Inscrição na biblioteca: Guest
TSFP DL Home Arquivos Comitê executivo

MOMENTUM AND HEAT TRANSPORT IN THE WAKE OF TWO TANDEM CYLINDERS

G. Xu
Department of Mechanical Engineering The Hong Kong Polytechnic University Hung Hom, Kowloon, Hong Kong

Yu Zhou
Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong; Institute for Turbulence-Noise-Vibration Interaction and Control Shenzhen Graduate School, Harbin Institute of Technology Shenzhen, 518055, China

Resumo

The vortex structures, momentum and heat transport in the wake of two tandem circular cylinders have been investigated. The measurements were conducted at x/d = 10 ~ 30 and Re (≡ Ud/ν, where d is the cylinder diameter, U the free stream velocity and ν the kinematic viscosity) = 7000 using a three-wire (an X-wire plus a cold wire) probe, in conjunction with an X-wire. The cylinder center-to-center spacing, L/d, was 1.3, 2.5 and 4, each representing one typical flow regime. The regimes are classified based on whether the shear layers separated from the upstream cylinder form vortices between the cylinders, reattach on or roll up behind the downstream cylinder (without reattachment). The phase-averaged sectional streamlines and vorticity contours display a single vortex street behind the downstream cylinder, irrespective of different flow regimes. However, the flow structure does depend upon L/d in terms of longitudinal and lateral vortex spacing, vortex strength and the downstream decay of vorticity. The momentum and heat transport characteristics of the flow are discussed by examining the coherent and incoherent momentum and heat flux vectors.