[case] VapourDiffusionPMQ

The Penman-Millington-Quirk (PMQ) Vapour diffusion model.

The vapour diffusion can be described by [28], [29],

\[ D_v=D_0 \left(\frac{T}{273.15}\right)^{n} D_{vr}, \]

where \(D_{0}\) is the base diffusion coefficient with default value \(2.16\cdot 10^{-5}\) \({\text m}^2 \text{Pa}/(\text{s}\text{K}^{n})\), \(n\) is the exponent with default value 1.8, \(D_{vr}\) is the the relative diffusion coefficient, and \(T\) is the temperature.

The Penman–Millington–Quirk (PMQ) model [28] is given as

\[ D_{vr}=0.66 \phi \left(\frac{\kappa}{\phi}\right)^{\frac{12-m}{3}}, \]

where \(\phi\) is the total porosity, \(\kappa\) is the air filled porosity, and \(m\) is a fitting parameter. The air filled porosity is defined as \( \kappa = \phi-\theta = \phi -S_L \phi \) with \(\theta\) the liquid content, and \(S_L\) the liquid saturation.

According to the study presented in [28], \(m=6\) is the best fitting parameter for the sieved, repacked soils that the authors tested. Therefore, \(m=6\) is used in the implementation, which gives

\[ D_{vr}=0.66 \phi (1 - S_L )^2. \]

Note: In order to maintain consistency with the implementation of the computations of other vapor-related parameters, \( \phi (1 - S_L )\) is removed from the implementation for this class and is multiplied back in the local assembler.

Child parameters, attributes and cases

Additional info

From MaterialLib/MPL/Properties/VapourDiffusion/CreateVapourDiffusionPMQ.cpp line 39

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

Used in the following test data files

Used in no end-to-end test cases.