Water Forces on Accelerated Cylinders

The economical design of fixed structures immersed in ocean waves or other oscillating fluid masses is handicapped by an insufficiency of data. statistical studies based on wave records collected in many parts of the world provide an estimate of the heights and steepnesses of waves which may be expected at a given site during a specific period of years. From these wave parameters and the depth of the water, the designer must compute the forces on the structures.

This paper deals with the forces exerted by water on an immersed, horizontally mounted, circular cylinder, which was moved in a horizontal direction normal to its long axis. The accelerations and velocities were in the range common to ocean waves. Both constant and variable linear accelerations and decelerations were used to discover possible effects of acceleration and rates of change of acceleration. Three diameters were used to cover the range of Reynolds numbers from the Karman vortex region through the boundary layer transition region. The regions of over lapping of the data permitted observation of the effects of diameter at constant Reynolds number. By towing another similar cylinder parallel to the test cylinder, some of the effects of a neighboring cylinder were investigated.