Isotropic linear material for moisture transport – IsoLinMoisture

Linear isotropic material model for moisture transport problems described by the linear diffusion equation. Note that the symbols \(k\) and \(c\) in (118) have a different meaning than in (117). The reason is that the nonlinear model for moisture transport described in Section Nonlinear isotropic material for moisture transport – NlIsoMoisture traditionally uses \(c\) for permeability and (118) should be obtained as a special case of (121). On the other hand, the heat conduction model from Section IsoLET was implemented earlier and the input parameters are directly called \(k\) and \(c\), so changing this notation now could lead to confusion for some older input files.

(118)\[k\frac{\partial h}{\partial t} = \nabla \cdot \left( c \nabla h \right)\]

where \(h\) is the pore relative humidity (dimensionless, between 0 and 1), \(k\) is the moisture capacity [kg/m³], and \(c\) is the moisture permeability [kg/m^cdots].

The model parameters are summarized in Table 61.

Table 61 Linear isotropic material for moisture transport - summary.

Description	Linear isotropic material for moisture transport
Record Format	IsoLinMoistureMat num (in) d (rn) perm (rn) capa (rn)
Parameters	num material model number d material density perm moisture permeability capa moisture capacity
Supported modes	_2dHeat
Tests/Examples	tm/isolinmoisture.in