Aerodynamics Quiz

Question 1

What is the stagnation point ?

Answer 1

Loaction with zero velocity at windward edge of an obstacle

Question 2

Based on which equation is the relation between pressure and velocity described ?

Answer 2

Bernoulli Equation

Question 3

What is the reason for under-pressure on a surface of an object in wind flow ?

Answer 3

Compressed stream lines, increased flow velocity

Question 4

What is the main difference comparing sharp-edged and rounded objects with respect to their aerodynamic behaviour ?

Answer 4

The flow separation of sharp-edged cross section is predefined and independent on scale

Question 5

An average wind speed of 10 m/s is given as undisturbed flow speed (top height of building). Determine the acting (average) surface pressure at a location or which a pressure coefficient of cpe = + 0,8 has been determined.

Answer 5

+ 50,0 N/m^2

Question 6

Near the surface of an object an accelerated flow speed of v/ v(unendlich) = 1,2 has been measured. Which value of the pressure coefficient cpe do you expect?

Answer 6

• 0,44

Question 7

During a severe storm event a gust velocity of v=30 m/s is reached (undisturbed flow) at top height of the building. Determine the acting cladding pressure at the windward side (with sign (+/-) and unit [kN/m^2])

Answer 7

+ 0,56

Question 8

A cross-section with equilateral triangle is faced with its tip towards the wind direction. Please estimate the average drag force coefficient cD.

Answer 8

0,0

Question 9

Comparing the drag force of the 3 different cross-section, please order lowest to highest:

A. Triangular (tip windward)

B. Triangular (edge windward)

C. square

Answer 9

A, C, B

Question 10

Comparing the overall resulting force of a slender and a compact building with same height: what ratio of total force F to the building width b is higher and why?

Answer 10

The slender one has a lower ration of F:b, due to the applicable height profile of the velocity pressure.