Motivated by observations of fluid mud mixing under surface wave motion, this study presents a scenario wherein the prevailing modeling of fluid mud transport fails to estimate entrainment under surface wave action. In this situation, the fluid mud layer is susceptible to resonance-generated interfacial instabilities. The aim of this work is to assess the performance of traditional sediment entrainment models under this condition and to provide a simple framework for handling it. To address this, a series of experiments were conducted in a wave flume with a surface wave propagating over a layer of fluid mud. Following the initiation of surface wave motion, interfacial instabilities emerged as a three-dimensional quasi-standing wave through a resonant interaction with the surface wave. As the amplitude of this interfacial wave increased, significant mixing between the fluidized sediment bed and overlaying clear water ensued in the wave flume. The quantity of entrained mud particles in the clear water at the conclusion of each experiment was measured and compared with the predictions of a widely used fluid mud entrainment model. It was found that the model, which considers only interfacial instabilities arising from surface wave-induced shear rate at the bed, significantly underestimates fluid mud entrainment. The model was then refined to account for the effects of shear rate produced by the resonantly generated interfacial instability. Results show that the modified framework can accurately predict the sediment resuspension by the resonant interfacial instability.
Aleebrahim et al. (Tue,) studied this question.