THREE-DIMENSIONAL FLOW EFFECTS TO SIMULATE FLOWS IN A STRONGLY CURVED CHANNEL WITH PARTLY EMERGENT RIGID VEGETATION

The effects of three-dimensional flow in strongly curve channel with partly emergent vegetation were analyzed numerically by comparing the flow structure of the Bottom Velocity Calculation (BVC) method and conventional two-dimensional calculation (2DC) methods. Numerical calculations result show that BVC method is able to reproduce the flow structure investigated by the experimental dataset, decelerating the surface velocity and accelerating bottom velocity. The presence of vegetation on the inner bank reduces the strength of the secondary flow, while the outer bank vegetation increases the strength of the secondary flow. The secondary flow reduces the streamwise velocity in the non-vegetation region and moves the maximum velocity toward the outer bank. These results show the importance of considering the 3D flow effect for simulating partly vegetation in meandering rivers.