Application of a 3-D CFD model to investigate flood-related engineering problems

The paper discusses the application of a fully 3-D, non-hydrostatic, RANS model with deformable free-surface capabilities to several main types of flood-related engineering problems. The model is found to accurately simulate the dam break flow developing in a 900 open channel bend for which detailed validation data from a laboratory experiment are available. First practical application deals with mitigation of flooding extent via implementation of flood protection structures such as floodwalls. Numerical results show that the floodwalls effectively protect the critical regions situated in the vicinity of the river and the reduction of the flooded area with respect to the case when floodwalls are not present is about the same at high-flow conditions and at low-flow conditions. The second application deals with prediction of flow structure around a location containing a bridge whose deck becomes submerged as the flood wave passes the bridge location. The final application considers the effects of a sudden dam break failure for a dam situated upstream of the Iowa City, USA.