Author(s): Shinji Fujii; Ichiro Kimura; Yasuyuki Shimizu
Linked Author(s): Yasuyuki Shimizu, Ichiro Kimura
Keywords: Density function method; 3D-CFD model; Pool-and-weir-type fishway; Fishmotion; Non-linear k-ε model
Abstract: This paper presents a three dimensional (3D) numerical model which can predict flow structures as well as fish movements in a pool-and-weir type fishway. In order to capture a large deformation of the free surface oscillation, we applied the density function method. As a turbulence model, the non-linear k-ε URANS (Unsteady RANS) model proposed by Kimura and Hosoda (2003) was adopted, which can efficiently predict complicated turbulence structure with separation and reattachment requiring much less CPU time than LES. The fish behaviour in rivers are simplified and incorporated into our numerical model considering previous biological studies. Grouping effects of fish motions was also considered in our model. In order to evaluate the model applicability, the model proposed herein was applied to the simulation of a real pool-and-weir-type fishway in the Tokachi River, Japan and the results are compared with observational data. The numerical results indicated that the present computational model could capture the turbulent flow structures as well as fish behaviours satisfactory. It is therefore shown that the present numerical fishway model is efficient tool for designing ecologically efficient fishway.