable c_p. Substantial maximum growth enhancement/suppression is found in the range of Prandtl numbers Pr which encompasses most fluids of practical interest. The relative growth modulation shows an optimum Pr under spanwise perturbations. For energy amplifying property distributions a speed-up of the transient to reach the maximum energy growth is observed at low Pr, while a slow-down is found at large Pr. The opposite is true when the property variations suppress the growth of perturbations.

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