An Introduction to Environmental Fluid Mechanics EFM

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An Introduction toEnvironmental Fluid Mechanics
(EFM)
Mirmosadegh Jamali Department of Civil
Engineering Sharif University of Technology March
8, 2003
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What is EFM?

• The study of flow and transport in surface water,
  groundwater, and atmosphere.
• Environmental significance
• Heat and mass transfer
• Turbulence and mixing
• Stratification

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Stratification

• Most fluids are density stratified
• Variations in temperature, salinity, etc.
• Very small density differences
• Enhance horizontal motions
• Inhibit vertical mixing
• Have important environmental consequences

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Research in EFM

• MIT
• Stanford University
• University of California at Berkeley
• University of British Columbia

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Examples of topics in EFM

• Dispersion of contaminants in rivers, lakes,
  seas, groundwater, and atmosphere
• Dynamics of lakes and reservoirs
• Internal waves
• Selective withdrawal
• Two-layer hydraulics
• Wave interaction
• Hydrodynamic Stability
• Numerical, analytical, or laboratory modeling

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Mixing in rivers
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Mixing in atmosphere
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Mixing in reservoirs
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Wind-induced mixing
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Seasonal cycle
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Numerical Simulation
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Wave-induced mixing
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Mixing in coastal waters
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Ocean outfalls
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Mixing in tailings ponds
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Island Copper Empty
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Closure Plan
ARD

• Flooded pit as passive treatment system for ARD
• 1. dilution.
• 2. neutralization.
• 3. sulphide-metal precipitation by anaerobic
  sulphate reducing bacteria.

Local Precipitation
7 m
Brackish Water Cap
Buoyant ARD Plume
Anoxic Salt Water
215 m
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Island Copper Waterfall
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Island Copper Full
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Profiles in the Pit Lake
Upper Layer
Intermediate Layer
Depth (m)
Lower Layer
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Selective Withdrawal
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Selective-withdrawal system
Selective withdrawal system installed in 1995
Hungry Horse dam, built in 1952
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Internal Waves

• A major type of motion within a stratified body
• Play an important role in mixing and transport in
  reservoir
• Long characteristic time-scale

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Wave modes in a two-layer fluid
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Standing surface and internal waves

• Photos
• 1st external mode
• 1st internal mode
• 2nd external mode
• 2nd internal mode
• 3rd internal mode

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Interaction of Waves
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Two-layer Hydraulics
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Exprimental Simulation
Numerical Simulation
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Hamilton Harbour Side
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Hydrodynamic Stability
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Kelvin-Helmholtz Billows
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Conclusions

• Many environmental problems are fluid mechanics
  problems
• EFM is a fast-growing multidisciplinary field in
  fluid mechanics
• Many unexplored problems in EFM