Measurement of Cable Support Point Motions Due To Vortex-Induced Vibrations

Fiber-optic technology has created the opportunity for the development of underwater communications cables which are much smaller than those used in the past. These new cables will be more vulnerable to environmental damage then their predecessors. One form of environmental damage which may lead to system failure is abrasion at cable suspension supports caused by vortex-induced vibration of the cable span. To assess the threat of undersea cable failure due to abrasion caused by vortex-induced vibrations, a series of experiments were conducted in which a length of vertical cable with a clump weight at the lower end was suspended over various frictional supports and towed through quiescent water. The objective of the experiments was to measure magnitude of the cable motions at imperfect supports during resonant vortex-induced vibrations of the cable span.