Geosyntec's CFD experts apply efficient modeling techniques to provide quality solutions to our clients' complex fluid problems, including transient and multiphase.
Our aim is to generate results that are readily understandable to our clients and directly address their particular concerns. Our practitioners use commercial CFD codes, such as ANSYS-CFX and FLUENT, and open source software, such as OpenFOAM. We currently hold multiple solver licenses for ANSYS-CFX. For blast analysis we use FLACS and our own modeling tool, the 'Computational Explosion and Blast Assessment Model' (CEBAM).
CFD Services to the Oil and Gas Industry
Geosyntec uses CFD modeling to support the quantification of major hazards:
- Jet and pool fires
- Smoke dispersion, including ingress into HVAC ducts and temporary refuges
- Blast analysis and gas detection
- Ventilation efficiency for accidental releases in enclosed environments
- Thermal loading on safety-critical structural elements
- Dispersion of toxic gases
We have developed and published a number of innovative techniques that have assisted our clients in these areas, including pre- and post-processing analysis of the data generated by the CFD solver.
CFD Modeling of Explosions and Fires
At Geosyntec, we use a variety of CFD tools to model severe events including explosions and fires. CFD simulations can accurately represent key physical processes, such as how a jet release of flammable gas interacts with obstacles. This is key in setting the flammable mass involved in an explosion and is not as accurately assessed using hand calculations.
Using CFD modeling for analyzing explosion and fires also allows for a better characterization of the pressure and thermal loading of structures and equipment. It provides detailed time histories of critical aspects, such as blast loading and visual obstruction due to smoke.
Because the CFD based modeling tools include an accurate representation of the geometry, mitigation strategies such as grating and blast walls can be evaluated. Aspects of the event, such as wind speed and direction, which can affect dispersion of gas, heat, and smoke, are accurately represented. Other outputs, including smoke patterns, are also useful for risk and safety studies.
CFD Modeling of Bombing Events
Geosyntec has a proven track record of providing CFD analysis to address the possibility of malicious attacks using high explosives. Both public and private organizations need to understand the vulnerability of their communities to such events, as the consequences can be better understood, and adequate response planning can be put in place.
CFD modeling of potential events aids in the design of structures by providing accurate resolution of blast loadings. Since CFD-type modeling uses a 3D representation of the design, key elements such as how pressure waves reflect off walls and neighboring structures are more clearly understood. Scenarios such as internal explosions, which are not easily analyzed using simple methods, can be accurately represented.
Using CFD modeling also allows for the evaluation of protective systems, such as new vehicle designs. Blast loading is highly dependent on the geometric configuration of the systems involved, therefore, an accurate analysis depends on the capabilities of the CFD modeling used. Geosyntec use their own modeling tool, CEBAM, which was developed in-house by CFD experts. CEBAM ensures that the most accurate results available are delivered to clients.
CFD Services to Water and Wastewater
CFD is a key tool for process optimization and design within the water and wastewater treatment industry. Many of the standard design tools used in plant design use gross simplifying assumptions, whereas CFD allows a realistic, 3D view of the actual flows with minimal underlying assumptions. Geosyntec is an industry leader in applying CFD for water and wastewater treatment, including:
- Modeling of sludge settlement, including hindered settling
- Flow distribution and loading
- Aeration processes
- Assessment of mixing and short circuiting in the biological phases of treatment
- Disinfection processes, including chlorine decay, fluid age studies, and UV dosing
In many cases, the CFD modeling we have carried out has led to improvements to existing processes, resulting in peak flow rate increases of 20% or more with no detrimental effect on effluent quality. This has been achieved at a fraction of the capital cost of installing new equipment.
CFD Modeling of Tanks and Clarifiers
Geosyntec has developed a CFD modeling software solution tailored to provide quick and easy assessments of clarifier and tank performance. 'ClariSim' is a CFD tool for clarifiers, including advanced models for sludge settlement. It has been well-validated through major experimental studies, and has been deployed on over 50 sites. 'TankSim' is a similar tool for modeling three-dimensional flows in tanks, including flows generated by horizontal or vertical axis impellers. In nearly all tank studies, fluid-age and residence time distribution (RTD) analyses are undertaken in order to characterize mixing and identify problematic short-circuits.
The underlying models in both ClariSim and TankSim can be readily applied in non-standard clarifiers and tanks. Unusual geometries or mixing regimes can be processed using the standard CFD solvers, and additional physical models can be included, such as buoyancy effects due to heat exchange and decay and mixing of chemical constituents. In all cases, care is taken to communicate results to our clients in a manner that is readily understandable, and that directly addresses the problems at hand.
CFD Modeling of Environmental Flows
Environmental flows can be modeled using CFD for a variety of applications. At Geosyntec, we have modeled river and lake flows extensively in support of environmental permitting, including modeling of thermal plumes from cooling water discharges, toxicity studies, and hydraulic zone of influence studies for intake structures. We have developed many fast and robust techniques for the interpretation of bathymetry data to create accurate 3D models of lakes and rivers, and are highly experienced in creating high-resolution structured meshes on which to perform numerical analysis.
We have also analyzed wind patterns and turbulence levels around buildings, structures and helipads, and have a solid understanding of the issues of turbulence and transient flows generated by blunt bodies. We seek to validate our CFD modeling wherever possible by comparison with the latest published data, and adhere to best-practice guidelines where appropriate.