CCC-0477 FEWA-FEMA.

1. NAME OR DESIGNATION OF PROGRAM:  FEWA-FEMA.

3. DESCRIPTION OF PROGRAM OR FUNCTION

FEWA is a finite element model  designed to treat complex transient real-world problems of sources/  sinks, Dirichlet boundary values, Neumann or Gauchy fluxes, and leaky confining beds (aquitards) simultaneously.
FEMA deals with the construction, verification, and demonstration of a finite element model of material transport through aquifers. The particular features of FEMA are its versatility and flexibility  to deal with as many real-world problems as possible.

4. METHOD OF SOLUTION

In FEWA, both quadrilateral and triangular elements, or a combination of the two, are used to facilitate the discretization of a coumpound region with highly irregular curved boundaries. Also, a pointwise iteration solution strategy for solving the matrix equation approximating the partial differential equation is included as an alternative to the direct solution method. This inclusion makes the model efficient and applicable to large-field problems when the bandwidth of the matrix becomes large.  Three optional sorption models are embodied in FEMA. These are linear isotherm and Freundlich and Langmuir nonlinear isotherms. Point as well as distributed source/sinks are included to represent  artificial injection/withdrawals and natural infiltration of precipitation. All source/sinks can be transient or steady state. Finite element methods are adopted to transform the governing differential equations to the matrix equation. To increase the applicability of the model in terms of stability and convergence, twelve options have been included for the derivation of the matrix equation. The resulting matrix equation is solved with either the direct elimination or successive relaxation technique.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM:  None noted.

6. TYPICAL RUNNING TIME:  FEWA-FEMA runs in < 20 CPU sec.

Test case included in this package has been run at NEA-DB on an IBM 3090. Execution times were: 0.33 seconds (FEWA); 0.35 seconds (FEMA).

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES:

- G.T. Yeh and  D.D. Huff:
  FEWA: A Finite Element Model of Water Flow Through Aquifers.
  ORNL-5976  (November 1983)
- G.T. Yeh and  D.D. Huff:
  FEWA: A Finite Element Model of Material Transport Through
  Aquifers.
  ORNL-6063  (January 1985)

11. MACHINE REQUIREMENTS

FEWA-FEMA is operable on the IBM 3033 computers. Input/output is < 1000.
NESC9592/01: The two test cases included in this package ran at NEA-DB on a VAX 8810 computer in less than 8.5 seconds each.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED

FEWA-FEMA was written in FORTRAN H. The FEWA sample problem uses a 508K region and the FEMA sample problem uses 268K.
NESC9592/01: The test cases ran at NEA-DB on a VAX 8810 under VMS V5.0-1 (VAX 8810)

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS:

15. NAME AND ESTABLISHMENT OF AUTHORS

          Oak Ridge Laboratory
          Oak Ridge, Tennessee, U. S. A.

File name	File description	Records
CCC0477_01.001	INFORMATION FILE	92
CCC0477_01.002	FEWA INPUT GUIDE	1518
CCC0477_01.003	ORIGINAL JCL	12
CCC0477_01.004	JCL USED AT NEADB	113
CCC0477_01.005	FEWA SOURCE PROGRAM (FORTRAN IV)	3285
CCC0477_01.006	FEWA SAMPLE CASE INPUT	76
CCC0477_01.007	FEWA SAMPLE CASE OUTPUT	357
CCC0477_01.008	FEMA INPUT GUIDE	1870
CCC0477_01.009	FEMA ORIGINAL JCL	14
CCC0477_01.010	FEMA JCL USED AT NEADB	114
CCC0477_01.011	FEMA SOURCE PROGRAM (FORTRAN IV)	4233
CCC0477_01.012	FEMA SAMPLE PROBLEM INPUT	42
CCC0477_01.013	FEMA SAMPLE PROBLEM OUTPUT	369