Volume 21, Issue 2 (June 1998)
Generation of Progressive Fluid Waves in a Geo-Centrifuge
This paper describes a practical way of generating progressive fluid waves in a wave tank of limited length that may be readily mounted on a geo-centrifuge. The wave tank developed features a quasi-flap-type wavemaker, a sediment trench, and a slotted vertical partition that was placed in the wave channel for wave absorption purposes. A comprehensive series of centrifugal wave tests with either water or silicone oil of scaled viscosity showed that, for a slotted-area ratio of 0.3, the reflection coefficient of the slotted partition became as low as 0.13, thereby giving rise to essentially progressive waves. The optimal distance behind the partition to the far end of the wave channel was found to be equal to approximately a quarter wave length of the incident waves.
This led to the second stage of experimentation in which fine-grained sand beds were subjected to a range of essentially progressive waves, with viscous scaling introduced. The results of the centrifugal wave tests showed that, when subjected to severe waves, the sand beds underwent liquefaction, resulting in a complete loss of effective stress due to the buildup of residual pore pressures.