交錯排列高低砥墩於魚道設計之數值水理特性分析

本文使用計算流體力學軟體FLOW-3D模擬池堰式魚道於不同流量以及交錯放置不同砥墩之流場模擬探討，模擬加入紊流模型(k-ε two-equation model)計算，以及流體體積法(volume of fluid, VOF)法追蹤自由液面位置，求解其中連續方程式及Navier-Stokes Equation，並透過FLOW-3D輸出模擬數值，模擬類型為池堰式魚道，其設計為魚道入水口及出水口0.6m落差；魚道長度為6m長；1m寬；而設計三種砥墩排列: 砥墩同高、砥墩半高半低以及砥墩交錯之類型，並以流量Q(0.06、0.12cms)流入模型。而也使用FLOW-3D模擬(Fujita and Maruyama, 2002)階梯跌水流試驗與(Ead et al., 2004)變流量變坡度及變檔板高度之池堰式魚道試驗，以上二種案例之模擬流場與其試驗作比較也得到相近似之趨勢。透過設計池堰式魚道類型以及觀察其魚道水理特性、魚體上溯路徑以及流速適應性分析作為探討設計三種類型魚道，並歸納出本文Type3型，交錯排列高低砥墩為設計流量上最為適合魚體上溯之魚道。

關鍵字

池堰式魚道；自由液面；交錯高低排列

並列摘要

This study uses FLOW-3D (Computational Fluid Dynamics) software to simulate the hydrodynamics simulation of pool and weir fishways at different flow rates and the fishway design with height difference staggered arrangement. In the FLOW-3D simulation, add k-ε two-equation turbulence model to calculate, and volume of fluid (VOF) method to track the free surface, by solving the continuity equation and the Navier-Stokes Equations. The model is a pool and weir fishway, which is designed with a 0.6m drop between the inlet and outlet of the fishway; the length of the fishway is 6m long and 1m wide; There are three design types of pier arrangement: the same height; the piers are half-height; and half-low, where the piers are staggered, and the flow rate is Q (0.06, 0.12cms). The simulations were verified by the experiments of Fujita and Maruyama, 2002 step flow test and the test of Ead et al., 2004 with variable flow, variable slope and variable height of weir of pool and weir type fishway. The simulated flow field is also designed similar to these two experiment. Through the design of pool and weir fishway and observation of its water physical characteristics, fish uptrack path and flow rate adaptability analysis, it is concluded that Type3 in this paper, staggered arrangement of high and low piers is the most suitable fishway for fish uptracking in terms of design flow.