Observation of a Vortex in Front of a Half-Submerged Circular Cylinder

抄録

Experimental evidence is reported that a two-dimensional vortex is formed in front of a half-submerged circular cylinder, which is supported horizontally near the surface of water in a towing tank and moved in the direction normal to its axis. The experiment was mode at Reynolds numbers (based on the velocity and the radius of the cylinder) less than about 5×10³. The upstream vortex seems to be due to the forward movement of the surface layer of water driven by the cylinder.