Flow Simulation in Curved Open Channels Using FLUENT Model

• Main Authors: Li, Yen-Jei, 黎硯杰
• Other Authors: Yeh Keh-Chia
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/454twa

碩士 === 國立交通大學 === 土木工程系所 === 106 === The purpose of this study is to investigate the flow characteristics and the distribution of three-dimensional flow pattern in curved open channel. A threedimensional computational fluid dynamics software is adopted to simulate 3 experiment cases with different curvatures. The Reynolds number of the cases is about 100,000 and the ratio of radius of curvature ( Rc ) and width ( B ) of each case is 8.33, 1, 3. By simulation, one can select a better k-ε turbulent model to simulate flow in curved open channels. The preprocessing is made in ANSYS ICEM 14.0 in present study. The geometry is made in the Cartesian coordinate axis system. The mesh is composed of hexahedron structure grid. The total grid number is different in each case. ANSYS FLUENT 14.0 is adopted to simulate flow in curved open channels. Multiphase model–VOF and Open Channel Flow are used to deal with the interface of air and liquid. Water discharge is imposed on the upstream boundary and fixed water depth is imposed on the downstream boundary. Three k-ε turbulent models in FLUENT are adopted, RNG k-ε turbulent model as the test group and the others as the comparison group. Three experiments with different channel curvatures, Rc/B, are simulated to verify the applicability of each k-ε model. The postprocessing is made in Microsoft Excel. One can transform the coordinate system from Cartesian system to the coordinate usually used in river flow simulation – the longitudinal axis which is perpendicular to the cross section and the lateral axis which is in the cross section. Through the comparison between the experimental data and simulation results obtained from those different k-ε turbulent models, the results of velocity are examined and discussed in depth. Longitudinal velocity of three k-ε turbulent models has little different from others and all fit well with the experimental data, but lateral velocity does not. The results show that the simulation with RNG k-ε turbulent model is better than others.