FEMLAB 3.1 - EARTH SCIENCE MODULE CHEAT SHEET - 8 December 2004
General description of the Earth Science Module
The Earth Science Module is a FEMLAB environment for modeling physical processes that
operate at the earth’s surface and in the subsurface. The interfaces and models employ
formulations and language that researchers in the field need and understand. Most of the
application modes underpin multiple physics couplings used to answer questions about
subsurface water supplies (aquifers), subsurface oil reserves (petroleum reservoirs),
landfills, environmental contamination, nuclear waste disposal, agriculture and irrigation,
seepage through dams, streams and estuaries, to name a few.
The model library contains model files and step-by-step instructions for examples from famous
experts, classic papers, other software manuals. Most of the models demonstrate concepts
useful in many applications. For example, the water flow and solute transport models
demonstrate tools that scientists and engineers will need to think about the flow of oil, heat
transport, and magma migration. Likewise bringing up the unusual example of electromagnetics
and fluid flow in the volcano model demonstrates the no-ceiling-on-your-ideas power of
FEMLAB at a glance, and it also demonstrates protocols that can be applied when modeling the
electromagnetic sensors to assess petroleum reservoirs and aquifers, for example.
Benefits of the Earth Science Module
Users unfamiliar with FEMLAB will never have seen:
o Easy to use equation templates or application modes to model variably saturated flow
(Richards’), saturated flow (Darcy, Brinkman), free flow (Navier-Stokes), solute
transport, and heat transfer in a single package;
o A package flexible enough that they can modify equations, create their own PDEs, and
link physics arbitrarily and get an automatic finite element code;
o Just-type-it-in expressions for material properties, postprocessing, and more;
o Access to application modes in FEMLAB that will allow them to think about nonstandard
physics couplings, such as linking between flow, temperature, structural deformation or
linking between surface and porous media flow.
Folks already using FEMLAB will need to know:
o The module combines variably saturated flow, saturated flow, free flow, solute transport,
and heat transfer in a single package;
o Variably saturated flow with Richards’ equation has never been seen in FEMLAB before.
o The application modes automatically account for multiphysics that comes from having
either or both solids and fluids in one volume (dispersion of chemicals and heat,
chemicals that attach or sorb to soils)
o Tools to keep track of properties of the fluids, solids, and gases in the porous
media.
What do you get?
 EQUATIONS: Seven easy-to-use application modes set up just for earth
sciences:
1. Richards’ equation (pressure, pressure head, or hydraulic head) – slow
flow in variably saturated porous media, where the pore space is not
completely filled. For example, irrigation of dry soil, water disappearing
into the sand at a beach; seeking a physics-based position for the water
table.
Leigh Soutter, leigh.soutter@comsol.com, phone: 781.273.3322, cell: 650.776.3910
FEMLAB 3.1 - EARTH SCIENCE MODULE CHEAT SHEET - 8 December 2004
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2. Darcy’s law (pressure, pressure head, or hydraulic head) – flow in
porous media. One Darcy’s law for systems saturated with a single
liquid. As in an aquifer or oil reservoir. Multiple Darcy’s law equations
for two- and three-phase flow. As in a water injection to mobilize oil
toward an extraction well, simultaneous flow of oil and gas.
3. Brinkman equations (pressure and velocity) – flow in porous media
that is fast enough that shear is important. For example, fast flow
near the perforation of a well;
4. Navier Stokes equations (pressure and velocity) – free flow outside of
porous media, in channels for example. Includes options for density
driven (“non-isothermal”) and “swirl” flows. For example, flow in
wells, rivers, fractures.
5. Solute transport (concentration) – transport of one or more chemical
species in fluid, solid, or fluid-solid systems. Support for defining
velocity dependent dispersion and sorption. For example, pollution, gas
transfer, microbial activity.
6,7. Heat transfer (temperature) – transport of heat in systems with
immobile constituents (conduction) with or without moving fluids
(convection and conduction). Supports defining effective properties for
media with fluids, solids, and gases; velocity dependent dispersion; and
geotherm generated by radiogenic decay.
Seamless access to FEMLAB and its Modules for multiphysics couplings.
If they want to, they can link to MATLAB and run FEMLAB from the MATLAB
command line instead of using the FEMLAB graphical user interface; set up FEMLAB
models from the MATLAB command line and import them into the FEMLAB GUI; use
MATLAB routines and commands inside the FEMLAB model; use MATLAB analysis
tools inside FEMLAB during postprocessing; export FEMLAB results to MATLAB and
simulink, and so on.
MODELS: 22 models with physics couplings that cover many types of
investigations:
Pore scale flow – Navier-Stokes flow in the interstices of a microscale
porous medium, geometry from scanning electron microscope image
(example from important research group)
Variably saturated flow and transport examples
o Interpolation – flow with material properties from experimental data
(example from Hydrus and SWMS manuals)
o Variably saturated flow – flow example from Arizona hydro group
o Sorbing solute – chemical attaches to solids as it moves (Hydrus and
SWMS )
o Reaction chain – variably saturated flow and transport of parentdaughter-granddaughter decay chain involves volatilization (Hydrus and
SWMS manuals)
Aquifers and petroleum reservoirs
o Examples that match important analytic solutions (Theis, Hantush and
Jacob, Cooper and Papadopolus), including a wellbore storage model
that accounts for how the fluid in the well influences withdrawals from
the reservoir
o Oil flow to a perforated well from petroleum engineers at Heriot-Watt
Univ
Leigh Soutter, leigh.soutter@comsol.com, phone: 781.273.3322, cell: 650.776.3910
FEMLAB 3.1 - EARTH SCIENCE MODULE CHEAT SHEET - 8 December 2004
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Flow that transitions from subsurface to free flow shown for
petroleum flow to a well, also applies to groundwater-surface water, and
fracture flow
o Two-phase flow – compares results from flow simulations for air-water,
air-oil, and oil-water systems (duplicates USEPA study)
Flow and deformation
o Biot poroelasticity - deformation of reservoir when fluids are pumped
out (USGS study)
o Freezing soil describes deformation related to volume change of icewater phase change (Netherlands transportation study)
Chemical transport, pollution, remediation
o Variably saturated flow and transport examples (from Hydrus and
SWMS see above)
o Solute injection – point source fluid injection with chemicals migrates
through aquifer (example from MT3D manual)
Electromagnetics - volcano shows water flow coupled to electromagnetics
– a multipart example involving 3D geometry generated with real
topographic data (published study)
Leigh Soutter, leigh.soutter@comsol.com, phone: 781.273.3322, cell: 650.776.3910