Subdomain Boundary Period-Budget Panel

This panel provides the possibility to accurately calculate fluid, mass and heat flows across model-internal subdomain boundaries. The subdomain boundary can be the entire outer boundary of an element selection, or an arbitrary part of it. Compared to the Subdomain Boundary Rate-Budget panel, here the flow rates are integrated over a specified time period.

The results are shown when the Active check box is checked and FEFLOW is in simulator mode. Separate tabs are shown for fluid flow, mass (possibly different species), and heat flow according to the Problem Class settings.

Domain of Interest (DOI)

Use Selection as Boundary-Budget Domain in the context menu of a stored element selection in the Selections panel can to be chosen to make a stored element selection available as Domain of Interest (DOI).

 

Symbol	Description
	Alternatively, the stored element selection that is currently selected in the Selections panel can be added to the list of available selections by hitting this button.
	Remove one of the available selections with this button.

 

The rate budget values shown refer to the selection chosen in the drop-down list. If no stored selections have been added in addition, the entire domain as well as the current node and element selections are available.

Masking Domain (MD)

A second element selection can be used to restrict the flow calculation to a subset of the boundaries of the Domain of Interest (DOI). This is the Masking Domain (MD). The boundary-flow calculation can be either limited to only the edges/faces defined by the Domain of Interest (DOI) that also belong to MD (are edges/faces of elements in the MD) or that do not belong to MD (are not edges/faces of elements in the MD).

 

Symbol	Description
	Apply the element selection that is currently selected in the Selections panel as masking domain.
	Remove masking element selection.

The boundary-flow calculation is internally done on a nodal basis. In case of calculating flows for adjacent subdomain boundaries (using masking domains), the nodal flows at the interface of both boundaries will be included in both subdomain budgets. Thus the sum of subboundary flows balanced separately for a DOI will be somewhat larger than the flow obtained for the entire DOI. The finer the spatial discretization is, the smaller the difference.

Flow Through DOI Boundary

The subdomain boundary flows are divided into negative flows (out of the DOI - red) and positive flows (into the DOI - green) and are shown in bars for the different kinds of flow:

 

Budget Component	Description
BCs	Flow through BCs that are fully on the DOI boundary, i.e., not shared with any parts of the model domain adjacent to the DOI
Internal Transfer	Flow through parts of the DOI boundary that are inside the model domain, including any BCs shared with parts of the model domain adjacent to the DOI
Total Loss & Gain	Total loss and gain from BC-related and internal transfer flow
Net	Net loss or gain

The subdomain boundary-rate budget only accounts for model-internal flows and boundary conditions on the DOI boundary. Use the Rate-Budget panel instead if you need a complete budget for a subdomain, including storage effects, sources/sinks and BC-related flows.

Period

Here, the time period for the cumulative budget is to be defined. Having a full results file (*.dac) loaded, the time period can be chosen as an arbitrary interval within the saved time period. Otherwise (during the simulation run) the temporal integration starts at simulation start and runs until the current time step.

When having loaded a full results (*.dac) file, the ∫...dt button has to be hit to start the budget calculation. Optionally, rate and period budget can be exported to a *.txt file during the calculation by choosing a file name after starting the calculation. Hitting the button starts the calculation and export for all quantities that have Export checked in the Period Budget and Subdomain Boundary Period Budget panels. For each exported quantity, a separate file name has to be chosen.

 

For use during the simulation run, the calculation should be activated before the simulation is started to integrate subdomain boundary flows occurring from the simulation start to the current time step.

Budget Export

The calculated period-budget values can be exported to a text file (*.txt) via the context menu on the panel (Export Current Values...) after the budget has been calculated.

When having loaded a full results (*.dac) file optionally, rate and period budget can be exported to a *.txt file during the calculation by choosing a file name after starting the calculation by hitting the ∫...dt button.

The format used to display the numbers in the bars can be changed by using the Number Format entry in the context menu of the panel.