Fluxes across Mesh Lines
This command displays a dialog window that shows actual and cumulative, water and (convective) solute fluxes across selected mesh-lines. Mesh-lines, across which the fluxes are calculated are selected in the Mesh-Line dialog window.
Data displayed in the graph can be exported into an ASCII file using the Export command. Using the Export All command one can export into an ASCII file all fluxes (actual and cumulative water and solute fluxes) for a particular mesh line.
Information for this graph is read from the CrossSect.out file that contains data organized into the following columns:
Time |
Time |
Flux(i) |
Water flux across the ith cross-section |
CumFlux(i) |
Cumulative water flux across the ith cross-section |
SolFlux(i) |
Solute flux across the i-th cross-section (note that only convective solute flux (i.e., dispersive-diffusive flux due to concentration gradient is neglected) is evaluated) |
CumSFlx(i) |
Cumulative solute flux across the i-th cross-section (note that only convective solute flux is evaluated) |
The following units are used to express fluxes in this graph:
Water Flux |
[L2/T] or [L3/T] for 2D and three-dimensional axisymetrical problems, respectively. |
Cumulative Water Flux |
[L2] or [L3] for 2D and three-dimensional axisymetrical problems, respectively. |
Solute Flux |
[M/L3*L2/T = M/L/T] or [M/L3*L3/T = M/T] for 2D and three-dimensional axisymetrical problems, respectively. |
Cumulative Solute Flux |
[M/L3*L2 = M/L] or [M/L3*L3 = M] for 2D and three-dimensional axisymetrical problems, respectively. |
Water Fluxes across internal lines (mesh-lines) are calculated in HYDRUS similarly as fluxes through the boundary nodes with prescribed Dirichlet boundary conditions (see the Technical Manual). Nodal fluxes are calculated from the finite element matrix equation that is obtained by discretization of the Richards equation and assembled for all elements on one side of the selected internal line. The finite element matrix equation for internal fluxes is calculated at the last iteration after convergence for given time level had been achieved. Fluxes calculated directly from the Richards equation are much more accurate than fluxes calculated using Darcy’s law and have the same accuracy as the overall solution.
Convective Solute Fluxes are then calculated simply by multiplying water flux values with nodal concentrations. None that the reported solute fluxes across mesh-lines do not include dispersive/diffusive solute flux.
See the X-Y Graph topic for more information on this graph.
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