Chapter 13 Fluids Flashcards

Flashcards about fluid dynamics, density, pressure, buoyancy and related principles and equations.

Fluid

A substance that flows; includes liquids and gases.

Mass Density

The ratio of mass to volume (m/V).

Pressure

Liquids exert forces on the walls of their containers. Pressure is the ratio of the force to the area on which the force is exerted.

Hydrostatic Equilibrium

In hydrostatic equilibrium, a connected liquid rises to the same height in all open regions of the container.

Pascal’s Principle

If the pressure at one point in an incompressible fluid is changed, the pressure at every other point in the fluid changes by the same amount.

Atmospheric Pressure

Gas is compressible, so the air in the atmosphere becomes less dense with increasing altitude.

Barometer

Device used to measure atmospheric pressure.

Buoyancy

The upward force exerted by a liquid on an object immersed in it.

Archimedes’ Principle

A fluid exerts an upward buoyant force on an object immersed in or floating on the fluid. The magnitude of the buoyant force equals the weight of the fluid displaced by the object.

Neutral Buoyancy

Condition where an object neither floats nor sinks, remaining motionless within the fluid.

Displaced Fluid

The fluid that is displaced when an object is immersed in a fluid.

Ideal Fluid

Simplified model of fluid flow assuming the fluid is incompressible and flow is steady.

Steady Flow

Fluid velocity at each point in the fluid is constant; it does not fluctuate or change with time.

Laminar Flow

Smooth fluid flow, with recognizable contours.

Turbulent Flow

Disorganized fluid flow.

Viscosity

Resistance to flow.

Reynolds Number

The ratio of inertial forces to viscous forces.

Equation of continuity

The speed v of an incompressible fluid to the cross-section area A of the tube in which it flows

Volume Flow Rate Q

The rate at which fluid flows through a tube (volume per second).

Streamline

The path or trajectory followed by a “particle of fluid.

Fluid element

A small volume of a fluid, a volume containing many particles of fluid.

Pressure Gradient

A region where there is a change in pressure from one point in the fluid to another.

Bernoulli Effect

The pressure is higher at a point along a stream line where the fluid is moving slower, lower where the fluid is moving faster.

Lift

The upward force on the wing of an airplane that makes flight possible.

Bernoulli's Equation

the relationship between pressure, height and speed of a fluid

Viscosity

The measure of a fluid’s resistance to flow

Poiseuille's Equation

The flow rate equation for a viscous fluid.