Which principle is NOT part of fluid dynamics?

Vapor pressure is not directly considered a principle of fluid dynamics; rather, it pertains to thermodynamics and the behavior of fluids at different temperatures and states (e.g., liquid and gas). Fluid dynamics primarily focuses on the behavior of fluids in motion and how they interact with forces and environments.

Pressure changes refer to how forces acting on a fluid can change its pressure at various points. Flow patterns involve how fluids move, whether they are laminar or turbulent, and how various factors influence these movements. The impact of viscosity examines how the thickness or resistance to flow of a fluid can affect its movement, influencing the dynamics of fluid behavior significantly.

In the context of fluid dynamics, understanding pressure changes, flow patterns, and viscosity is essential to predicting and analyzing how fluids behave under various conditions, while vapor pressure is more aligned with the properties of fluids in different phases and temperatures rather than how they flow.