1. Conservation of momentum
also known as:
Cauchy’s equation
4 equations, 12 unknowns; need to relate flow field and stress tensor
Relation between stress and strain rate
Navier-Stokes
Equation(s)

2. Boundary Conditions
Determine the actual solution
For example, for a simplified form of:
z = 0 at the surface; positive upward

3. We can specify KINEMATIC and DYNAMIC boundary conditions

4. KINEMATIC boundary conditions
The boundary must remain a material surface for the two media limited by the boundary
velocity normal to the surface is the rate at which the boundary moves
for the ocean’s surface
if boundary is rigid – no flux across boundary

5. DYNAMIC boundary conditions
no slip
free slip
Quadratic stress
linear stress