دانلود The Effect of Surface Roughness on Discharge Coefficient and Cavitations of Ogee Spillways Using Physical Models

Abstract

Background: Flow spillway structure is of major issues in dam construction and type of spillway design, considering appropriate discharge coefficient and long term investigation of spillway plot hydraulic performance are highly important.

Objective: Suitable graphs selection and supply based on type of wall roughness in different parts of peak spillways are keys to use this type of spillways in dam construction projects. To do this, using physical-hydraulic model, supreme complex of Khuzestan Water and Power Industry  performed measurement tests and observed hydraulic parameters and analyzed discharge coefficient in different fields including surface roughness in Ogee spillway model.

Results: Number of performed tests of the model with six types of surface roughness and  5 different flow rates totally include 30 tests.

Conclusion: Finally, increase of relative roughness of spillway discharge coefficient decreases in appropriate with surface roughness.  Also in results of the experiments show in different discharges, increasing the roughness decreases the cavitations index.