The secondary flow around an oscillating circular cylinder in a uniform flow

The secondary now around an oscillating circular cylinder in a uniform flow is investigated with the successive approximation of the Navier-Stokes equation for low Reynolds numbers, The approximation is based on the Oseen's one and the equation and the solution are expanded in the power series of the Reynolds number. It is shown that the secondary flow is obtained in the order of the square of the Reynolds number and directs to the upstream for low frequencies of the oscillation. The drag due to the secondary flow is expressed in the velocity and the oscillation amplitudes and takes positive values for low values of the Reynolds numbers and the frequencies.