Chapter 1 Flashcards
Name some physical parameters that can be used to describe a flow.
- Size or characteristic length
- Speed, V
- Pressure, P
Define a fluid.
A fluid is a substance that deforms continuously when acted on by a shearing stress of any magnitude.
Describe the difference between qualitatively and quantitatively with respect to fluid mechanics.
Qualitative: Nature or type of characteristics of the flow. (e.g. Length, time, stress, and velocity)
Quantitative: Provides numerical values to the qualitative.
The qualitative description requires both
A number and a standard or unit.
Definition of a pound with respect to a slug.
1 lb = (1 slug)(1 ft/s^2)
1 slug is how many pounds (lbm)?
32.2lb
What is specific volume?
v = 1/rho where rho is the density.
What are the BG and SI units for specific weight?
BG: lb/ft^3
SI: N/m^3
Give the definition of a Newtonian fluid.
Fluids for which the shearing stress is linearly related to the rate of shearing strain (also referred to as the rate of angular deformation).
Give the definition of a Non-Newtonian fluid.
Fluids for which the shearing stress is NOT linearly related to the rate of shearing strain.
Give the BG and SI units for viscosity.
BG: lbs / ft^2
SI: Ns / m^2
What is the conversion equation between Rankine and Fahrenheit?
R = F + 459.67
Ref: Pg 7
What is the gravitational acceleration in the BG system?
32.2 feet / second^2
Ref: Pg 8
What is the ideal gas equation?
absolute pressure = (density)(the gas constant)(absolute temp)
Ref: Pg 12
True or False
In the ideal gas law, you can use the gauge pressure.
False, absolute pressures must be used.
Ref: Pg 12
What is the relationship between applied force on a body immersed in fluid and shearing stress?
Force = (tao)(area)
Ref: Pg 14
What is the no-slip condition?
A statement of a fluid’s viscosity, which says that the velocity of a fluid is zero at the interface of a solid boundary.
Ref: Pg 14
What is the equation for the rate of shearing strain?
gamma_dot = du/dy
Ref: Pg 15
True or False
The absolute viscosity is the same thing as the dynamic viscosity?
True
Ref: Pg 15
What is the relationship between shear stress and viscosity?
Shear stress = (viscosity)(shearing strain)
or;
(Tao) = (Mu)(du/dy)
Ref: Pg 15
For shear-thinning fluids ____.
The apparent viscosity decreases with increasing shear rate. In other words, the harder the fluid is sheared the less viscous it becomes. Latex-based paints are an example.
Ref: Pg 16
For shear-thickening fluids _____.
The apparent viscosity increases with increasing shear rate–the harder the fluid is sheared the more viscous it becomes. An example would be water mixed with corn starch.
Ref: Pg 16
True or False
A Bingham plastic is neither a solid nor a liquid.
True
Ref: Pg 16
Give two examples of Bingham plastics.
Toothpaste and mayonnaise.
Ref: Pg 16
