HST3D 2.0 is a finite-difference, modelling program for the simulation of fluid, single-species solute and heat transport in three dimensions under saturated conditions. HST3D allows you to include solute adsorbtion and decay in your model. The flow, heat, and solute transport equations are coupled; advective transport is linked to fluid velocity; fluid viscosity depends on temperature and solute concentration and fluid density depends on pressure, temperature, and solute concentration. Boundary conditions include specified pressures, specified temperatures, specified mass fractions, specified flux, specified heat flux, specified solute flux, leakage boundaries, river leakage boundaries, evapotranspiration, aquifer-influence boundaries, heat conduction, and wells. Free surface (water table) conditions are allowed although not with a tilted coordinate system. Although, you can simulate fluid, solute, and heat transport simultaneously, you not required to simulate solute and/or heat transport if your problem does not require it. All boundary conditions may vary with time. Internally, the calculations are perfomed in metric units but the data may be entered as either metric or US customary units. Solute concentrations in HST3D can be entered as either mass fraction or a scaled mass fractions that ranges from 0 to 1. Initial pressures can be either a specified hydrostatic condition, a specified water table configuration or specified pressures.
Typical applications of HST3D include the study of waste injection into fresh and saline aquifers, contaminant plume movement, sea-water intrusion in coastal regions, brine disposal, freshwater storage in saline aquifers, heat storage in aquifers, liquid-phase geothermal systems, and similar transport situations.
Two related programs come with HST3D 2.0. BCFLOW is a post-processing program for determining flux within specified regions. DIMEN is used to determine the array sizes required in HST3D to run a particular model. The output of DIMEN can be used to recompile HST3D to a size capable of running the model.
The HST3D GUI provides a convenient way to set up the input files for HST3D and the related program BCFLOW. Instead of preparing a long file of numbers in a precise format, you can set up your model graphically on the screen. In the illustration below, for example, the permeability of an aquifer has been interpolated from a number of know locations (not shown). For simplicity, a second aquifer below the top one has been assigned a uniform permeability that happens to be much lower than the typical permeability of the upper aquifer. The topograpy of the surface between the two aquifers has been specified by a series of contour lines shown in color. An Argus ONE expression has been used to compare the elevations of individual elements within a layer to the elevation of the interface between the aquifers and to assign the permeability of individual elements the permeability of the appropriate aquifer. The boundary between the aquifers is between the orange and yellow contour lines. You can see a distinct change in the color of individual grid cells at the change between aquifers. The grid cell colors reflect their permeability.
It would be impractical to create a model of this complexity by hand but with the HST3D Graphical User Interface and Argus ONE, it can be set up easily. In addition, in Argus ONE, the data defining aquifer properties and boundary conditions are independent of the grid. Thus, you can destroy the grid and create a radically different one without needing to re-enter data. Instead of tediously creating the input file for HST3D, you can instead concentrate your time and effort on making your model better.
The HST3D GUI provides extensive on-line help in the form of a series of linked web pages. For nonspatial data, there are also flyby hints that appear when you position your mouse over an edit box or other control. These direct you to the place in the HST3D manual where the data for that control is described. The online help also gives a complete description of the spatial data and how it is related to HST3D variables.
The HST3D GUI includes:
If you wish to learn more about the capabilities of the HST3D GUI, read through the descriptions of the example models. These are in pdf format.
The HST3D GUI also includes descriptions of the example models and two examples.
The Shape file import PIE used in the second example model is available from the Argus ONE web site.