Apparatus and Instrumentation

A setup for conducting experiments where wake properties of a square cylinder can be studied has been constructed in the laboratory. The setup resembles a low speed wind tunnel, though smaller in the overall size. It is a vertical test cell made of Plexiglas with two optical windows, one for laser sheet and the other for recording images by the CCD camera. The working fluid is air and the direction of overall fluid motion is in the vertically upward direction. Particle Image Velocimetry (PIV) and Hotwire Anemometry (HWA) have been primarily used for velocity measurements. Flow visualization study has been carried out at low seeding density in the PIV setup. The cylinder is oscillated with the help of an electromagnetic actuator. This module describes details of the experimental hardware, including instruments and auxiliary equipment used in the present study. The validation results for proper PIV technique implementation, flow parallelism and turbulence intensity of the test cell and the effect of end plates have been discussed.