The effect of plane wall on fluid forces acting on a circular cylinder

It is the purpose of this paper to make clear the change of fluid forces and pressure distribution along the surface of circular cylinder with the change of distance between circular cylinder and plane wall, and vortex shedding from a circular cylinder. We measured of fluid forces acting on a circular cylinder in the Reynolds number range of (10)^4 to 7×(10)^4 and pressure distribution along the surface of circular cylinder at the Reynolds number of 7×(10)^4. The following properties became evident often examining the experimental results. The Strouhal number calculated from the variation of lift in the region of spacing ratio Y/D=0~0.3 are nearly zero. The physical meaning of these fact is considered to be formation of separation region behind a circular cylinder. In region of the distance between a circuler cylinder and plane wall Y/D=0~0.7,position of stagnation point separation are influenced considerably by the spacing ratio. And in the case of Y/D>2,it can be consider that there is no effect of wall.