Tiêu đề Civil Engineering Reviewer - Fluid Mechanics and Hydraulics (Chapter 1).pdf ✅

Civil Engineering Reviewer Fluid Mechanics and Hydraulics Page | 1 Chapter 1 – FLUID PROPERTIES Introduction to Fluid Mechanics Fluid Mechanics – is a study of the behavior of fluids that are either at rest or in motion. Branches of Fluid Mechanics • Hydrostatics – considers the forces acting on a fluid at rest. • Fluid Kinematics – is the study of the geometry of fluid motion. • Fluid Dynamics – considers the forces that cause acceleration of a fluid. Basic Fluid Properties • Density (ρ) – refers to the mass of the fluid that is contained in a unit of volume. ρ = m V ( kg m3 ) • Unit weight or Specific Weight (γ) – refers to the weight of the fluid per unit volume. γ = W V = ρg ( N m3 ) • Specific Gravity (SG) – is the dimensionless quantity that is defined as the ratio of the density or specific weight to that of some other substance that is taken as standard. For solids and liquids: SGo = ρo ρwater = γo γwater For gases: SGgas = ρgas ρair = γgas γair

Civil Engineering Reviewer Fluid Mechanics and Hydraulics Page | 3 • Kinematic Viscosity (ν) – refers to the ratio of the dynamic viscosity (μ) of the fluid to its mass density (ρ). ν = μ ρ ( m2 s ) Note: 1 poise = 0.1 Pa − s 1 stoke = 0.0001 m2⁄s • Surface Tension (σ) – refers to the imaginary film that seems to form on the free surface of a fluid capable of resisting tension. Capillarity – refers to the rise or fall (h) of a fluid in a capillary tube that is caused by the surface tension and depends on the relative magnitudes of the cohesion of the liquid and the adhesion of the liquid to the walls of the containing vessel. h = 4σ cos θ γD Pressure inside a Droplet p = 4σ D Pressure inside a Bubble p = 8σ D