New Functionality in Version 4
- The physics interface for Heat Transfer in Porous Media now accounts for multiple immobile solids and fluids. There are two choices for averaging the thermal conductivity: volume average and a power law formulation.
- The physics interface for Heat Transfer in Porous Media also incorporates options for describing geothermal heating and thermal dispersion.
- The previous three separate formulations of Darcy’s law (pressure, pressure head, and hydraulic head) are available in one framework in version 4.0a. This makes it possible to mix boundary and initial conditions using any of these formulations. The Porous Media and Subsurface Flow physics interfaces are also able to specify isotropic, orthotropic or anisotropic permeabilities or hydraulic conductivities.
- The physics interface for Poroelasticity includes a poroelastic material model to account for isotropic poroelastic materials. The material properties can be written in terms of bulk and shear modulus, Young’s modulus and Poisson ratio, Lamé constants, or pressure and shear velocities. Orthotropic and fully anisotropic materials can be modeled if used together to the SME module.
- A new physics interface for Solute Transport incorporates the old application modes for solute transport in saturated porous media and variable saturated porous media in one physics interface. You can also add and remove species freely in the Chemical Species Transport physics interfaces.
- A new physics interface for Fracture Flow enables the solution of Darcy’s Law in thin shells and fractures, without having to mesh along the thickness of a thin layer. This substantially improves performance for a given accuracy compared to previous versions.
- You can specify the unit of time in days and years in the time-dependent solver. This improves the usability for geotechnical processes compared to the use of seconds.
- Darcy’s Law can now handle variable densities.
- The possibility to include a Forchheimer Drag extension to the fluid flow resistance in porous media flow has been added.
- It is now possible to include a convective term in the Brinkman Equations. This means that porous media flow including higher fluid velocity can be studied. The inclusion of the term is controlled using the Neglect inertial term (Stokes-Brinkman) switch available in the Brinkman Equations and the Free and Porous Media physics interfaces.
- Stabilization has been included for the Brinkman equations. The stabilization provides increased robustness and less computational cost for a given accuracy compared to previous versions. It is also imperative when solving problems including the convective term.
Backward Compatibility vs. Version 3.5a
Special Basis Functions or Elements
None of the special basis functions or elements for the finite element formulation of flow problems featured in version 3.5a are available in version 4.0a. However, the new stabilization functionality in version 4.0a for fluid flow is identical to using the bubble elements in 3.5a.
Other special elements that were available in 3.5a will not be re-implemented in version 4. The reason for this is that the stabilized formulation in version 4.0a gives high accuracy to a relatively small computational cost compared to the special elements.