Analysis Of Open Channel Flow Numerical Simulation

The bend river are widespread in nature, the Yellow River named nine curves eighteen turns, bend be considered to be one of the basic component unit of rivers,the bend river flow have some unique features relative to the straight channel flow, such as river surface exist slope with high concave bank and low convex bank; circulation characteristics happened because of the moment from the cross section, along the flow direction, circulation is clockwise. Research on the characteristics of bend flow has a great realistic guiding significance for sediment transport,river management, embankment protection, the shore water inlet.And with the expansion of the computer’s memory and the computing speed, flow characteristics research gradually become feasible and mature by using numerical simulation method with the help of computer.This paper using numerical simulation method to study the general law of bend flow, specific contents are as follows:(1) The bend flow theory and present research situation and development trend of numerical simulation at home and abroad were introduced(2) Creating positive and negative physical model with 90 ° corner and mesh with the aid of ANSYS/ICEM CFD software(3) Solved the numerical model with the aid of ANSYS/FLUENT software(4)Analyzed the flow characteristics of bend river from he horizontal surface slope,corner circulation, the longitudinal velocity, and process the result data with post-processing software TECPLOTAfter the analysis of the above content processing, this paper get the following conclusion:(1) The surface appear obvious horizontal gradient with concave bank is higher than the convex bank level of continuous curves of open channel flow by inertia force,and the channel inlet and outlet water also appears level fluctuations affected by the corners.(2) A low water of concave bank flow to high water level of the convex bank in a bend flow, underflow is just the opposite, which makes the concave bank sediment transport to the convex bank; if transition section between the two bending is too Short to eliminate the forward curve of circulation,after bend flow influenced by first bending residual circulation and may emerge second circulation under the condition of certain times.(3)Along the longitudinal flow velocity increased gradually from thelongitudinal;mainstream near the convex bank in inlet, the mainstream gradually move to the concave bank for a distance, the mainstream close to convex bank again in the second bend,and go to the center of channel after a period of distances for outlet; Longitudinal velocity of surface velocity is the largest, middle velocity is second, the under velocity is minimal.(4)The standard k- ε, RNG turbulent model and RSM turbulence model calculation results show that: the three models all can reflect the basic trend of the flow, but the standard K- e turbulence model ability for the capture of the free surface is poor and bigger than two turbulence models, it can not correctly reflect the changing value of the free surface of the bend, RNG turbulent model similar to the RSM turbulence model results, but the RSM turbulence model for a long time to compute.