Turbulent Mixed Convection Flow Over a Backward-Facing Step-The Effect of Step Heights

Abstract

Effect of the backward-facing step heights on turbulent mixed convection flow along a vertical flat plate is examined experimentally. The step geometry consists of an adiabatic backward-facing step, an upstream wall and a downstream wall. Both the upstream and downstream walls are heated to a uniform and constant temperature. Laser-Doppler velocimeter and cold wire anemometer were used, respectively, to measure simultaneously the time-mean velocity and temperature distributions and their turbulent fluctuations. The experiment was carried out for step heights of 0, 11, and 22 mm, at a free stream air velocity, u∞, of 0.41 m/s, and a temperature difference, ΔT, of 30 °C between the heated walls and the free stream air. The present results reveal that the turbulence intensity of the streamwise and transverse velocity fluctuations and the intensity of temperature fluctuations downstream of the step increase as the step height increases. Also, it was found that both the reattachment length and the heat transfer rate from the downstream heated wall increase with increasing step height.

Department(s)

Mechanical and Aerospace Engineering

Sponsor(s)

National Science Foundation (U.S.)
Purdue University

Keywords and Phrases

Backward-Facing Step Heights; Turbulent Mixed Convection Flow; Vertical Flat Plate

International Standard Serial Number (ISSN)

0142-727X

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2002 Elsevier, All rights reserved.

Publication Date

01 Dec 2002

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