In physics, **fluid dynamics** is a subdiscipline of fluid mechanics that deals with **fluid flow**—the natural science of fluids (liquids and gases) in motion. It has several subdisciplines itself, including **aerodynamics** (the study of air and other gases in motion) and **hydrodynamics**(the study of liquids in motion). Fluid dynamics has a wide range of applications, including calculating forces and moments on aircraft, determining the mass flow rate of petroleum through pipelines, predicting weather patterns, understanding nebulae in interstellar space and modeling fission weapon detonation. Some of its principles are even used in traffic engineering, where traffic is treated as a continuous fluid, and crowd dynamics.

Fluid dynamics offers a systematic structure—which underlies these practical disciplines—that embraces empirical and semi-empirical laws derived from flow measurement and used to solve practical problems. The solution to a fluid dynamics problem typically involves calculating various properties of the fluid, such as flow velocity, pressure, density, and temperature, as functions of space and time.

Before the twentieth century, *hydrodynamics* was synonymous with fluid dynamics. This is still reflected in names of some fluid dynamics topics, like magnetohydrodynamics and hydrodynamic stability, both of which can also be applied to gases.

Topical Notes, Topical Notes, Problems, Presentations, Quiz, Test, Investigations and Videos |

Density |

Pressure: Atmospheric and Fluid pressure |

Pascal’s Principle |

Buoyant Force |

Archimedes’ Principle |

Flow Rate |

Continuity Equation |

Bernoulli’s Principle |

Test your Understanding: Chapter 5 MCQ Quiz 1 Here Take Chapter 5 ReQuiz MCQ Quiz 2 Here |

### Fields of study

- Acoustic theory
- Aerodynamics
- Aeroelasticity
- Aeronautics
- Computational fluid dynamics
- Flow measurement
- Geophysical fluid dynamics
- Hemodynamics
- Hydraulics
- Hydrology
- Hydrostatics
- Electrohydrodynamics
- Magnetohydrodynamics
- Metal fluid dynamics
- Rheology
- Quantum hydrodynamics