Exponent has strong capabilities and deep experience in using Computational Fluid Dynamics (CFD) models to solve a range of atmospheric flow problems. CFD models use numerical techniques to solve the equations that govern the conservation of mass, momentum and energy. These models predict the microscale flow of fluids around or through complex structures and can include chemical reactions and multi-phase physics such as the droplets from flashing liquids. The CFD models used at Exponent include FLUENT®, OpenFOAM® and STAR-CD®.
Exponent staff have applied CFD to:
- Calculate the wind forces on buildings during a hurricane
- Model the accidental two-phase release of pressurized ammonia and chlorine
- Design wind screens to mitigate the transport of fugitive emissions or dust from material piles
- Model the dispersion of hydrogen sulfide released from a pipe at a refinery
- Model the fogging and recirculation of exhaust from mechanical draft cooling towers
- Model the wake effect of buildings on turbulence and wind speed at the area swept out by the rotor blades of wind turbines
- Stimate the plume rise from an air cooled condenser
- Model the potential contamination of fresh air intakes by rooftop vent emissions
- Model the plume rise and downwind ground level temperatures and carbon dioxide concentrations for a large flare
- Predict flammable vapor cloud dispersion from an LNG spill into an impoundment, and
- Model fog generation and dispersion caused by ambient air vaporizers.
Other applications for CFD may include dispersion within industrial complexes or city-centers, pedestrian-level wind studies, odor mitigation analyses, or indoor issues such as laboratory hood design. The development of a realistic atmospheric boundary layer and wind field in an environment with natural and man-made obstacles is a common theme in most of our work.
Exponent's CFD Project Experience includes:
- Wind-Induced Pressure Forces
- Design of Wind Fences
- Building Wake Effects on Wind Turbines
- Accidental Releases of Dense Gases
- Cooling Towers
Exponent Staff Publications Related to Atmospheric Applications of CFD
Schulman LL,DesAutels CG, Viti V. CFD simulations to predict wind induced damage to a steel building during Hurricane Katrina. 5th International Symposium on Computational Wind Engineering, Chapel Hill, NC, May 2010.
DesAutels CG, Schulman LL. Evaluation of the Desert Tortoise ammonia field tests with the FLUENT CFD model using unsteady RANS. 5th International Symposium on Computational Wind Engineering, Chapel Hill, NC, May 2010.
Schulman LL, DesAutels CG, Viti V. Application of computational fluid dynamics to air quality modeling. Guideline on Air Quality Models: Next Generation of Models Conference, Air & Waste Management Association, Raleigh, NC, October 2009.
Valerio, V., DesAutels C, Schulman L. Computational model of the flowfield around the Museum of Science. Boston Museum of Science Wind Energy Meeting, Boston, MA, May 2009.
Schulman LL, DesAutels CG. Estimating the effect of building wakes on wind power generation using the CFD model FLUENT. EUEC Energy and Environment Conference, Phoenix, AZ, February 2009.
Schulman LL, DesAutels CG. CFD simulation of building downwash in the EPA wind tunnel. Air & Waste Management Association 101st Annual Meeting, Portland, OR, June 2008.
Gavelli F, Bullister E, Kytömaa H. Applications of CFD (FLUENT) to LNG spills into geometrically complex environments. Proceedings, 2006 Mary Kay O’Connor Process Safety Center International Symposium, pp. 468-485, 2006.
de Foy B, Schulman LL. Near-field concentration predictions of a rooftop vent in an urban environment using CFD. Air & Waste Management Association 94th Annual Meeting, Orlando, FL, June 2001.
de Foy B, Schulman LL. Comparison of CFD simulations of building downwash with wind-tunnel observations. Air & Waste Management Association 93rd Annual Meeting, Salt Lake City, UT, June 2000.