Indian Journal of Science and Technology

Abstract

The Effect of freestream velocity and Ellipticity ratio on the similarity distribution of the static pressure along the wake axis of the elliptic cones is presented. A cone of elliptic cross section produces separated flow at the downstream of its base. Within the separated region the flow is observed to be opposite (reverse) to the main outer flow. To obtain the length of reverse flow region, magnitude and location of maximum reverse velocity and re attachment point knowledge of pressure distribution behind a body is essential. Experiments were carried out for three different test section freestream velocities 6m/s, 15m/s and 25 m/s (Reynolds numbers 0.16 x 105, 0.4 x 105 and 0.667 x 105 based on cone effective diameter respectively). Ellipticity ratio 1 and 3 with constant fineness and bluntness ratio of 2.75 and 0.049 respectively were considered for the experiments. A Digital Sensor Array –DSA was used for static pressure measurements. The pressure sensor has the capability of 1 PSI differential pressure range with +/- 0.12% full-scale accuracy. Good similarity in wake axis static pressure distribution is noted for different freestream velocity behind a circular cone. But, Similarity in pressure distribution is not observed along the wake axis of an elliptic cone at tested lower freestream velocity (6 m/s).

Keywords: Elliptic Cone, Pressure Coefficient and Similarity Parameter, Wake Pressure