Large eddy simulation of flow and mass exchange in an embayment with or without vegetation

This paper presents a 3D large eddy simulation model to investigate the flow phenomena in an embayment with or without vegetation in a straight channel. This model takes into account the existence of vegetation by adding the vegetation drag force to the momentum equations. The equations of mass, momentum were implemented in σ-coordinate, and the operator splitting method is used based on finite difference schemes. A fluctuating velocity generated by synthetic eddy method is imposed at the inlet boundary. The model is first validated by two cases: flow in an embayment without vegetation in a straight channel, and flow in an open channel with submerged vegetation. The comparisons show a good agreement with the measurements. The model is then applied to simulate flow patterns and mass exchange in the embayment with vegetation and/or varying the embayment aspect ratios. Lastly, the model is applied to the field.