ParSWMS

Three-dimensional applications often require a large number of finite elements to discretize realistically large transport domains. Even with the fast personal computers currently available, it is virtually impossible to solve within a reasonable computational time problems having more than about half a million nodes or more. To decrease the required computational time, Hardelauf et al. (2007) parallelized SWMS_3D to develop ParSWMS that distributes problems with a large number of elements over multiple processors working in parallel. SWMS_3D (Šimůnek et al., 1995) is the simplified predecessor of the 1.0 version of HYDRUS (2D/3D). While SWMS_3D simulates water flow and solute transport in three-dimensional domains, it does not consider some of the advanced features of HYDRUS, such as dual-porosity systems, hysteresis, and nonlinear and nonequilbrium solute transport. The ParSWMS code was developed for the LINUX or UNIX workstations using the installed free-wares MPI, PETSc and PARMETIS. Hardelauf et al. (2007) demonstrated that doubling the number of processors may decrease the computational time by up to nearly 50%.

An extended version of HYDRUS GUI supports fully ParSWMS. It allows users to create the three-dimensional flow and transport project in HYDRUS GUI and then save it using the format of ParSWMS input files. These input files can then be taken to a parallelized platform (a supercomputer or a cluster of PCs), on which ParSWMS can be run. Created output files can then be copied back to a PC with HYDRUS GUI, which will convert ParSWMS-created output files into the HYDRUS format. The results can then be analysed in HYDRUS GUI using all its graphical tools and comfort.

Šimůnek, J., K. Huang, and M. Th. van Genuchten, The SWMS_3D code for simulating water flow and solute transport in three-dimensional variably saturated media, Version 1.0, Research Report No. 139, U.S. Salinity Laboratory, USDA, ARS, Riverside, California, 155 pp, 1995.

Hardelauf, H., M. Javaux, M. Herbst, S. Gottschalk, R. Kasteel, J. Vanderborght, and H. Vereecken, PARSWMS: a parallelized model for simulating 3-D water flow and solute transport in variably saturated soils, Vadose Zone Journal, 6(2), 255-259, 2007.