FEM3C, An improved three-dimensional heavy-gas dispersion model: User`s manual

Technical Report · Tue Mar 01 00:00:00 EST 1994

DOI:https://doi.org/10.2172/10163871· OSTI ID:10163871

Chan, S T

FEM3C is another upgraded version of FEM3 (a three-dimensional Finite Element Model), which was developed primarily for simulating the atmospheric dispersion of heavier-than-air gas (or heavy gas) releases, based on solving the fully three-dimensional, time-dependent conservation equations of mass, momentum, energy, and species of an inert gas or a pollutant in the form of vapor/droplets. A generalized anelastic approximation, together with the ideal gas law for the density of the gas/air mixture, is invoked to preclude sound waves and allow large density variations in both space and time. Thee numerical algorithm utilizes a modified Galerkin finite element method to discretize spatially the time-dependent conservation equations of mass, momentum, energy, and species. A consistent pressure Poisson equation is formed and solved separately from the time-dependent equations, which are sequentially solved and integrated in time via a modified forward Euler method. The model can handle instantaneous source, finite-duration, and continuous releases. Also, it is capable of treating terrain and obstructions. Besides a K-theory model using similarity functions, an advanced turbulence model based on solving the k - {var_epsilon} transport equations is available as well. Imbedded in the code are also options for solving the Boussinesq equations. In this report, an overview of the model is given, user`s guides for using the model are provided, and example problems are presented to illustrate the usage of the model.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: Department of Defense, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 10163871
• Report Number(s): UCRL-MA-116567; ON: DE94014731
• Resource Relation: Other Information: PBD: Mar 1994
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ENVIRONMENTAL TRANSPORT
F CODES
POLLUTANTS
FINITE ELEMENT METHOD
CONSERVATION LAWS
FLUID MECHANICS
MASS TRANSFER
BOUNDARY CONDITIONS
MESH GENERATION
EARTH ATMOSPHERE
540110
540120
990200
BASIC STUDIES
CHEMICALS MONITORING AND TRANSPORT
MATHEMATICS AND COMPUTERS