ARTICLE:

• DNS of Heat Transfer in a Transitional Channel Flow Accompanied by a Turbulent Puff-like Structure  download article

T. Tsukahara
Department of Mechanical Engineering, Tokyo University of Science, Noda-shi, Chiba 278-8510, Japan

K. Iwamoto
Department of Mechanical Engineering, Tokyo University of Science, Noda-shi, Chiba 278-8510, Japan

H. Kawamura
Department of Mechanical Engineering, Tokyo University of Science, 278-8510 Chiba, Japan

T. Takeda
Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, Oarai-machi, Higashi Ibaraki-gun, Ibaraki 311-1393, Japan

ABSTRACT

Direct numerical simulation of heat transfer in a fully developed channel flow has been carried out in a range of low Reynolds numbers from Re_τ = 180 down to 60 (based on the friction velocity and the channel half width δ) with emphasis on a puff-like structure. For Re_τ ≤ 80 with the largest computational domain of 51.2δ × 2δ × 22.5δ, the turbulent puff is observed and significantly affects the momentum and heat transports. The spatial structure of the equilibrium puff is examined with taking account of two different thermal boundary conditions. It is revealed that there exists a localized strong turbulent region, in which a secondary flow is induced by the puff. In consequence, at the present lowest Reynolds number as low as Re_τ = 60, the flow remains turbulent and the larger Nusselt numbers than those without puff is obtained.

 download article

193-196 pages

« Previous article         Next article »