Chapter 7  Some Mathematics: The Equations of Motion
7.9 Important Concepts
 Gravity, buoyancy, and wind are the dominant forces acting on the ocean.
 Earth's rotation produces a pseudo force, the Coriolis force.
 Conservation laws applied to flow in the ocean lead to equations of motion;
conservation of salt, volume and other quantities can lead to deep insights
into oceanic flow.
 The transformation from equations of motion applied to fluid parcels to
equations applied at a fixed point in space greatly complicates the equations
of motion. The linear, firstorder, ordinary differential equations describing
Newtonian dynamics of a mass accelerated by a force become nonlinear, partial
differential equations of fluid mechanics.
 Flow in the ocean can be assumed to be incompressible except when describing
sound. Density can be assumed to be constant except when density is multiplied
by gravity g. The assumption is called the
Boussinesq approximation.
 Conservation of mass leads to the continuity equation, which has an especially
simple form for an incompressible fluid.
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