Flow Field around a Blunt-nosed Body with Spike

Abstract

The zone of influence and the positive pressure field over the nose, for a blunt-nosed body, with and without spike, were measured by direct means. Flow past the body, with and without spikes, was visualized in a two-dimensional water channel, at a specific Reynolds number. It is found that, the spike reduces the radius of curvature of the approaching streamline, and the deflection of the streamline is towards the shoulder of the basic body, resulting in a narrow zone of the positive pressure hill at the nose. The spike with hemispherical nose reduces the zone of influence drastically from 1.75 to less than 1.60. The pressure hill height for hemispherical nose is found to be smaller, compared to other shapes of the spike nose studied. The hill heights for the flat faced spike with cylindrical and square stems are comparable. It is found that, the size of the vortex at the junction of the spike and basic body is the largest for the hemispherical nose.