PIV and TSP Measurements of Boundary Layer distributed by a Square Cylinder
Effect of wall proximity on the flow structure and heat transfer enhancement behind a two-dimensional square cylinder was studied experimentally in the present work. The experiments were performed in the subsonic open-circuit wind tunnel, and Reynolds number based on the cylinder width (D) was kept at ReD= 5130. Four cases with different gap widths, namely G/D = 0.0, 0.1, 0.2 and 0.8, were chosen for comparison. PIV with high image-density camera was employed for flow field measurement. The flow behind the square cylinder was analyzed in terms of time-averaged quantities measured by PIV, i.e., the streamline pattern and reverse-flow intermittency. Also, the temperature sensitive paint (TSP) method was applied for determination of temperature distribution of the flat plate, presenting value of the heat transfer enhancement behind the square cylinder. Results showed that the maximum heat transfer enhancement was obtained for G/D=0.2 due to the high unstable flow near the wall.
Keywords - Heat transfer Coefficient, Reverse flow, unstable flow, Reattachment point