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ESTS0198 FEM-3.

FEM-3, Heavy Gas Dispersion Incompressible Flow

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1. NAME OR DESIGNATION OF PROGRAM:  FEM-3.
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2. COMPUTERS
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Program name Package id Status Status date
FEM-3 ESTS0198/01 Arrived 09-JAN-2005

Machines used:

Package ID Orig. computer Test computer
ESTS0198/01 VAX under VMS
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3. DESCRIPTION OF PROGRAM OR FUNCTION

FEM3 is a numerical model developed primarily to simulate heavy gas dispersion in the atmosphere, such as the gravitational spread and vapor dispersion that result from an accidental spill of liquified natural gas (LNG).
FEM3 solves both two- and three-dimensional problems and, in addition to the anelastic formulation, has options for using either the Boussinesq approximation or an isothermal assumption, when appropriate.
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4. METHOD OF SOLUTION

The model is based on solving the time-dependent, multidimensional conservation equations of mass, momentum, energy, and species. A generalized anelastic approximation is employed to accommodate large density changes and yet preclude sound waves (i.e., the fluid is considered to be basically incompressible but to have variable density). A modified Galerkin finite element method with eight-node isoparametric hexahedron elements (four-node quadrilaterals in two dimensions) is used for spatial discretization, and an improved forward Euler method is employed for time integration. The discretized Poisson equation for  pressure is solved by a skyline solver.
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5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM:
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6. TYPICAL RUNNING TIME

The sample problems required 1.5 and 19.5 CPU hours on a DEC VAX11/780
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7. UNUSUAL FEATURES OF THE PROGRAM:
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8. RELATED AND AUXILIARY PROGRAMS:
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9. STATUS
Package ID Status date Status
ESTS0198/01 09-JAN-2005 Masterfiled Arrived
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10. REFERENCES

- P.M. Gresho, S.T. Chan, C.D. Upson and R.L. Lee,
  A Modified Finite Element Method for Solving the Time-Dependent,
  Incompressible Navier-Stokes Equations,
  UCRL-88937, March 1983.
ESTS0198/01, included references:
- Stevens T. Chan:
FEM3 - A Finite Element Model for the Simulation of Heavy Gas Dispersion and
Incompressible Flow - User's Manual,
UCRL-53397, February 1983.
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11. MACHINE REQUIREMENTS:
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12. PROGRAMMING LANGUAGE(S) USED
Package ID Computer language
ESTS0198/01 FORTRAN-77
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13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  VMS
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14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

The FEM3 model is composed of three parts: a preprocessor PREFEM3, the main code FEM3, and two postprocessors TESSERA and THPLOTX. PREFEM3  and FEM3 use a limited number of LLNL computing environment system subroutines, which are not included. These are identified in the program and presumably can be replaced easily with equivalent subroutines suited to the local computing environment. Descriptions  of the 'missing' subroutines are included in the reference report. The postprocessors, used for plotting velocity vectors, contours, time histories, etc., depend heavily on LLNL graphics solftware which is not exportable; they are not included.
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15. NAME AND ESTABLISHMENT OF AUTHORS

          Stevens T. Chan
          Lawrence Livermore National Laboratory
          Livermore, California 94550
          USA
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16. MATERIAL AVAILABLE
ESTS0198/01
AAAREADME.TXT    Author's Readme file
PREMAIN.FOR      Source file
PREFIS.FOR       Source file
FIS.FOR          Source file
MTRX2D.FOR       Source file
FEM2OR3M.FOR     Source file
FEM2OR3.FOR      Source file
MAKECP2D.FOR     Source file
MAKECP3D.FOR     Source file
RHSAD2V.FOR      Source file
RHSAD3V.FOR      Source file
SMP2V.FOR        Source file
SMP3V.FOR        Source file
LLNL.FOR         Source file
POLYREAD.FOR     Source file
COM.COM          Instructions for compilation
FEMBACK.COM      FEM files backup procedure
FEMSTORE.COM     FEM files copying procedure
FEM3IN.LDC       Lid-Driven Cavity problem
FEM3OT.LDC       Lid-Driven Cavity problem
FEMCIN.LDC       Lid-Driven Cavity problem
INITCO.LDC       Lid-Driven Cavity problem
LOG.LDC          Lid-Driven Cavity problem
PREPIN.LDC       Lid-Driven Cavity problem
PREPOT.LDC       Lid-Driven Cavity problem
RMSERR.LDC       Lid-Driven Cavity problem
FEM3IN.UME       Burro 9, Liquid Natural Gaz Spill problem
FEM3OT.UME       Burro 9, Liquid Natural Gaz Spill problem
FEMCIN.UME       Burro 9, Liquid Natural Gaz Spill problem
INITCO.UME       Burro 9, Liquid Natural Gaz Spill problem
LOG.UME          Burro 9, Liquid Natural Gaz Spill problem
PREPIN.UME       Burro 9, Liquid Natural Gaz Spill problem
PREPOT.UME       Burro 9, Liquid Natural Gaz Spill problem
RMSERR.UME       Burro 9, Liquid Natural Gaz Spill problem
TAPE.FRO         Auxiliary file
TAPE.TO          Auxiliary file
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17. CATEGORIES
  • H. Heat Transfer and Fluid Flow
  • R. Environmental and Earth Sciences

Keywords: Navier-Stokes equation, dispersions, finite element method, fluids, fuel gas, gas spill, gaseous diffusion, hydrodynamics, incompressible flow, liquified natural gas, three-dimensional, two-dimensional.