fluid mechanics
Incompressible Navier-Stokes Eqns.
$$\frac{\partial u}{\partial x} + \frac{\partial v}{\partial y} + \frac{\partial w}{\partial z} = 0$$
Kinematic Viscosity
$$
u = \frac{\mu}{\rho}$$
Bernoulli's Principle
$$P + \frac{1}{2} \rho v^2 + \rho g h = \text{const}$$
Hydrostatic Equation
$$\frac{dP}{dz} = - \rho g$$
Specific Gravity
$$SG = \frac{\rho}{\rho_{H_2O}}$$
Specific Weight
$$\gamma = \rho g$$
Viscosity
$$\tau = \mu \frac{\partial u}{\partial y}$$