Instant tsunami bore pressure and force on a cylindrical structure

This study investigates tsunami bore impact on a cylindrical structure. A physical study was carried out in a large wave flume with a horizontal floor. Experiments covered a range of bore heights (140-210 mm) and bore velocities (1.98-2.45 m/s). The vertical and angular distributions of the applied pressure were measured using a vertical array of pressure sensors. The cylindrical structure was rotated so that the sensors were orientated at several angles between 0° and 135°, giving in effect a three-dimensional pressure distribution around the structure. The total stream-wise force was computed as a summation of the hydrostatic and hydrodynamic forces. A hydrodynamic coefficient of 0.65 was found to be appropriate for this study. The height of the centre of effort of the force on the cylinder surface was estimated by dividing the measured moment by the measured force, and was found to be proportional to the actual water height at the front face of the cylinder.