Research Projects

PhD Student: Yi-Ju Chou

We have developed a large eddy simulation code along with a moving mesh method and sediment transport model to study formation and evolution of sand ripples in waves and currents. Using a consistent second-order moving mesh scheme and a wall model, this numerical tool enables three-dimensional simulations of flow over the dynamic complex bottom topography. With the high grid resolution to resolve fine-scale turbulence features, this model is able to simulate turbulence-induced bedform initiation and transient processes of sand ripple evolution in both waves (Figure 1) and currents. Furthermore, sediment transport, flow features and turbulence structures (Figure 2) can be observed over transient bedforms. Unlike traditional CFD studies on flow dynamics over ripples and dunes, which employ high resolution CFD codes with the fixed synthetic bedforms, the present numerical model can be a power tool to study transient behavior of the flow and bedform in the subaqueous environment. Currently, the code is being used to study turbulence mixing, sediment transport and sand ripple evolution in combined wave-current flows.

This project is funded by the ONR Coastal Geosciences Program.

For more information please visit Yi-Ju's research web page.

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