A case study of a pool and weir fishway modeled with OpenFOAM and FLOW-3D

OpenFOAM's interFoam solver is validated for modeling the complex three dimensional flow field of a large pool and weir fishway. Numerical results from OpenFOAM and the commercial solver FLOW-3D are compared and validated with in situ experimental velocity, turbulence and water surface profiles. OpenFOAM and FLOW-3D produced similar flow fields. The models accurately predicted velocity magnitudes throughout the pool and the barrier velocity immediately downstream of the notch. The models over-predicted the width and depth of the jet issuing from the notch and significantly under-predicted turbulent kinetic energy levels within it. In both models a large roller occupies a generous volume of the sampled pool, the presence of which is not supported by experimental measurements. The findings demonstrate that interFoam coupled with the standard k − ϵ turbulence model is able to estimate barrier velocities, flow rates, turbulence magnitudes and depths to accuracies acceptable for fishway design evaluation.