Affiliation:
1. Department of Mechanical Aerospace Engineering and Engineering Mechanics, University of Missouri-Rolla, Rolla, MO 65401-0249
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.
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics,General Materials Science
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