Title: Breakdown of similarity between momentum and energy transfer in a stagnation-region with free-stream turbulence

Authors: Sungwon Bae, Hyung Jin Sung

Addresses: Development Team, PDP Division, Samsung SDI Co. Ltd, Cheonan City, 330 300, Korea. ' Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 373 1, Guseong-dong Yuseong-gu, Daejeon, 305 701, Korea

Abstract: A direct numerical simulation of turbulent stagnation-region heat transfer with free-stream turbulence is performed. The temperature field in the |damping| regime is mildly disturbed and that in the |attached amplifying| regime is organised. In the |detached amplifying| regime, the temperature field becomes turbulent. The temperature field is stretched in the x direction near the wall. The surface contours reveal that the temperature field is influenced significantly by streamwise vorticity. The enhancement of wall heat transfer by free-stream turbulence is similar to that in the previous results of the organised inflow disturbances. This indicates that the effect of large-scale eddies on the enhancement of wall heat transfer is important in the turbulent stagnation-region heat transfer. The breakdown of similarity between momentum and energy transfers in the stagnation-region with free-stream turbulence is analysed. The wall blocking and the pressure fluctuations are found to be responsible for the dissimilarity.

Keywords: direct numerical simulation; DNS; stagnation-region heat transfer; free-stream turbulence; inflow disturbance; similarity breakdown; CFD; computational fluid dynamics; turbulent flows; wall heat transfer.

DOI: 10.1504/PCFD.2006.009479

Progress in Computational Fluid Dynamics, An International Journal, 2006 Vol.6 No.1/2/3, pp.21 - 32

Published online: 05 Apr 2006 *

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