Model experiments of hydrodynamic forces on heave plates

For truss SPAR platforms, damping plates are employed to increase the added mass and viscous drag in the heave direction. The paper aims to investigate experimentally the hydrodynamic forces on heave plates with different opening sizes. Model scale experiments were carried out on three 40 by 40cm flat plates to investigate the effects of oscillation amplitude and opening size on the hydrodynamic forces acting on the plates whilst undergoing forced heave motion. Three different methods of data processing were investigated, namely, directly processing unfiltered data to obtain the hydrodynamic coefficients, filtering the data before evaluating the coefficients and fitting the filtered data to a sine curve before evaluating the coefficients. The most accurate method was then selected and used to evaluate the experiment results. The coefficient values obtained were compared with the published data available. The effects of various variables such as opening size, KC number, frequency of oscillation on the hydrodynamic coefficients were also studied. Relative magnitudes of the drag and inertia components of the overall hydrodynamic load are compared.