A Comparative Study of Air-Water Flow in Hydraulic Jump using OpenFoam and ANSYS Fluent Softwares

Document Type : Research Paper

Authors

1 Department of civil engineering, faculty of engineering, Urmia university, Urmia, Iran

2 Department of civil engineering, faculty of engineering, Urmia university,Urmia,Iran

10.22059/jwim.2025.388864.1206

Abstract

Abstract



A hydraulic jump is a type of rapidly varied flow that occurs when supercritical flow transitions to subcritical flow over a short distance. This phenomenon has gathered significant attention from researchers due to its numerous advantages. In this study, the air-water two-phase flow field of the hydraulic jump is simulated in two dimensions using two software packages: OpenFoam and ANSYS Fluent. The Froude number for the hydraulic jump is 7.5, and the Reynolds number is 1.4 x 10^6. In order to simulate the flow field, the volume of fluid (VOF) method, along with Reynolds-Averaged Navier-Stokes (RANS) equations, were employed. The results from the two software packages were compared with one another, as well as with existing laboratory results and findings from the literature. The results include various hydraulic characteristics of the jump, such as roller length, secondary conjugate depth, free surface profile, maximum forward and backward velocity along the channel and the air concentration of the flow. These findings indicate an appropriate agreement between numerical simulations and experimental data. The calculated length of the hydraulic jump roller was 1.51 meters using OpenFoam and 1.55 meters using ANSYS Fluent, resulting in errors of approximately four and seven percent, respectively, compared to laboratory values. The coefficient of determination for the free surface profile was 99% for OpenFoam and 95% for ANSYS Fluent, while the Kling-Gupta Efficiency (KGE) index for the free surface profile was 0.94 and 0.8, respectively. The maximum air concentration in the shear region of the roller was observed at a depth of 1.42 times the initial depth of jump, with a concentration value of 0.41.

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