Vortex-Induced Vibrations due to Steady and Wave-Induced Currents of a Flexible Cylinder Near a Plane Boundary

Abstract

Model tests were performed in a wave tank to determine the effect of combined steady and wave-induced currents and/or proximity of a plane boundary (seabottom) on the vortex-induced vibrations of a flexible pipe. The first mode response of the pipe in both the transverse and in-line directions was measured using a biaxial accelerometer positioned inside the pipe at the midpoint of its span. Results are presented for a wide range of steady flow velocities with superimposed wave-induced flow corresponding to Keulegan–Carpenter numbers of 0, 5, 10, 15, 20, 25 and 30 and pipe-to-wall gaps of 1, 2, 4, 6 and ∞ (isolated pipe) pipe diameters.