ドラム型遠心力載荷装置における水面波の造波

Abstract

The generation and propagation of gravity surface waves in a drum centrifugeis discussed, with application to seabed mechanics. The dispersion relationships ofthe surface gravity waves in rotating fluids are derived with due consideration ofthe Corliolis effect. They clearly indicate that a forward wave at a givenwavelength has a larger phase-velocity, compared with a backward wave with thesame wavelength.An approximate theory of wave-making is developed, with reference to themethod of rapidly immersing a float of rectangular section into water in a rotatingdrum. The interaction between the motion of the float and the generated wavesgoing sideways, is formulated. The nonlinear drag resistance also is allowed for.The theory successfully predicts that the float-water system forms a highly dampedsystem owing largely to the radiation damping. The theory also gives a workablewaveform in the source region.It is found from Test WAVE 12 that the wave-induced porewater pressures infine sand exhibit marked phase-lag, compared with the water pressure measured justabove the sand surface.