Modeling Ocean Currents in COMSOL

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Modeling Ocean Currents in COMSOL

• Reza Malek-Madani
• Kevin McIlhany
• U. S. Naval Academy
• 24 Oct, 2006
• rmm_at_usna.edu

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CCBOM

• Center for Chesapeake Bay Observation and
  Modeling
• Mathematics
• Oceanography
• Physics
• Ocean Engineering
• Chemistry

Acoustic Wave and Current Profiler (AWAC)
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Velocity Vector Field, Chesapeake Bay, Dec 27,
1999, Courtesy of Tom Gross, NOAA, Coastal
Survey Division http//chartmaker.ncd.noaa.gov/csd
l/op/images/UVanim.gif
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dx/dt u(x, y, z, t), dy/dt v(x, y, z, t)
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Bathymetry
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Deformation in MATLAB (N. Brasher, RMM, G.
Fowler)
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Particle Fate in MATLAB
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• How do the errors in the velocity field affect
  the errors in the dynamical systems computations
  and the particle fates?
• Are the statistics of the particle trajectories
  stable and realizable relative to the statistics
  of the velocity field?
• Are stable and unstable manifolds of the system
  dx/dt u, dy/dt v computable if u and v are
  known only locally in time (90 day date length)
  and in space (incomplete data collection)?
• New hydrodynamic model

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Goals and Strategy

• Goals
• Obtain velocity field for the dynamics of the
  Chesapeake Bay, based on real wind and planetary
  forcing, and
• Apply dynamical systems tools to the velocity
  field to understand transport and mixing in the
  Bay.
• Strategy First consider reduced models.
• Qualitative Models Simple geometry Emphasis
  on PDEs - Stommel, Munk, Veronis, 2 1/2 layer
  model, Navier-Stokes, nonlinear Ellipitic PDEs
• Complex Geometries 2D and 3D boundaries of the
  Chesapeake Bay. Eigenvalue and Poisson Solvers
• Comparison With Quoddy (NOAA) model

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Stommels model
1948 paper, Key Assumptions 2D, Steady,
Rectangular Basin, Bottom Friction Key Features
Wind stress, Coriolis Key Findings Boundary
Layer (Gulf Stream)

• stream function

Boundary conditions ? 0 on all four boundaries
Scales N. Atlantic Basin 10,000 Km by 6000
Km Depth 200 Meters Coriolis Parameter 10(-13)
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Munks Model
Zero boundary conditions
Multiphysics approach
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Non Rectangular Geometries
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