Experimental study on the hydrodynamic characteristics of cylinder with rough surface

The main purpose of this study is to establish a better understanding of the relationship between the hydrodynamic characteristic and cylinder with rough surface. Experiments were conducted to measure the force and the hydrodynamic efficient of a circular cylinder with different types of artificial rugged surface. The relative roughness coefficient ranged from k / D = 0.00005–0.02 ( k is the roughness height, D is the outer diameter of cylinder) is used to evaluate the rough surface of experiment model. Wave and current experiments are conducted in the wave tank. Results show that relative roughness indeed plays an important role in affecting the hydrodynamic characteristic on the cylinder. For the drag coefficient ( C d ) in current experiment, C d enlarges a lot under the effect of rough surface compared with smooth cylinder and has a regular change with relative roughness. For the inertia coefficient ( C M ) in wave experiment, C M is greatly affected by the rough cylinders for small KC numbers. For the C d in wave experiment, it is greatly affected by large rough cylinders.