Hydraulic Model Vortex Study Grand Coulee Third Powerplant,

摘要

Hydraulic model studies of the Grand Coulee Third Powerplant forebay indicated detailed vortex studies should be made. Vortex modeling is difficult because of lack of similitude between model and prototype. A literature search disclosed an Equal Velocity Method of vortex modeling and this method was used in this study. Without model trashracks,air-entraining vortices readily formed,and with model trashracks vortex action was reduced. Rafts,either floating or submerged,suppressed vortex formation. Investigations were made to determine the prototype area in the forebay that may be susceptible to vortex action and need raft protection. The report has 35figures and gives a detailed description of the investigation.