0n a Stern Flow Field with Bildge Vorticies

Abstract

Recently many people investigated the velocity distribution around the ship stern and found the very complicated shapes of equi-velocity contours and longitudinal vorticity component. They guess that 3-d separation and the roll-up of vortex layer occur near the stern in combination with the flow visualization. The theoretical investigation is also made but sometimes calculation was diverged away in most part of the stern flow field. In this paper, (1) the velocity distribution is investigated experimentaly by use of a small 5-hole pitot tube in detail, and (2) based on its result, we propose a theoretical method to predict the velocity distribution around the ships tern. Numerical calculation is made along the local streaming flow direction and the velocity defect components are calculated simultaneously. The calculation is continued step by step under the assumptions that the fluid is inviscid but rotational Obtained results show similar tendencies with experimental results.