FREE-SURFACE FLOW GENERATED BY A SMALL SUBMERGED CIRCULAR-CYLINDER STARTING FROM REST

The impulsively starting motion of a small circular cylinder submerged horizontally below a free surface is studied analytically using a sma ll-time expansion. The cylinder is considered small if the ratio betwe en its radius and initial submergence depth is much smaller than one. The surface elevation is calculated up to third order. The hydrodynami c force on the small cylinder is also discussed. Certain inconsistenci es in our small-cylinder approximation (assuming locally uniform flow around the cylinder) are found in the force prediction. The present wo rk is an accompanying paper to Tyvand and Miloh (1995), where the same problem is studied for arbitrary radius versus submergence depth.