The threat of a chemical and/or biological weapon release in an urban environment is ever more increasingly becoming a concern. Witness the events that have transpired since September 11, 2001. Accurate and detailed contaminant transport modeling is essential for the management and prevention of, and training for this potential threat. CFD models coupled with atmospheric or urban boundary layer models provide by far the highest resolution and accuracy. However, in order to gain a level of confidence in these CFD models, validation against known experimental and/or actual measured data is required.

The purpose of this paper is to present a review of suitable experimental and field studies that can be used for urban CFD code validation and to show some sample validation cases using the Navy's contaminant transport model for urban environments, FAST3D-CT. Several studies have been identified and categorized based on study type (experimental vs. field), study results (flowfield vs. tracer) and geometric complexity. Three of these studies were selected for the present validation efforts, specifically a cube array, a rectangular box array, and a model urban intersection. The first study, the cube array, was accomplished in a water flume, whereas the latter two were performed in wind tunnels. All include both flowfield and tracer measurements. Models of these test cases were developed and simulations performed using FAST3D-CT with informative results.