Boundary layer flow over long cylinders with suction

The possibility of using wall suction to reduce the drag in a flow over a semiinfinite cylinder is explored by means of an analytical approximation. The solution involves successive differentiation of the known Iglisch (1949) wall compatibility condition. The solution is applied to a zero-suction condition, exibiting good agreement with available sophisticated techniques. An optimal suction profile is found as a function of free-stream conditions and cylindrical fineness ratio. The analysis reveals that by withdrawing relatively small amounts of fluid from the boundary layer the flow can be kept laminar at high Reynolds numbers, resulting in considerable decreases in drag, with potential applications to aircraft fuselages and underwater vehicles.