MEE 311 - Fluid Mechanics I (Unit 1.1 & Unit 1.2)

Fill-in-the-blank flashcards covering introduction and properties of fluids from Units 1.1 and 1.2.

A fluid is defined as a substance which continually deforms under a small amount of shear stress. In other words, a fluid does not permanently distortion.

resist

Fluid mechanics is a discipline within the Field of Applied Mechanics that is concerned with the behaviour of fluids (liquids and gases) at or in motion.

REST

The governing laws of Fluid Mechanics include the law of conservation of mass, the laws of mechanics, and the laws of .

thermodynamics

Fluid statics studies fluids in equilibrium state of no stress.

shear

Within Fluid Dynamics, motion is often described as Fluid Kinematics describes motion without , then apply forces to obtain the equations of motion.

forces

A Newtonian Fluid has a viscosity.

constant

An Ideal Fluid is incompressible and has no .

viscosity

A Real Fluid possesses some .

viscosity

A Non–Newtonian Fluid has viscosity.

varying

An Incompressible Fluid has constant .

density

An Inviscid Fluid is a fluid of zero and constant or variable density.

viscosity

Incompressible Flow – Mach Number less than .

0.3

Compressible Subsonic Flow – Mach Number between and 1.

0.3

Transonic Flow – Mach Number between just less than 1 and just more than .

1

Supersonic Flows – Mach Number greater than 1 but less than .

7

Hypersonic Flows – Mach Number greater than .

7

Density is the mass per unit of a substance.

volume

Specific Volume is the volume of fluid occupied by a unit mass of the fluid, i.e., the inverse of .

density

Specific Weight γ is the weight per unit of a fluid.

volume

Specific Gravity SG equals ρ/ρref; if SG is known, the density ρ = SG × ρref. Therefore, ρ = × ρ_ref.

SG

Ideal-gas equation of state is .

P = ρ R T

Saturation Temperature Tsat is the temperature at which a pure substance changes phase at a given _.

pressure

Saturation Pressure Psat is the pressure at which a pure substance changes phase at a given _.

temperature

Vapour Pressure Pv is the pressure exerted by its vapour in phase equilibrium with its liquid at a given _.

temperature

Partial Pressure is the pressure of a gas or vapour in a mixture with other .

gases

Cavitation occurs when the liquid pressure drops below the liquid's pressure.

vapour

Viscosity is the property of a fluid which offers resistance to the movement of one layer of fluid over another; the drag force depends in part on .

viscosity

In Newton’s Law of Viscosity, the rate of deformation is proportional to the stress.

shear

The SI unit of viscosity is the Poise; 1 N·s/m^2 equals Poise.

10

Kinematic viscosity ν is defined as ν = μ/ρ and has units of .

m^2/s

Bulk Modulus K is defined as the ratio of compressive stress to volumetric strain: K = -V dP/dV; thus, K is the ratio of compressive stress to strain.

volumetric

Compressibility is the inverse of bulk modulus; κ = .

1/K

Surface Tension σ is the tensile force acting on the surface of a liquid, measured as force per unit of the free surface.

length

Surface Tension is denoted by the Greek letter .

sigma

Capillary Rise height in a tube is given by h = (2 σ cos θ) / (ρ g d), showing that h is inversely proportional to the tube .

diameter

From the capillary rise expression, increasing σ or decreasing d will the rise.

increase

Capillary Rise equilibrium involves the balance between the weight of the liquid column and the vertical component of the surface tension force along the tube wall; this vertical force is proportional to the tube circumference, which depends on the tube .

diameter

Capillary rise depends on the contact angle; the term cos θ appears in the expression, where θ is the angle between the liquid and the tube.

contact

Capillary rise in a glass tube is affected by the liquid wetting the tube; in mercury, the level in the tube will be than the level outside.

lower

The Vapour Pressure Pv is identical to the Saturation Pressure Psat for a pure substance when the system is in phase with its liquid.

equilibrium

The density of water is approximately kg/m^3.

1000