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extended Richards' equation

extended Richards' equation More...

Description

This model implements a variant of the extended Richards' equation for quasi-twophase flow (see e.g. Vanderborght et al. 2017).

The extended Richards' equation

\[\frac{\partial (\phi S_w \varrho_w) }{\partial t} + \frac{\partial (\phi (1-S_w)\varrho_n X_n^w ) }{\partial t} - \nabla \cdot \left\lbrace \varrho_w \frac{k_{rw}}{\mu_w} \; \mathbf{K} \; \left( \nabla p_w - \varrho_w \textbf{g} \right) + {\bf D_{n, pm}^w} \varrho_n \nabla X^w_n \right\rbrace = q_w, \]

where:

  • \( \phi \) is the porosity of the porous medium,
  • \( S_w \) represents the saturation of the wetting-phase,
  • \( \varrho_w \) is the mass density of the wetting phase,
  • \( \varrho_n \) is the mass density of the non-wetting phase,
  • \( k_{rw} \) is the relative permeability of the wetting phase,
  • \( \mu_w \) is the dynamic viscosity of the wetting phase,
  • \( \mathbf{K} \) is the intrinsic permeability tensor,
  • \( p_w \) is the pressure of the wetting phase,
  • \( \mathbf{g} \) is the gravitational acceleration vector,
  • \( \bf D_{n,pm}^{w} \) is the effective diffusivity of water in the non-wetting phase,
  • \( X_n^w \) is the mass fraction of water in the non-wetting phase,
  • \( q_w \) is a source or sink term in the wetting phase,

additionally models water vapor diffusion in the gas phase. The model is derived based on the two-phase flow equations based on the assumption that the gas phase does not move but and remains at constant pressure.

Classes

struct  Dumux::ExtendedRichardsIndices
 Index names for the extended Richards model. More...
class  Dumux::ExtendedRichardsIOFields
 Adds I/O fields specific to the extended Richards model. More...
class  Dumux::ExtendedRichardsLocalResidual< TypeTag >
 Element-wise calculation of the Jacobian matrix for problems using the extended Richards fully implicit models. More...
struct  Dumux::ExtendedRichardsModelTraits
 Specifies a number properties of the extended Richards model. More...
class  Dumux::ExtendedRichardsVolumeVariables< Traits >
 Volume averaged quantities required by the extended Richards model. More...

Files

file  indices.hh
 Index names for the extended Richards model.
file  iofields.hh
 Adds I/O fields specific to the extended Richards model.
file  localresidual.hh
 Element-wise calculation of the Jacobian matrix for problems using the extended Richards fully implicit models.
file  model.hh
 This model implements a variant of the extended Richards' equation for quasi-twophase flow (see e.g. Vanderborght et al. 2017).
file  primaryvariableswitch.hh
 The primary variable switch for the extended Richards model.
file  volumevariables.hh
 Volume averaged quantities required by the extended Richards model.