Abstract
The stratified flow around a hemispheric obstacle on a flat plate has heen studied. The flows were produced by towing an inverted body through saline-water solutions with stable density gradients and were visualized by dye-injection method. The study demonstrated that three types of the flow structures were formed depending on the stratification. Two types of them are similar to the neutral cases but are strogly affected by the three-dimensional lee wave. In case of strongly stratified flow, most of the fluid cannot surpasses the hemisphere but passes around it and forms Karman vortex street behind the hemisphere. The change of the flow structure is closely related to the K-H instability in front of and behind a hemisphere.
