Integrating Numerical and Physical Models for BMPs Loaded by Highway and Bridge Runoff.

The fate of particulate matter (PM) and associated pollutants in unit operations and processes (UOP) for highway drainage clarification are subjectto the size hetero-dispersivity of PM coupled with unsteady flow rates. This study applied multiphase computational fluid dynamics (CFD) validated with physical model results to simulate a screened hydrodynamic separator (HS) and a granular media radial cartridge filter (RCF). Coupled with controlled physical modeling examining UOP mechanisms, CFD predictions of PM fate are in good agreement with measured effluent concentrations, particle size distribution (PSD), as well as head loss for steady flow loadings forthe RCF and the HS. CFD modeling was successfully extended to model a real-time rainfall-runoff event with coupled transient hydrodynamics and particle transport. In the study post-processing results with physical model validation provided in-depth insight into the mechanistic behavior of the UOPs by means of three dimensional hydraulic profiles, particle trajectories, particle and flow velocity distributions, and radial and axial pressure distributions.