Dispersion from courtyards and other enclosed spaces.

The paper describes small scale wind tunnel experiments on the dispersion of contaminants discharged from the bottom of courtyards and other enclosed spaces. The experiments covered a range of courtyards with ratios of depth to width from 5- (consistent with light wells and other very deep cavities) down to 0.1 (consistent with shallow enclosed squares and piazzas that are frequently found in the urban environment).