# Destaques do COMSOL Multiphysics® Versão 5.3A

For users of the Subsurface Flow Module, COMSOL Multiphysics® version 5.3a includes new Kozeny-Carman and Cubic Law permeability models, as well as four new tutorial models. Browse these Subsurface Flow Module updates in more detail below.

### Kozeny-Carman Permeability Model

The Kozeny-Carman permeability model, available for the Darcy's Law interface in COMSOL Multiphysics® version 5.3a, allows you to estimate the permeability of granular media from the porosity and particle diameter.

### Cubic Law Permeability Model for Fracture Flow

The so-called cubic law for the fracture transmissivity is now available for the Fracture Flow interface. This model computes the permeability from user-defined values for the fracture's aperture (fracture thickness) and roughness factor.

### Thin Barrier Feature in the Two-Phase Darcy’s Law Interface

The Two-Phase Darcy’s Law interface can now be used to define permeable walls on interior boundaries. These interior boundaries are used to represent thin, low-permeability structures. The Thin Barrier feature avoids expensive meshing of thin structures, such as geotextiles or perforated plates. Additionally, the permeability of the interior wall can be either isotropic or anisotropic.

### Revamped Free and Porous Media Flow Interface

With the new version of the Free and Porous Media Flow interface, you can couple laminar or turbulent free flow with porous media flow. This interface remains unique in its coupling with the electrochemistry interfaces for the modeling of porous electrodes.

### New Tutorial Model: Permeability Estimation

This tutorial model demonstrates the capability of the COMSOL Multiphysics® software for estimating the permeability of a porous material by creating a detailed fluid flow model in a small unit cell. The computed permeability can be used in homogenized models using Darcy's law or the Brinkman equations.

Flux in a unit cell representative of a porous medium consisting of spherical particles. The calculations from the unit cell are used to compute effective transport properties for the homogenized porous domain.

Flux in a unit cell representative of a porous medium consisting of spherical particles. The calculations from the unit cell are used to compute effective transport properties for the homogenized porous domain.

Application Library path:
Subsurface_Flow_Module/Fluid_Flow/permeability_estimation

### New Tutorial Model: Geothermal Doublet

This tutorial model demonstrates how to use COMSOL Multiphysics® to model geothermal doublets. A geothermal doublet is used to produce hot groundwater, extract heat, and reinject the cooled water into the subsurface. The extracted heat can be used for domestic heating, or converted into electric energy. The tutorial model is described in more detail on the COMSOL Blog.

The background surface plot shows the z-coordinate (right legend), the fracture surface shows the temperature (left legend), and streamlines show Darcy's velocity field (no legend) in the geothermal doublet.

The background surface plot shows the z-coordinate (right legend), the fracture surface shows the temperature (left legend), and streamlines show Darcy's velocity field (no legend) in the geothermal doublet.

Application Library path:
Subsurface_Flow_Module/Heat_Transfer/geothermal_doublet

### New Tutorial Model: Solute Injection

This tutorial model demonstrates the application of COMSOL Multiphysics® to a benchmark case of subsurface flow and solute transport. The model tracks a contaminant that enters an aquifer at a point, such as an injection well or toxic spill, and spreads through the aquifer over time. The model results are then compared to the analytic solution.

Concentration field (in ppm) of a contaminant around the injection point in an aquifer with a net advective flow, from left to right in the plot. The plume of contaminant is the result of advection and dispersion in the porous domain.

Concentration field (in ppm) of a contaminant around the injection point in an aquifer with a net advective flow, from left to right in the plot. The plume of contaminant is the result of advection and dispersion in the porous domain.

Application Library path:
Subsurface_Flow_Module/Solute_Transport/solute_injection

### New Tutorial Model: Solute Transport

This tutorial model demonstrates the application of COMSOL Multiphysics® to a benchmark case of subsurface flow and transient solute transport. The simulation tracks the solute transport in groundwater flow accounting for longitudinal and transversal dispersivities. The model covers an area of 16 km2 over 1000 days, and the results are compared to analytical solutions in a benchmark.

Solute concentration (color table) obtained from a benchmark model for groundwater flow. The gray streamlines show the flow direction, starting in the far corner and ending in the corner closest to the view plane.

Solute concentration (color table) obtained from a benchmark model for groundwater flow. The gray streamlines show the flow direction, starting in the far corner and ending in the corner closest to the view plane.

Application Library path:
Subsurface_Flow_Module/Solute_Transport/solute_transport