A model for water vapour density in the unsaturated porous media.

The water vapour density is given by

\[
\rho_v = h\, \rho_{vS},
\]

where \(h\) is the relative humidity according to

\[
h=\exp({\frac{p}{\rho_w R T}}),
\]

with \(R\) the specific gas constant for water vapour, and \(\rho_{vS}\), is the saturated vapour density given by

\[
\rho_{vS}=10^{-3}\, \exp({19.819-4975.9/T}).
\]

The specific gas constant for water vapour \(R=461.6\,\text{J}\,\text{kg}^{-1}\text{K}^{-1}\), the value is calculated by \(R_g/M_w\) with \(R_g= 8.3144621\,\text{J}\,\text{mol}^{-1}\text{K}^{-1}\), the ideal gas constant, and \(M_w=0.018016\,\text{kg}\,\text{mol}^{-1}\), the molar mass of water.

The formula of this density model is presented on page 20 of [21].

In the application, the vapour density related terms in the mass balance equation are multiplied with \(1-S\) with \( S \), the water saturation. Therefore the application of the water vapour density model is naturally restricted in the unsaturated zones.

It belongs to **vapour_density**. That means the name of this property is **vapour_density**. Besides, it has no parameter to be input.

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Child parameters, attributes and cases

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Additional info

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From MaterialLib/MPL/Properties/Density/CreateWaterVapourDensity.cpp line 31

- This is a required parameter.
- Expanded tag path: NONEXISTENT.property.WaterVapourDensity
- Go to source code: → ogs/ogs/master

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Used in the following test data files

Used in no end-to-end test cases.