APPH 4200 Physics of Fluids - Columbia...
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APPH 4200 Physics of Fluids A Few More Fluid Instabilities (Ch. 12) Turbulence (Ch. 13) December 1, 2011 1. Viscous boundary layer and waves 2. Stability of Parallel Flows 3. Introduction to Turbulence: Lorenz Model 1
Transcript of APPH 4200 Physics of Fluids - Columbia...
APPH 4200 Physics of FluidsA Few More Fluid Instabilities (Ch. 12)
Turbulence (Ch. 13)December 1, 2011
1.!! Viscous boundary layer and waves2.! Stability of Parallel Flows3.! Introduction to Turbulence: Lorenz Model
1
Viscous Boundary Layer above an Oscillating Wall
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2
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Mathematica Notebook
Lorenz_Model.nb
25
Summary• Understanding linear instabilities in fluid dynamics involves three
important steps:
- Continuity and Navier-Stokes
- Statics
- Linear Dynamics
- Reduction using normal modes
- Matching boundary conditions
• Flow shear instabilities can be destabilized by viscosity!
• Nonlinearity, U⋅∇U, can drive chaotic, or turbulent, dynamics
26
