Accession Number : ADA183547

Title :   Tracking Two-Dimensional Freezing Front Movement Using the Complex Variable Boundary Element Method.

Descriptive Note : Special rept.,

Corporate Author : WILLIAMSON AND SCHMID IRVINE CA

Personal Author(s) : Hromadka,Ted

PDF Url : ADA183547

Report Date : Jun 1987

Pagination or Media Count : 64

Abstract : The CVBEM is used to develop a computer model for estimating the location of the freezing front in soil-water phase change problems. The CVBFR1 computer program is based on the following major assumptions: 1) the problem is two-dimensional; 2) the entire soil system is homogeneous and isotropic; 3) the problem thermal boundary conditions are constant values of temperature (or stream function); 4) soil water flow effects are neglected (the problem is strictly geothermal); 5)all heat flow from the freezing front is within the control volume, there is no heat flux associated with the freezing front from exterior of the control volume; and 6) the freezing front movement is slow enough that heat flux along the moving boundary can be determined by assuming steady state heat flow conditions for small durations of time (i.e., timesteps). The CVBEM is used to model the thermal regime of the soil system. The theory and development of the CVBEM are given in CRREL internal report 969, by Hromadka. Because the numerical technique is a boundary integral approach, the control volume thermal regime is modeled with respect to the boundary values, and, therefore, the CVBFR1 data entry requirements are significantly less than those usually required of domain methods. Soil-water phase change along the freezing front is modeled as a simple balance between computed heat flux and evolution of soil-water volumetric latent heat of fusion. To model displacement of the freezing front, program CVBFR1 provides two options: displace the freezing front coordinates with respect to changes in the y-coordinate only, or with respect to a vector normal to the freezing front boundary.

Descriptors :   *HEAT TRANSFER, *COMPUTERIZED SIMULATION, *SOIL SCIENCE, *FREEZING, *THERMAL BOUNDARY LAYER, BOUNDARIES, CONTROL, VOLUME, HEAT FLUX, TEMPERATURE, CONTROL, THERMAL PROPERTIES, DISPLACEMENT, NUMERICAL METHODS AND PROCEDURES, COMPLEX VARIABLES, MOTION, SOILS, WATER FLOW, BALANCE, FUNCTIONS(MATHEMATICS)

Subject Categories : Cartography and Aerial Photography
      Thermodynamics

Distribution Statement : APPROVED FOR PUBLIC RELEASE