Abstract
The flow pattern around a rectangular cylinder were observed by the visualization used tracer technique and by L.D.V. in the uniform flow of Reynolds number lower than 10 3. Two different Strouhal numbers were found in the wake of the rectangular cylinder having width-to-height ratio of 5-8 at Re=890. Lower Strouhal number was caused by the vortex shedding from the side wall of the cylinder and higher one from trailing edges. The vortex shdding from the side wall seems to be the result of fluctuation of the shear layer separated from the leading edge. This vortex shdding from the side wall affected in the flow pattern of the wake at Re=890, but the influence of this vortex in the wake were weaker in the range of smaller Reynolds number.
