Experimental study of wave kinematics and wave load distribution on a vertical circular cylinder

In this paper, we present measurements of force distribution on a vertical, circular cylinder exposed to shoaling regular waves. The cylinder was divided into four individual sections on which the wave loads were measured. Furthermore, we measured the wave kinematics with Particle Image Velocimetry (PIV) and with Laser Doppler Velocimetry (LDV) in a few reference cases. The force distribution was measured for twenty regular wave conditions and in all the cases the maximum force did not occur simultaneously on the individual sections of the cylinder. A decomposition of the total force in force harmonics showed the same tendencies for the total force as presented in literature. A decomposition of the force on individual cylindrical sections showed that the section at the surface had a significantly higher second force harmonic compared to the sections closer to the bed. Furthermore, we studied the local force coefficients on the individual sections on the cylinder. The inertia coefficient exhibited the same trend for all the individual sections. Estimated force coefficients from measured wave kinematics corresponded well with force coefficients in the literature.