Laminar Natural Convection Flow Over a Vertical Backward-Facing Step

Abstract

Measurements and predictions of laminar boundary-layer air flow in natural convection over a vertical two-dimensional backward-facing step are reported. The upstream and downstream walls and the step itself were heated to a uniform and constant temperature. The experiment was carried out for the ranges of step heights 3.5 mm ≤ s ≤ 9 mm, temperature differences of 5.8°C ≤ ΔT ≤ 23°C between the heated wall and the free stream (corresponding to 2.238 × 107 < Grxi < 8.877 × 107), and reference velocities of 0.24 m/s ≤ u* ≤ 0. 47 m/s. Laser-Doppler velocimeter and cold-wire anemometer were utilized to measure, respectively, the velocity and the temperature distributions simultaneously. Flow visualization was also performed to determine the reattachment length. Measurements compare favorably with predictions. These results reveal that the step height significantly affects the velocity and temperature distributions, the friction coefficient, and the rate of heat transfer downstream of the backward-facing step.

Department(s)

Mechanical and Aerospace Engineering

International Standard Serial Number (ISSN)

0022-1481

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 1995 American Society of Mechanical Engineers (ASME), All rights reserved.

Publication Date

01 Jan 1995

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