Velocity:Velocity refers to the speed of something in a given direction. In fluid dynamics, it indicates how fast the fluid particles are moving.
Bernoulli's Equation:$P + \frac{1}{2}\rho v^2 + \rho gh = \text{constant}$; this principle describes the conservation of energy in flowing fluids.
Continuity Equation:$A_1 v_1 = A_2 v_2$; this equation states that for an incompressible fluid, the product of cross-sectional area and velocity remains constant along a streamline.