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Turbulence and Shear Flow Phenomena -1 First International Symposium

ISBN:
1-56700-135-1 (Print)

ASYMMETRIC RESPONSE OF TURBULENT CHANNEL FLOW TO WALL SUCTION AND BLOWING

Yongmann M. Chung
School of Engineering and Centre for Scientific Computing University of Warwick Coventry CV4 7AL, UK

Hyung Jin Sung
Department of Mechanical Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon 305-701, Korea

Abstract

A direct numerical simulation was performed to investigate the effects of spatially-varying wall suction and blowing on turbulent channel flow. Two combinations of wall suction and blowing were considered: one is a sequence of suction and blowing (S-B) and the other is a sequence of blowing and suction (B-S). A sinusoidal form of wall suction and blowing was applied at the lower wall of the channel through a spanwise slot, downstreeam of which the flow was allowed to adjust itself to a new boundary condition at the impermeable wall. The main emphasis was placed on the asymmetric response of wall-bounded turbulent flow to different sequencies of wall suction and blowing. The rate of adjustment and the relaxations after local actuations were evaluated. It was found that the time-mean velocity and Reynolds stresses were modified significantly depending on the sequences.