Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FINALS > AERODYNAMICS > Flashcards

AERODYNAMICS Flashcards

1
Q

“the property of fluid to resist shearing stress”

A

VISCOSITY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

“the sticky or adhesive characteristic of a fluid”

A

VISCOSITY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

It can also be described in terms of a fluid’s thickness.

A

VISCOSITY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In real life there is a drag force on the sphere tending to retard the motion of the sphere.

A

REAL FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

The flow separates on the rear surface of the sphere, setting up a complicated flow in the wake and causing the pressure on the rear surface to be less than that on the forward surface. Hence, a drag force is exerted on the sphere

A

REAL FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

This is a concept used in physics and engineering to study the behavior of fluids under idealized conditions.

A

FRICTIONLESS FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In reality, all fluids experience some degree of friction and viscosity, which affects their flow and energy transfer.

A

FRICTIONLESS FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

useful as a starting point to understand the basic principles of fluid mechanics, but it is not applicable to real-world situations.

A

FRICTIONLESS FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Another region of __________ (sometimes called potential flow) outside the boundary layer.

A

FRICTIONLESS FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Fluid that experiences no friction or viscosity, meaning that there is no resistance to the flow of the fluid.

A

FRICTIONLESS FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The region of viscous flow which has been retarded owing to friction at the surface.

A

BOUNDARY LAYER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Friction is important. It is the layer near the surface.

A

BOUNDARY LAYER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Thickness grows as the flow moves over the body

A

BOUNDARY LAYER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

More and more of the flow is affected by friction as the distance along the surface increases.

A

BOUNDARY LAYER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The presence of friction creates a shear stress at the surface “τw”.

A

BOUNDARY LAYER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

This shear stress has dimensions of force/area and acts in a direction tangential to the surface.

A

BOUNDARY LAYER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Τw gives rise to a drag force called “skin friction drag”.

A

BOUNDARY LAYER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Where μ is called the ____________ (viscosity of the gas). It has dimensions of mass/(length)(time).

A

Absolute viscosity coefficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

For liquids, μ decreases as T increases. “Oil gets thin when Temp Increases.

A

Absolute viscosity coefficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

But for gases, μ increases as T increases (Air gets “thicker” when temperature is increased).

A

Absolute viscosity coefficient

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Constant value of absolute viscosity coefficient IN METRIC SYSTEM

A

𝜇 = 1.7894x10^−5 𝑘𝑔/𝑚. 𝑠

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Constant value of absolute viscosity coefficient IN ENGLISH SYSTEM

A

𝜇 = 3.7373x10^−7𝑠𝑙𝑢𝑔/𝑓𝑡. s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

TWO BASIC TYPES OF VISCOUS FLOWS

A

LAMINAR FLOW
TURBULENT FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Flow in which the streamlines are smooth and regular and the fluid element moves smoothly along the streamline.

A

LAMINAR FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

-Smooth motion fluid elements in a laminar flow.

A

LAMINAR FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q
  • Flow in which the streamlines break up and a fluid element moves in a random, irregular, and tortuous fashion.
A

TURBULENT FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Tortuous, irregular motion of fluid elements

A

TURBULENT FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Less skin friction drag; pressure drag predominates.

A

LAMINAR FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Unstable, tends to favor flow separation

A

LAMINAR FLOW

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Transition region is closer to leading edge

A

LAMINAR FLOW

31
Q

Thinner boundary layer

A

LAMINAR FLOW

32
Q

Greater skin friction drag.

A

TURBULENT FLOW

33
Q

More stable; disorder is favored by nature

A

TURBULENT FLOW

34
Q

Transition region is farther aft

A

TURBULENT FLOW

35
Q

Thicker boundary layer

A

TURBULENT FLOW

36
Q

It is a measure of the ratio of inertia forces to viscous forces.

A

REYNOLD’S NUMBER

37
Q

Helps determine whether the flows in a body and its scaled version are aerodynamically similar.

A

REYNOLD’S NUMBER

38
Q

Can be applied in determining whether all, or portion of boundary layer is laminar or turbulent.

A

REYNOLD’S NUMBER

39
Q

Dimensionless, It varies linearly with X. Sometimes called a local Reynolds number, because it is based on the local coordinate X.

A

REYNOLD’S NUMBER

40
Q

REYNOLD’S NUMBER
FORMULA

A

𝑅𝑒𝑥 = ρ∞V∞x/µ∞

41
Q

The flow always starts out from the leading edge as laminar. Then, becomes unstable and small “bursts” of turbulent flow begin to grow in the flow.

A

TRANSITION

42
Q

Over a certain region called the ________ region, the boundary layer becomes completely turbulent.

A

TRANSITION

43
Q

Transition is said to take place is the critical value xcr. In turn, xcr allows the definition of a critical Reynolds number for transition as

A

Rexcr = ρ∞V∞cr/µ∞

44
Q

FACTORS AFFECTING TRANSITION FROM LAMINAR TO TURBULENT

A
  1. Increased surface roughness
  2. Increased turbulence in the free stream
  3. Adverse pressure gradients
    4.Heating of the fluid by the surface
  4. Similarity parameters of the flow (Mach Number and Reynold’s Number)
45
Q

Friction also causes another phenomenon, called ___________, which, in turn, creates another source of aerodynamic drag, called pressure drag due to separation (Form Drag).

A

FLOW SEPARATION

46
Q

Two Major Consequences of Separated Flow Over an Airfoil

A
  1. A drastic loss of lift (stalling).
  2. A major increase in drag, caused by pressure drag due to separation.
47
Q

A condition wherein the angle of attack increases beyond a certain point such that the lift begins to decrease.

A

STALL

48
Q

Occurs when the critical angle of attack of the airfoil is exceeded.

A

STALL

49
Q

Typically about 15 degrees, but it may vary significantly depending on the fluid, and Reynolds number.

A

STALL

50
Q

An ideal type of flow in which there is no friction.

A

Frictionless flow

51
Q

The Karman Vortex Street was named after aerodynamicist ________________.

A

Theodor Von Karman

52
Q

A ____________ is a repeating pattern of swirling vortices caused by the unsteady separation of a fluid around blunt bodies.

A

Karman vortex street

53
Q

An _______ is a streamlined body which when set at a suitable angle of attack, produces more lift than drag while also producing a manageable pitching moment.

A

Airfoil

54
Q

An airfoil is said to be _________ if the upper and lower cambers are equal in shape.

A

SYMMETRICAL

55
Q

An airfoil is said to be ___________ if the upper and lower cambers are not equal in shape.

A

ASYMMETRICAL

56
Q

The Precise distance from the Leading edge measured along the chord line.

A

Chord

57
Q

A straight line connecting the leading and trailing edges of an airfoil.

A

Chord Line

58
Q

Locus of all points equidistant from the top and bottom of the airfoil.

A

Mean Camber Line

59
Q

The maximum distance between the chord line and the mean camber line.

A

Camber

60
Q

Maximum distance between the top and bottom surfaces of the wing.

A

Thickness

61
Q

Is the maximum thickness-to-chord ratio.

A

Thickness Ratio

62
Q

The most forward points of the mean camber line.

A

Leading Edge

63
Q

The most rearward points of the mean camber line.

A

Trailing Edge

64
Q

The distance from wing tip to wing tip.

A

Wingspan

65
Q

The area of the projection of the actual outline on the plane of the chord.

A

Wing Area

66
Q

The ratio of the span to the chord. If the wing is not rectangular in shape, it is the square of the spane to the area.

A

Aspect Ratio –

67
Q

Angle between the relative wind and the chord line.

A

Angle of Attack

68
Q

Defined as the component of aerodynamic force perpendicular to the relative wind.

A

Lift

69
Q

Defined as the component of the aerodynamic force parallel to the relative wind.

A

Drag

70
Q

The air far upstream of the airfoil.

A

Relative Wind

71
Q

Developed by the National Advisory Committee for Aeronautics

A

NACA AIRFOIL

72
Q

These are airfoil shapes for aircraft wings.

A

NACA AIRFOIL

73
Q

The shape is described by a series of digits followed by the word _____. Can either be 4, 5, or 6 – digits.

A

NACA

FINALS (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions