Abstract: In order to solve the problems of river erosion at concave bank and of sediment deposition at convex bank in actual bend rivers, the 3D hydraulic characteristics of bend channel with spur-dikes must be studied. The gas-liquid two-phase large eddy model was used to numerically simulate the hydraulic characteristics of flow in a 90° bend channel with a spur-dike. Comparisons of the simulated longitudinal velocity with the experimental data show a good agreement, which indicates that the large eddy model is an effective way to study the hydraulic characteristics of bend channels. The analysis of the distribution of velocity and flow fields on different horizontal plans, and on cross-sections of different bending angles, shows that the intensity of circulation near the concave bank is larger than that near the convex bank as a result of the secondary flow, and also shows that the spur-dike can effectively eliminate the circulation in the bend channel, and that the T-shaped groin has more advantages of improving the flow patterns of bend channels and of its own security.

Key words: bend flow, spur dike, transverse circulation, large eddy model