Model Study for the Design of Emergency Stoplogs Deployed in a ComplexFlow Field — Part 2: Numerical Results

An emergency closure system using stoplogs was designed to stop the flow through a fish passage when the primary gates are not functional. Physical and numerical hydraulic models were conducted to develop the stoplog design for the Wanapum Future Unit Fish Bypass. Different design alternatives were evaluated to minimize the maximum cable tension during deployment and the hydraulic uplift force that could prevent closure. The hydraulic force on the stoplog and lifting beam were calculated using the commercial code Fluent. The Volume of Fluid (VOF) method was used to simulate the free surface. Structured and unstructured hybrid grids were used to simulate the complex geometry near the stoplogs. The predicted flow field for the stoplogs at different elevations are presented and discussed. Two-dimensional numerical results are compared against experimental data taken on the 1:24 scale laboratory model and used to understand the physics underlying the behavior of each geometric design.