Field
The Field node () is an attribute node that handles settings for field variables. Each field variable has a separate Field node. This attribute is used together with the Dependent Variables node. The Field node name matches the name of the variable and its variable in the namespace (for example, Temperature (comp1.T)).
Figure 20-11: An example of a Field node, which takes the name of the variable, in this case Displacement field (Material).
General
The Field components section displays the variable names for the field’s components. Also, when extra internal variables are used, these are displayed here as Internal variables.
The Solve for this field check box and, if applicable, the Reconstruction list are available if the Dependent Variables Defined by study step setting is User defined.
The Solve for this field check box controls whether to solve for the field (variable) or not. If the variable is not solved for, its value is determined by the settings in the Values of Variables Not Solved For section of the parent Dependent Variables node.
If this field is part of a physics for which a Model Reduction node is computing a reduced model that include reduction, you can choose a Reduced Model node from the Reconstruction list, if you want this field to use another reconstruction than the rest of the study.
Use the Store in output check box to control whether to store the variable in any output solution or not. A variable can still be solved for despite not being stored in output and vice versa. You can make the MPH file size smaller by not storing the field variable’s solution data if it is not of interest for the postprocessing (you may have some data in discrete points or probes that is sufficient, which you can provide as single degrees of freedom using algebraic equations). If the Dependent Variables node is user defined, and you have selected the Store in output check box, you can choose what to store in the output using the Store in output list:
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Choose All (the default) to store all solutions for the field in the output.
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Choose Selection to use one or more selection nodes to define what part of the field to store in the output; for example, to only store the field on a boundary of interest, thereby reducing the required memory. Click the Add button () to open an Add dialog box that contains all available selections. Select the selections that you want to add and then click OK. You can also delete selections from the list using the Delete button () and move them using the Move Up () and Move Down () buttons.
Scaling
Select a Method to control the scaling of a variable.
Unless From parent is selected, specifying a Method for a variable here overrides the Method selected in the Scaling section of the corresponding Dependent Variables operation node.
Select:
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Automatic to get an automatically determined scaling.
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From parent to use the scaling type selected in the Method list in the Scaling section of the corresponding Dependent Variables operation node.
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Initial value based to get a scaling that is determined from the initial values. Use this if the components of the initial values give a good estimate of the order of magnitude of the solution.
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Manual to manually enter a scaling, then enter a value in the Scale field.
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None to get no scaling.
Residual Scaling
From the Method list choose From parent (the default), Automatic, or Manual. For time-dependent problems, the Automatic residual scale is updated when a sufficiently large change in the residual is detected during time stepping. You can then enter a value in the Threshold for updating residual scale field, so that the residual scale updates automatically when a sufficiently large change in the residual is detected. The default value is 100. For Manual, enter a scale factor in the Scale field (default: 1). For the scaling, see Termination Criterion for the Fully Coupled and Segregated Attribute Nodes. A manual tuning of the scale factor may help convergence in some cases where the solution does not converge when using automatic scaling does not work (this could be the case for some contact problems, for example).