مهندسی منابع آب (Jun 2016)
Application of the Standard Torbulance Model and the Volume of Fluid Method in Prediction of the Water Surface Profiles in a Hydraulic Jumps on the Triangular Corrugated Beds
Abstract
The hydraulic jump is one of the most important topics In the field of open channel flow, which has been extensively investigated. When a flow condition changes from a supercritical to a subcritical regime, the result is an abrupt rise in the water surface level accompanied by turbulent rollers. This phenomenon is called a hydraulic jump.Many researches have shown that the corrugated beds caused the conjugate depth and length of the hydraulic jump are reduced as compared to those of smooth beds. In this study, a 2D numerical simulation of hydraulic jump on a triangular corrugated bed was simulated using various turbulence models (Standard and RNG k – model and (SST) model) and Fluent software. Also, the free surface was determined, using the VOF method. Hydraulic jump was simulated in a rectangular channel with a triangular corrugated bed, using various Froude numbers within a range of 3-7.5. The numerical results showed that the turbulence model and the VOF method were suitable for predicting the free surface profiles of hydraulic jumps on triangular corrugated beds. The relative error of the predicted free surface profiles and measured value were within a range of 3%- 7%. Also, the results confirmed that on everage, the tailwater depth on triangular corrugated beds was 34.8% less than that of smooth beds under similar hydraulic conditions. The numerical model indicated that as the distance from jump’s toe is increased, the turbulent kinematic energy (K) is reduce; Moreover the maximum value of bed shear stress was obtained on jump’s toe.
