Aerodynamic forces on a square cylinder in oscillating flow with mean velocity

Unsteady forces acting on a square cylinder in oscillating flow with nonzero mean velocity are measured. The oscillating air flows are generated by a unique AC servomotor wind tunnel. The generated velocity histories are almost exact sinusoidal waves. The measured unsteady forces are examined in relation with the Morison equation and the contribution of the inertia term. It is confirmed that the Morison equation is applicable to explain the present experimental results. The fluid force coefficients, including the inertia coefficients, are evaluated for both in-line and transverse forces.