Abstract
For the flow of a fluid at low Reynolds numbers around a circular cylinder, some experimental and theoretical investigations have been made up to the present. But the clear photographs of the flow patterns which serve as a verification or guidance of the theories seem to be in relatively lack. The low Reynolds number flows around a circular cylinder were photographically investigated using the aluminum dust flow visualization technique. From many photographs of the flow patterns at Reynolds numbers from 0.35 to 12.8 were investigated the variation of flow patterns with Reynolds number, the critical Reynolds number for the appearance of standing twin-vortices behind a circular cylinder and the effect of the Reynolds number on the growth in size of the standing twin-vortices.
