Fundamentals of Fluid Dynamics: Governing Equations and CFD Applications

Fluid dynamics is the study of fluids (liquids and gases) in motion and is governed by a set of fundamental physical laws. The key governing equations include the continuity equation (conservation of mass), the Navier–Stokes equations (conservation of momentum), and the energy equation (conservation of energy). These equations are derived from Newton’s laws of motion and thermodynamic principles, forming a system of nonlinear partial differential equations that describe how velocity, pressure, temperature, and density of a fluid evolve over time and space. Due to the complexity of solving these equations analytically, especially for turbulent or complex flow domains, Computational Fluid Dynamics (CFD) has become an essential tool. CFD uses numerical methods and algorithms to simulate fluid flow, enabling engineers and scientists to analyze performance, optimize designs, and predict behavior in applications ranging from aerospace and automotive engineering to environmental modeling and biomedical devices.