Department of Mechanical Engineering, Engineering faculty, Bozorgmehr University of Qaenat, Qaen, Iran
Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
The current empirical study was conducted to investigate the wall neighborhood impact on the two-dimensional flow structure and heat transfer enhancement behind a square cylinder. The low- velocity open-circle wind tunnel was used to carry out the study tests considering the cylinder diameter (D)-based Reynolds number (ReD) of 5130. The selected items to compare were different gap height (G/D= 0.0, 0.1, 0.2 and 0.8). The flow field was measured using particle image velocimetry (PIV) with high image-density camera. The PIV-derived time-averaged quantities, including the streamline pattern, streamwise velocity fluctuation intensity, and reverse-flow intermittency, were examined for the flow past the square cylinder. The measurements of PIV were decomposed with the help of proper orthogonal decomposition (POD) approach that provides a proper view of the POD modes. To obtain the value of the heat transfer enhancement behind the square cylinder, the full-field temperature distributions of flat plate were measured through the temperature-sensitive paint (TSP) technique. Results showed that the maximum heat transfer enhancement was obtained at G/D=0.2 due to the high unstable flow near the wall.