Magnetic Flux Conservation
The Magnetic Flux Conservation node adds Equation 2-22 above (or a similar equation depending on the selected constitutive relation) for the magnetic potential and provides an interface for defining the constitutive relation and the relevant material properties (for example, the relative permeability). There are two types of Magnetic Flux Conservation available; Magnetic Flux Conservation in Solids and Magnetic Flux Conservation in Fluids. This distinction decides how materials behave and how material properties are interpreted when the mesh is deformed.
Magnetic Flux Conservation in Solids applies to materials whose properties change as functions of material strain, material orientation, and other variables evaluated in a material reference configuration (material frame).
Magnetic Flux Conservation in Fluids applies to materials whose properties are defined only as functions of the current local state at each point in the spatial frame, and for which no unique material reference configuration can be defined.
In COMSOL versions 6.2 and earlier, this Solids/Fluids distinction was controlled within the Magnetic Flux Conservation node by specifying Solid/Nonsolid in the Material type setting.
Constitutive Relation b-H
See the settings for Constitutive Relation B-H under Ampère’s Law, except for these differences:
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Magnetic losses and Effective B-H curve, being time-harmonic material models, are not available.
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Select B-H curve to use a curve that relates magnetic flux density B and the magnetic field H as |B| =f (|H|). To define |B|, select From material (the default) to use the value from the material or select User defined to specify a value or expression for the magnitude of the magnetic flux density in the field that appears.