Army Turbulence Model Predicts Dispersion of CBRN Threats in Atmosphere

Some portions of cities, such as Chicago shown here, consist of complicated building structure. This Army turbulence model will be used to simulate/replicate CBRN dispersion in a field whose structure is similar to that of Chicago. (U.S. Army)

Breakthrough research from Army scientists in the fundamentals of atmospheric turbulence modeling provides a prototype model for the dispersion of the chemical, biological, radiological and nuclear (CBRN) threats in the atmosphere.

The unique turbulence model has broad applications to both civilian and military activities to include the prediction and control of air contamination, during both day and night, the first of its kind to ever do so.

Dr. Xiping Zeng, researcher with the U.S. Army Combat Capabilities Development Command’s Army Research Laboratory, described the importance of such a model in protecting against a CBRN attack. “Their defense is usually implemented via CBRN passive protection, contamination avoidance and CBRN mitigation. All of these defense actions rely on an accurate turbulence model for the dispersion of CBRN materials in the atmosphere. An accurate turbulence model can provide direction for a defense action, just as GPS provides direction for a car driving.”

Turbulence is the oldest unsolved problem in classical physics, Zeng said. It is more complicated in the atmosphere than in the laboratory, as atmospheric stability and other meteorological factors are involved. Hence, the turbulence in the atmosphere is usually treated as the hardest problem in the atmospheric sciences.

According to Zeng, the Army and other government agencies need an operational software package to respond to CBRN attacks; however, a perfect software package depends on two factors, a high-performance computing, or HPC, facility and an accurate turbulence model on CBRN dispersion.

Since powerful HPC facilities are now available in the Department of Defense, this new turbulence model provides the last “brick” to build a perfect software package.

“Current turbulence models are quite primitive and are based on concepts developed decades ago,” Zeng said. “In contrast, this proposed model is constructed based on the new, much more accurate concepts of the atmospheric turbulence and its processes.”

The model properly represents two processes, thermals and gravity waves. As a result, it works well during both daytime and nighttime, the first of its kind to ever do so.

The model’s results are being compared with observational data, showing the model works well even while the atmospheric stability and meteorological factors vary greatly.

Since turbulence is commonly observed around us, he said, the developed turbulence model has broad applications to both civilian and military activities.

The model, for example, can be used to improve the prediction of weather and climate change; help the design of buildings/bridges in civil engineering by computing the force of wind on buildings/bridges; improve the prediction and control of air pollution, as turbulence determines the dispersion of pollutants; and help plan the flight of aircraft and unmanned aerial vehicles, as turbulence can create severe hazards for these vehicles.

“For the Army, when a CBRN attack occurs, there is little information for the Soldier to react,” Zeng said. “This computer model can retrieve more information on the attack for the Soldier using the limited information available.”

Once an attack occurs, the CBRN-dispersion model receives the information from the battlefield and then determines the location of the CBRN source. Finally, the information on the location is sent to the Soldier to remove the CBRN source as well as the optimum locations to avoid the hazard.

Zeng’s next step in the research is to extend the model’s capability into more complex environments, such as battlefields in dense urban areas or under forest canopies, helping ensure its practical application in the future.

Article courtesy of U.S. Army, edited for context and format by CBRNE Central.

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