**RSICC CODE PACKAGE PSR-454**

**1. NAME AND TITLE**

SOLA-DF: Transient 2-Dimensional 2-Phase Flow.

**2. CONTRIBUTORS**

Los Alamos National Laboratory, Los Alamos, New Mexico through the Energy Science and Technology Software Center, Oak Ridge, Tennessee.

**3. CODING LANGUAGE AND COMPUTER**

FORTRAN IV; CDC7600 (P00454C760000).

**4. NATURE OF PROBLEM SOLVED**

SOLA-DF is a numerical solution algorithm for gas-liquid mixture dynamics in two space dimensions and time. The two-phase system is described by a set of mixture equations plus a relation describing the relative flow of one phase with respect to the other. The algorithm contains models to represent the interphase exchange rates of mass, momentum, and energy for water-steam mixtures.

**5. METHOD OF SOLUTION**

SOLA-DF uses a finite difference technique, which includes the Implicit Continuous-fluid Eulerian (ICE) method as an optional feature, to solve the drift-flux equations of two phase flow in two-dimensional plane or cylindrical coordinates. A wide variety of boundary conditions are possible, including free-slip, no-slip, specified inflow-outflow, continuative out-flow, periodic, and constant pressure boundaries. Implicit pressure gradients are used to eliminate the Courant condition as a stability requirement, making the code useful at all Mach numbers.

**6. RESTRICTIONS OR LIMITATIONS**

Simple equation of state, relative velocity model and phase transition model are assumed. When large phase transition rates are present, care must be exercised to make sure the solution is independent of the time-step.

**7. TYPICAL RUNNING TIME**

The grind time, or time to advance the solution in one cell by one time-step, is typically 0.5 to 1.0 ms on a CDC7600. NESC executed the sample problem in less than 8 CP minutes on a CDC7600.

**8. COMPUTER HARDWARE REQUIREMENTS**

124,000 (octal) words of memory are required for execution.

**9. COMPUTER SOFTWARE REQUIREMENTS**

SCOPE, LTSS and a FORTRAN IV compiler are required.

**10. REFERENCES**

C. W. Hirt, N. C. Romero, M. D. Torrey, and J. R. Travis, "SOLA-DF: A Solution Algorithm for Nonequilibrium Two-Phase Flow," NUREG/CR-0690, LA-7725-MS (June 1979).

NESC, "SOLA-DF, NESC No. 832.7600, Errata to LA-7725-MS Input Description," NESC Note 80-06 (July 9, 1979).

LASL Program Library Write-up (January 1979).

**11. CONTENTS OF CODE PACKAGE**

Included in the package are the referenced documents and one 3.5" DOS formatted diskette containing source code and example problem. No executables are included with the package.

**12. DATE OF ABSTRACT**

October 1999.

** KEYWORDS:** FLUID DYNAMICS