Dynamic Flow Flashcards
How are fluids defined?
Fluids are defined by their response to stress.
What is stress?
the distribution of force per unit area
What is strain?
the deformation caused by stress.
What two ways will fluids responds to shear stress or perpendicular forces?
Resist compression (e.g., liquids) Become compressible and easily expandable (e.g., gases)
Both liquids and gases are _______.
Fluids
What are forces associated with fluids (4)?
Gravity, Pressure, Friction, Viscosity
What is friction?
Friction is resistant to flow from surface interaction and is proportional to viscosity.
What is viscosity?
A physical property of a fluid that relates to shear stress to the rate of strain (thickness/ stickiness of a solution)
What is flow?
Is the result of pressure forces in a fluid established by differences in pressure from one point to another, which creates a pressure gradient
What creates a pressure gradient?
Flow
How does flow move?
All flow moves from higher pressure/resistance to lower pressure/resistance.
What is a compressible fluid?
Gas
What is an incompressible fluid?
Liquid
What is the equation for flow?
Defined as the quantity of a fluid passing a point per unit of time. F = the mean flow Q = the quantity t = time. F=Q/t
What are three types of flow?
Laminar, transitional, and turbulent flow
Who describe laminar flow?
Jean Louis Marie Poiseuille
Laminar flow can be thought of as thin layers, laminae, which are all _____ to each other.
parallel
What is laminar flow?
The fluid/gas in contact with the horizontal surface is stationary and al other layers slide over each other with increasing speed, but none of the layers mix
Another name for laminar flow is _______.
Smooth flow
What are examples that show laminar flow?
Substance of high viscosity, slow speed, and in smooth narrow tubes, such as capillaries.
Laminar flow: Where is flow at is greatest point?
Toward the center of the tube (about twice the mean flow rate) and approaches zero at the tube wall.
What must be available to drive laminar flow?
Pressure gradient
What is viscosity a measure of?
Friction “within the fluid”
Laminar flow: where is the viscosity?
Since laminar flow is viewed as thin layers that do not interact with one another, the viscosity will be the friction between the layers. This friction will resist the movement of the layers and therefore resist flow.