Dam Break Flow: A Comparative Model Study Using OpenFOAM and BASEMENT

Dam break flows have been a focus of attention for a long in the hydraulic engineering discipline. The interest stems from their high hazard potential to human life and property. This research investigates a laboratory dam break flow using a 3D Reynolds-averaged Navier–Stokes (RANS) and a 2D shallow water Eq. (2D SWE) model. The two numerical models have been compared to measured data regarding flow depth, streamwise surface flow velocity, and point velocity. The results show that as far as a simulation of water depths at gauging stations is concerned, both models are almost at par with an error of about 20% of the mean depth value. Further, the comparison of surface velocity field reveals that though both models are capable of reproducing the salient flow features, e.g., oblique hydraulic jump, wake, etc., the 3D RANS model is more accurate in predicting the jump length and the so-called wet–dry fronts. The important contribution of this research lies in clearly enunciating the tradeoffs between a 2D SWE model and a 3D RANS model. The former model is computationally efficient and accurate as far as flow depth and velocity are concerned while the latter model provides a more complete result output, e.g., vertical flow velocity, turbulent kinetic energy and turbulent dissipation, etc. However, for obtaining significant accuracy with a 3D model a more accurate turbulence model than RANS is required which necessitate usage of very refined mesh (~ mm), thus, raising the cost of the simulation manifold.