Fluid dynamics is the subdiscipline of fluid mechanics that studies fluids in motion. Fluids are specifically liquids and gases. The solution of a fluid dynamic problem typically involves calculating for various properties of the fluid, such as velocity, pressure, density, and temperature, as functions of space and time. The discipline has a number of subdisciplines, including aerodynamics (the study of gases) and hydrodynamics (the study of liquids). Fluid dynamics has a wide range of applications. For example, it is used in calculating forces and moments on aircraft, the mass flow rate of petroleum through pipelines, and in prediction of weather patterns, and even in traffic engineering, where traffic is treated as a continuous fluid. Fluid dynamics offers a mathematical structure that u