Overview
This lecture introduces the basic concepts of fluid mechanics, including the definition of fluids, mechanics, and the main branches of fluid mechanics.
Understanding Fluids
- A fluid is any substance that can flow, such as liquids and gases.
- The key characteristic of a fluid is that its molecules are in continuous relative motion.
- Substances like water, milk, and honey are fluids because their molecules move past each other.
- Solids like sugar and flour are not fluids; their particles do not change relative positions over time, despite appearing to "flow" due to gravity.
Basics of Mechanics
- Mechanics is the branch of science that studies forces and their effects (magnitude, direction, etc.).
- When a force is applied to an object, it can cause acceleration or motion.
Introduction to Fluid Mechanics
- Fluid mechanics studies the behavior of fluids under the action of forces.
- It is divided into three main subfields: fluid statics, fluid kinematics, and fluid dynamics.
Subfields of Fluid Mechanics
- Fluid statics: the study of fluids at rest.
- Fluid kinematics: the study of fluids in motion without considering pressure forces.
- Fluid dynamics: the study of fluids in motion while considering pressure forces.
Properties of Fluids (Preview)
- Key fluid properties include density, specific weight, specific volume, specific gravity, viscosity, and surface tension.
- These properties will be discussed in future lectures.
Key Terms & Definitions
- Fluid — A substance whose molecules are in relative motion and can flow (liquids and gases).
- Mechanics — The science of studying forces and their effects.
- Fluid mechanics — The study of fluid behavior under various forces.
- Fluid statics — Study of fluids at rest.
- Fluid kinematics — Study of fluids in motion neglecting pressure forces.
- Fluid dynamics — Study of fluids in motion considering pressure forces.
Action Items / Next Steps
- Review definitions of fluids and the subfields of fluid mechanics.
- Prepare to study properties of fluids (density, viscosity, etc.) in the next lecture.