VALIDATION OF A HYBRID 3-DIMENSIONAL AND 2-DIMENSIONAL NUMERICAL FLOW MODELING TECHNIQUE FOR AN INSTANTANEOUS DAM-BREAK

摘要

While physical models remain the mainstay of the water and environmental industry, numerical simulations using Computational Fluid Dynamics (CFD) are increasingly common and provide a comparatively inexpensive and rapid way to study catastrophic conditions and validate designs. However, available computational resources have often restricted the use of CFD to certain classes of problems, such as the modeling of spillways and intakes. A novel addition to the commercial CFD package FLOW-3D bypasses this restriction by solving the full 3-D Navier-Stokes equations in parts of the computational domain and solving the simpler 2-D depth-averaged flow equations in other parts of the computational domain. This unique approach reduces the computational overhead required for many simulations and consequently allows the simulation of previously intractable configurations, such as 3-D dam breaks and the subsequent downstream flooding. To validate the hybrid approach, FLOW-3D was used to replicate an experimental study of an instantaneous dam break. The resulting mean relative error in the numerical solution is less than 6% when compared to the physical experiment.