Introduction to Fluid Mechanics

Introduction to Fluid Mechanics

• Fluid mechanics is the branch of physics studying the behavior of fluids (liquids and gases) at rest and in motion.
• Phenomena range from blood flow to air around airplanes.
• Key concepts include pressure, viscosity, density, and buoyancy.
• Applications span engineering, medicine, and environmental science.

Fluid Properties

• Density (ρ): Mass per unit volume of a fluid. High-density fluids have more mass for a given space.
• Viscosity (μ): Fluid's resistance to flow. Higher viscosity means greater resistance (e.g., honey vs. water).
• Pressure (P): Force per unit area exerted by a fluid. Pressure increases with depth in a static fluid.
• Specific Gravity: Ratio of a substance's density to water's density at a standard temperature.

Fluid Statics

• Pascal's Law: Pressure in a confined fluid is transmitted equally in all directions.
• Archimedes' Principle: An immersed object experiences an upward buoyant force equal to the weight of the displaced fluid.
• Pressure Variations in Static Fluids: Pressure increases with depth due to the weight of fluid above.
• Manometers and Barometers: Instruments measuring fluid pressure.

Fluid Dynamics

• Fluid Flow: Movement of fluids.
• Laminar Flow: Smooth, orderly fluid flow (parallel layers).
• Turbulent Flow: Chaotic, unpredictable fluid flow (eddies and swirls).
• Streamlines: Lines tracing a fluid particle's path, tangent to instantaneous velocity.
• Continuity Equation: Mass conservation in fluid flow; product of velocity and cross-sectional area is constant in steady flow.
• Bernoulli's Principle: For an incompressible, inviscid fluid along a streamline, the sum of pressure, kinetic, and potential energy per unit mass is constant. This explains airplane lift.
• Viscosity Effects: Viscosity in fluid flow causes energy losses (friction losses).
• Drag and Lift: Fluid forces on immersed bodies; crucial in aerospace and ship design. Lift allows flight, drag slows movement.

Applications of Fluid Mechanics

• Civil Engineering: Designing dams, canals, and pipelines.
• Mechanical Engineering: Designing pumps, turbines, and compressors.
• Aerospace Engineering: Designing airplanes, rockets, and spacecraft.
• Chemical Engineering: Designing chemical processing equipment (reactors, distillation columns).
• Environmental Engineering: Studying river flow and air pollution modeling.
• Biomedical Engineering: Modeling blood flow in the human circulatory system.