| Groundwater, the major source of human drinking water, is susceptible to contamination from industrial and agricultural activities. This research develops a web-based simulation system of remote high performance computing model for contaminant transport and retention in soils. A three-dimensional advection-dispersion-reaction MRTM model, based on previous experimental and theoretical studies, is proposed to analyze the transport and retention of chemical contaminants in groundwater flowing through soils. Since three-dimensional experiments are difficult to implement and verify, this simulation system provides scientists an alternative to trace the contaminant movement in soils outside laboratories.; The alternating direction implicit (ADI) algorithm is used in this study to reduce the computational complexity. Although the ADI method is very efficient to solve the governing advection-dispersion-adsorption equations in the three-dimensional MRTM model, achieving higher order accuracy with different boundary conditions remains a difficult research topic. This research develops a new numerical scheme to achieve second-order accuracy with the Neumanntype boundary conditions. Furthermore, parallel computing is used to achieve high performance using powerful multiprocessor computers.; A web-based simulation system provides users a friendly interface for remote access to the system through Internet browsers, so as to utilize remote computing resources transparently and efficiently. In the client-side computing one-dimensional MRTM simulation system, the legacy code written in FORTRAN and C are wrapped and reused with Java code, which provides the web-based graphic user interface (GUI). The server-side computing three-dimensional MRTM simulation system integrates the remote high performance computing resources, database management systems, online visualization functionality, and web-based user-friendly GUIs. Given access to the Internet, users can execute and manage remote high performance computing jobs anywhere anytime, even through a web browser from a laptop personal computer.; In summary, this research has the following four contributions: (1) Extending the one-dimensional MRTM transport and retention model to three-dimensional applications. (2) Using the alternating direction implicit (ADI) numerical algorithm to reduce the computational complexity and achieving second-order accuracy with the Neumann-type boundary conditions. (3) Using parallel computing to achieve high performance on multiprocessor parallel computers. (4) Integrating the web-based system with user-friendly interfaces, which provide client-side and server-side computing services and web-based visualization functionality. |
