Numerical Simulations of Efficiency of Curb-Opening Inlets

The geometry of highway pavement and drainage inlets, especially cross slope, longitudinal slope, and local depression and transition length, usually determine the highway surface drainage capacity. In this study, a three-dimensional computational fluid dynamics (CFD) software, FLOW-3D, is used to develop models simulating unsteady, free-surface, shallow flow through curb-opening inlets, thereby demonstrating that an advanced CFD model can be used as a virtual laboratory to evaluate performance (i.e., inlet efficiency) of curb-opening inlets with different geometry conditions. Predicted intercepted flow and inlet efficiency agree well with laboratory measurements. Flow simulations were extended to smaller cross slopes for which laboratory tests were not conducted but which can occur in a highway transition.