Summary of CFD-Urban Results in Support of the Madison Square Garden and Urban Dispersion Program Field Tests

This paper describes the results from a series of Computational Fluid Dynamics (CFD) simulations that have been made in support of the Madison Square Garden 2005 (MSG05) and Urban Dispersion Program 2005 (UDP Midtown) field tests. In support of the MSG05 test, the transport and dispersion of a dilute tracer gas, released at five locations near Madison Square Garden, has been modeled using CFD-Urban. (CFD-Urban is a Computational Fluid Dynamics model that is specialized for performing urban area transport and dispersion calculations, and is described in a companion paper at this conference.) These calculations indicate the strong influence of large buildings near the release upon both the near source flow field as well as the near-field and far-field dispersion behavior. Detailed velocity, turbulence and dispersion fields are shown, which display very wide lateral mixing, induced by the deep street canyons, as well as street level flow energization and extensive vertical mixing caused by the 1 Penn Plaza and 2 Penn Plaza buildings. Results from calculations in support of the UDP Midtown experiment are also shown, where detailed velocity, turbulence and contaminant transport fields show similar behavior. Dependent upon the availability of data from both tests, comparisons of the predicted to measured dispersion fields will be made.

Acknowledgements The authors gratefully acknowledge the financial support for the MSG05 and UDP CFD calculations from the Defense Threat Reduction Agency (Mr. Rick Fry) and the US Army Dugway Proving Ground (Mr. Jim Bowers).