CELE Hydraulics & Fluid Mechanics — Properties of FluidsConcept Map

Concept

Density and Specific Weight

Sub Concepts

• Density (ρ)
• Specific Weight (γ)
• Specific Gravity (s)
• Specific Volume (1/ρ)
• Relationship: γ = ρg

Relationship To Central

Fundamental properties defining mass and weight distribution in fluids

Concept

Viscosity

Sub Concepts

• Dynamic Viscosity (μ)
• Kinematic Viscosity (ν)
• Newton's Law of Viscosity
• Newtonian vs Non-Newtonian Fluids
• Temperature Effects on Viscosity

Relationship To Central

Resistance to flow and shear deformation in fluids

Concept

Surface Tension and Capillarity

Sub Concepts

• Surface Tension (σ)
• Contact Angle (θ)
• Capillary Rise Formula
• Capillary Depression
• Adhesion and Cohesion

Relationship To Central

Interface phenomena affecting fluid behavior in small spaces

Concept

Compressibility

Sub Concepts

• Bulk Modulus of Elasticity (E_B)
• Liquid Incompressibility
• Compressibility Effects
• Pressure-Volume Relationship

Relationship To Central

Ability of fluids to change volume under pressure

Concept

Vapor Pressure

Sub Concepts

• Definition and Significance
• Cavitation Phenomenon
• Temperature Dependence
• Saturation Pressure
• NPSH (Net Positive Suction Head)

Relationship To Central

Pressure condition causing phase change and cavitation

To

Specific Weight

From

Density

Strength

strong

Relationship

γ = ρg; specific weight directly proportional to density multiplied by gravitational acceleration

To

Specific Gravity

From

Specific Weight

Strength

strong

Relationship

s = γ/γ_water; dimensionless ratio relating fluid weight to standard water reference

To

Kinematic Viscosity

From

Dynamic Viscosity

Strength

strong

Relationship

ν = μ/ρ; kinematic viscosity is dynamic viscosity divided by density

To

Shear Stress

From

Viscosity

Strength

strong

Relationship

τ = μ(dv/dy); Newton's law directly links viscosity to shear stress gradient

To

Capillary Rise

From

Surface Tension

Strength

strong

Relationship

h = 4σcosθ/(γd); surface tension drives capillary phenomenon in small tubes

To

Capillary Rise or Depression

From

Contact Angle

Strength

strong

Relationship

θ < 90° causes rise; θ > 90° causes depression; determines direction and magnitude

To

Compressibility

From

Bulk Modulus

Strength

strong

Relationship

E_B = dp/(dρ/ρ); inverse relationship—larger bulk modulus means less compressible

To

Cavitation

From

Vapor Pressure

Strength

strong

Relationship

Cavitation initiates when local pressure drops to vapor pressure; direct cause-effect

To

Pressure Calculations

From

Density

Strength

strong

Relationship

Density determines hydrostatic pressure magnitude; P = ρgh fundamental in statics

To

Energy Loss in Pipes

From

Viscosity

Strength

strong

Relationship

Higher viscosity increases friction losses; Hagen-Poiseuille and Darcy-Weisbach depend on μ

To

Viscosity

From

Temperature

Strength

strong

Relationship

Viscosity decreases exponentially with temperature increase for most liquids

To

Vapor Pressure

From

Temperature

Strength

strong

Relationship

Vapor pressure increases non-linearly with temperature; critical for pump suction conditions

To

Hydrostatic Force

From

Specific Weight

Strength

strong

Relationship

F = γhA; hydrostatic force proportional to specific weight and depth

To

Reynolds Number

From

Kinematic Viscosity

Strength

moderate

Relationship

Re = vD/ν; kinematic viscosity determines laminar-turbulent transition

To

Pressure Waves

From

Compressibility

Strength

moderate

Relationship

Bulk modulus affects acoustic wave velocity in fluid; a = √(E_B/ρ)

To

Bubble Formation

From

Surface Tension

Strength

moderate

Relationship

Surface tension resists bubble formation; influences cavitation bubble dynamics

To

NPSH Requirement

From

Vapor Pressure

Strength

strong

Relationship

NPSH_required designed to maintain pressure above vapor pressure; prevents cavitation

To

Dynamic Viscosity Constant

From

Newtonian Fluid Property

Strength

strong

Relationship

Defining characteristic: μ independent of shear rate; permits linear stress-strain relationship