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Overview
• Many aspects of the Geosciences now use physically-based models for research
• Incorporating these into classes is often problematic
• Students could benefit from early exposure to these techniques
• New tools and faster computers offers an oppurtunity for educators
The Past
021
12
2
22
2
=∂∂
−∂∂
−+⎟⎟
⎠
⎞⎜⎜⎝
⎛
∂∂
+−∂∂
+∂∂
rp
rG
zu
ru
ru
rru
G rrrr αεν
021
12
2
22
2
=∂∂
−∂∂
−+⎟⎟
⎠
⎞⎜⎜⎝
⎛
∂∂
+∂∂
+∂∂
zp
zG
zu
ru
rru
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t
pS
tz
p
r
p
rr
pkr ∂
∂=
∂∂
−⎟⎟⎠
⎞⎜⎜⎝
⎛
∂∂
+∂∂
+∂∂
εεα
μ 2
22 1
( ) ⎟⎟⎠
⎞⎜⎜⎝
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+= β
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( )( )[ ]νννλ
+−=
121
E
The Present - Modeling Tools
• A number of GUI-based flexible modeling environments are available
• Real time simulation and visualization
• Useful for Lecture and Laboratory
• Two examples– COMSOL Multiphysics– Topodrive/particle flow
COMSOL Multiphysics
• A powerful generalized finite-element PDE solver with visualization
• Specific Earth Science Modules• Ideal for exploring coupled processes
– Fluid flow and deformation– Fluid flow and transport
• Good for setting up a problem and allowing students to perform sensitivity analysis
Topodrive/ParticleFlow
• 2D Steady state groundwater flow with particle transport– Developed by Paul Hsieh, USGS– Java-based, web app
• http://water.usgs.gov/nrp/gwsoftware/tdpf/tdpf.html
• Example use …
210 m
100 m
Normal stress on the system and the fractures.
Permeability of fractures under lithostatic stress conditions.
Hydraulic head where the permeability of fractures is constant.
Hydraulic head where the permeability of fractures is function of stress
Finite Element Model
A mesh is applied to the 2D model space
Plane Strain
Darcian Flow
Recharge
No Flow
Hydraulic Head
Gravitational Stress
Fixed Boundary
Fracture is an internal boundary
Displacement allowed
Permeable Fracture