Turbulent Separation Around Cylinders in Waves

Abstract

The development of the turbulent boundary layer around a circular cylinder in oscillatory flow is investigated by the depth integrated equation of momentum. The shape of the velocity profile is assumed to be log‐linear. The development of the downstream separation point with time is studied as a function of the Keulegan‐Carpenter number and relative roughness for a rough cylinder, and as a function of the Reynolds number for a smooth cylinder. The paper suggests the parametric variation in the drag coefficient with the Reynolds number or relative roughness at small KC‐numbers (smaller than about 8–10) where vortex shedding does not take place.