Fluid Mechanics Overview

Study Notes

Fluid mechanics studies fluids at rest (fluid statics) and in motion (fluid dynamics).
Fluid behavior is vital in applications such as engineering, meteorology, and aerodynamics.

Fluids can flow and conform to the shape of their containers, unlike solids which maintain shape.
No-slip condition describes the scenario where fluid in contact with a solid surface has zero velocity relative to that surface.

Viscous vs. Inviscid Flow: Viscous flow includes the effects of viscosity, while inviscid flow neglects these effects.
Internal vs. External Flow: Internal flow occurs in confined spaces (like pipes), whereas external flow is over surfaces (like air over an airplane).
Compressible vs. Incompressible Flow: Compressible flow involves significant density changes (like gases), while incompressible flow assumes constant density (like most liquids).

Density remains nearly constant during flow, ensuring the volume of fluid does not change.

Laminar Flow: Smooth and orderly, characterized by low Reynolds number (Re).
Turbulent Flow: Chaotic and irregular, occurring with high Reynolds number; defined by eddies and swirls.

Natural Flow: Driven by natural forces (e.g., buoyancy effects), such as the rise of warm air.
Forced Flow: Achieved by external means (e.g., pumps, fans) to drive fluid movement.
Steady Flow: Fluid properties do not change with time at any point in the fluid.
Unsteady Flow: Fluid properties vary with time at one or more points.

Uniform Flow: Fluid velocity is consistent throughout a flow field.
Non-Uniform Flow: Fluid velocity varies at different locations within the flow.

Quantitative description of fluids necessitates comparative standards for measurements. Both a number and a unit are needed for clarity and communication in scientific contexts.