PREDICTION OF VELOCITY AND THERMAL BOUNDARY LAYERS OF HIGHLY TURBULENT AIRFLOW OVER HEATED FLAT PLATE

摘要

The paper investigates computationally the effect of highly turbulent free air stream on.the boundary layer behavior of heated flat plate. The flow Reynolds number is chosen to be low (3 x10~4 ≤ Re_x ≤ 8 x 10~5). This is accomplished through a compressible boundary layer code. The turbulence model used is the standard Jones-Launder k-ε low Reynolds number version. This work is divided into three phases; the first is to verify and validate the code with available experimental data. The second phase studies the velocity and thermal boundary layer for limited temperature difference between the plate and air. The third phase is concerned with highly turbulent air as it passes over heated plate of significant temperature difference. In the last case, the properties of air are assumed dependent on its temperature. This study shows that increasing the temperature difference, skin friction coefficient and shape factor increase while Stanton number decreases. Moreover, the thermal and velocity boundary layers change in shape with decreasing in their gradient near the wall.