Near-building turbulent intensities, fluxes, and vortices

A series of field studies were conducted to detect, identify and characterize turbulent and mean flow features and behavior that are generated by interacting with a single building. These field measurement activities were completed at the White Sands Missile Range, New Mexico during 2003 through 2005 by scientists and engineers of the US Army Research Laboratory, The sensor placement and over all design was constructed to locate and measure formation, intensity, and dissipation of flow features reported by wind tunnel, water channel, and field experimentalists. The development of new models and the improvement of existing micro-scale model/codes drive the need for better understanding of these processes and phenomena in both space and time.

The first field study utilized thermodynamic and wind sensors on 10m towers and one five meter roof mounted mast. Quantities were measured at the 2 and 10m levels AGL on the ground–based towers and 5m only on the roof mast. Our most recent field study incorporated aspects of the earlier studies and more. The same towers and locations were instrumented with three levels of sonic anemometers at 2.5, 5.0, and 10.0m. Three additional sonic anemometers were mounted on individual tripods at the 2.0m level. All sonics were sampled at 20HZ. The three new sonics were placed to detect the reattachment zone and the horizontal vortices that form downwind of the corner of the building. A variety of flow features were observed, identified, and documented. These flow features include : flow reversal as a vertical eddy in the cavity zone, lateral corner vortices, accelerated flow over the roof top, the reattachment zone, and downwind velocity deficits and enhancements.

Computations and analyses of turbulent fluxes and indices are in progress. Values of the wind and temperature fluxes, variances, TKE, and mean values of wind speed and direction, temperature, friction velocity, heat flux, and Z/L specifically are being calculated. The turbulence intensity index both upwind and downwind of the building is also computed.

* R. M. Cionco will present a podium paper preferably at a joint session.