1. Conservation of momentum also known as: Cauchy’s equation Relation between stress and strain rate 4 equations, 12 unknowns; need to relate flow field and stress tensor Navier-StokesEquation(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 if boundary is rigid – no flux across boundary velocity normal to the surface is the rate at which the boundary moves for the ocean’s surface

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