Fluid Dynamics Final Exam - Quiz Questions From Class

concepts for final exam

True or False: Gases are considered fluids

True

True or False: Fluids permanently resist a shear stress

False

Gasoline is less dense than water, and thus has a specific gravity that is (blank) 1

less than

A stress has units of

force per area

True or False: toothpaste is a fluid

True

When plotting shear rate vs. shear stress for a Newtonian fluid, the slope represents the (blank) of the fluid

viscosity

True or False: Bingham fluids can completely resist a small amount of shear stress

True

Which type of fluid has an increasing viscosity at higher shear rates: Dilatant, Bingham, or Newtonian?

Dilatant

Which fluid property has units of centipoise?

absolute viscosity

True or False: the viscosity of liquids increases with increasing temperature

False

True or False: It is possible to have a negative gauge pressure

True

Given that the SG of olive oil is 0.91 and the SG of gasoline is 0.74, is a mixture of water, olive oil, and gasoline were created and allowed to settle, what would be the order of layers from top to bottom?

Gasoline, olive oil, water

What is the correct conversion between lbm-ft/s² and lbf?

1lbf = 32.2 lbm-ft/s²

True or False: The general form of the barometric equation dP/dz = -pg indicates what pressure in a fluid decreases moving upward within the fluid

True

True or False: The barometric equation only applies for stagnant fluids

True

True or False: The pressure of a liquid acting on a vertical surface can be assumed constant over the entire surface

False

True or False: The pressure of a gas acting on a vertical surface can be assumed constant over the entire surface.

True

True or False: liquids are generally considered incompressible

True

At high elevations in the atmosphere, which assumption would you expect to yield a high calculated P: isothermal or isentropic?

Calculated P is higher when assuming isothermal

Spongebob is submerged in 4ft of freshwater, while Patrick is submerged in 4ft of seawater (SG = 1.025). Who experiences the greater pressure force on the bottom of their feet?

Patrick

True or False: Water flowing down a street at a constant acceleration is an example of rigid-body motion

False

True or False: You are driving your car at a constant acceleration with a fish tank full of water in your trunk. The water in the fish tank is in rigid-body motion

True

Superman accelerates upwards from the ground holding a gallon of milk. Compared to the pressure of the milk at the bottom of the container when Superman is at rest, the pressure of the milk at the bottom of the container while Superman accelerates upwards is: greater, less, the same?

greater

A horizontal storage tank of oil filled halfway is on a transportation truck at rest. Compared to the pressure of the oil in the bottom back corner of the tank (i.e. back of the truck), the pressure of the oil in the bottom front corner of tank (i.e. front of the truck) is: the same, less, greater?

the same

A horizontal storage tank of oil filled halfway is on a transportation truck accelerating forward. Compared to the pressure of the oil in the bathroom back corner of the tank (i.e. back of the truck), the pressure of the oil in the bottom front corner of the tank (i.e. front of the truck) is: greater, the same, less?

less

At steady state, which of the following is equal to 0?

the rate of accumulation of mass inside a system

For a “real” flow rate of water inside a pip at a given cross-sectional area, which velocity is greater: v at pipe wall, v in middle of pipe, all are same?

the velocity in the middle of the pipe

When assuming “block flow” for a flow rate of water inside a pipe at a given cross-sectional area, which velocity is greater: v at pipe wall, v in middle of pipe, all are the same?

the velocities are the same

True or False: for a constant density fluid flowing through a pipe, the volumetric flow rate is constant at the inlet and outlet

True

True or False: for a compressible fluid flowing through a pipe, the volumetric flow rate is constant at the inlet and outlet

False

Which of the following is equal to the product of density times velocity times cross sectional area?

mass flow rate

True or False: the final form of the BE is derived assuming steady flow

True

For an incompressible fluid in steady state flow at constant T and P, a decrease in pipe diameter leads to (blank) in fluid velocity

an increase

A positive value for non-flow work implies that work is done (blank) the system

on

Which of the following are plausible units for specific gravity? Joules/kg, Joules, or Newtons?

Joules/kg

For which fluid flow scenario is frictional losses the largest? A sudden expansion, a diffuser, both are the same, or not enough info?

A sudden expansion

True or False: The final form of the BE is derived assuming incompressible flow

True

The pressure of a fluid going into a diffuser is (blank) the pressure of the fluid coming out of the diffuser

less than

The pressure of a fluid going into a tank (i.e. a sudden expansion) is (blank) the pressure of the fluid in the tank

equal to

True or False: The BE does a reasonable job modeling the pressure and velocity profile of a low-velocity gas

True

What is the purpose of the static tube in a pitot-static tube? to measure the pressure of the stationary fluid, to help connect the pitot port to the static port, to measure the pressure of the flowing fluid, or does it serve no purpose?

to measure the pressure of the stationary fluid

True or False: The BE does not apply to fluids with high densities

False

Which of the following is NOT an assumption used to derive Torricelli’s Equation? There is no change in height between states 1 and 2, the pressure at states 1 and 2 are equal, there is no initial velocity, there is no non-flow work or friction involved?

There is no change in height between states 1 and 2

True or False: A pitot tube is a quick and easy way to determine the velocity of liquid flow in an open-channel

True

When there is a sudden expansion, the fluid flowing into the tank has (blank) pressure compared to the pressure of the fluid inside the tank: higher, lower, or about the same

about the same

In a venturi meter, the pressure in the throat (i.e. the smaller diameter region) is (blank) the pressure in the cone (i.e. the higher diameter region)

less than

Which of the following fluid-flow measuring devices does not rely on a pressure measuring device? Pitot tube, pitot-static tube, venturi meter, they all rely on a device

pitot tube

True or False: For a venturi meter, frictional losses are not accounted for

False

Which of the following properties are NOT part of the Reynolds number? density viscosity pressure or velocity

pressure

True or False: The Reynolds number is dimensionless

True

True or False: the volumetric flow rate of a fluid through a rotameter is proportional to the height of the rotameter ball

True

True or False: the velocity of a fluid draining from an infinitely large tank is independent of the nozzle diameter

True

Which of the following is not dependent on the diameter of the hole in an orifice plate? velocity, coefficient of discharge, pressure drop through the orifice, all of the above

all of the above

When applying the BE to a venturi meter or orifice plate, which scenario does not result in a “trial and error” approach?

solving for pressure drop (given velocity and diameters)

True or False: Assuming the same volumetric flow rates, flowing nitrogen gas will lift a rotameter ball higher than flowing water will

False

Which of the following does NOT have an impact on frictional losses? changes in pipe diameter, pipe roughness, fluid viscosity, fluid velocity, or all of the above impact frictional losses

all of the above impact frictional losses

Which flow regime is characterized by crosswise mixing of fluid layers?

turbulent flow

Which flow regime is characterized by high Reynolds numbers for flow in a circular pipe

turbulent

In which flow regime is the pressure drop per pipe length linearly proportional to the volumetric flow rate?

laminar flow

Which flow regime yields an unstable relationship between pressure drop per pipe length and volumetric flow rate?

transition flow

Which flow regime are frictional losses greatest

turbulent

For which flow regime is the final equation for frictional losses derived with theory (i.e. not relying on experimental data)

laminar

Describe the friction factor, f

a proportionality constant relating frictional losses to pipe and flow characteristics

True or False: the fanning friction factor increases with increasing Reynolds number

False

True or False: Relative roughness, e/D, is unitless and is a ratio of the particle size to the pipe diameter

True

True or False: the fanning friction factor is higher for smooth pipes than it is for rougher pipes

False

Consider the transfer of oil from one tank to another. Tank 1 is closed and has a pressure of 30 psig with gas above the oil. the pipe connecting the tanks is 250ft and z1=z2. Tank 2 is at atmospheric pressure due to it having a vent on top. What type of gradient is responsible for moving the fluid?

pressure gradient

Consider the transfer of oil from one tank to another. Tank 1 is closed and has a pressure of 30 psig with gas above the oil. the pipe connecting the tanks is 250ft and z1=z2. Tank 2 is at atmospheric pressure due to it having a vent on top. If the pipe was extended to become 500ft long, the frictional losses would (blank)

increase

Consider the transfer of oil from one tank to another. Tank 1 is closed and has a pressure of 30 psig with gas above the oil. the pipe connecting the tanks is 250ft and z1=z2. Tank 2 is at atmospheric pressure due to it having a vent on top. If the pipe was used in this same process 10 years later, frictional losses would:

increase

Consider the transfer of oil from one tank to another. Tank 1 is closed and has a pressure of 30 psig with gas above the oil. the pipe connecting the tanks is 250ft and z1=z2. Tank 2 is at atmospheric pressure due to it having a vent on top. If a heavier fluid were used at the same conditions, the friction factor would:

decrease

True or False: a throttling (i.e. control) valve has a higher frictional loss than an on/off valve

True

True or False: a sudden contraction has a higher frictional loss than a sudden expansion

False

Define equivalent length

the relative length of a straight pipe frictional losses incurred by a fitting or valve

What is not a minor frictional loss: flow through a globe valve, flow through a pipe diameter expansion, flow through a 90-degree turn, flow through a concrete pipe

flow through a concrete pipe

True or False: using the resistance method or the equivalent length method usually results in the same calculated frictional loss

False

True or False: pump efficiency is defined as useful work divided by useless work

False

True or False: pump head (H) has units of length and represents the pressure increase achieved by a pump

True

Positive displacement pumps create (blank)

flow

Centrifugal pumps create (blank)

velocity