Wind Tunnel Studies Exam

Question 1

For which investigations would you model a scaled boundary layer?

A) Press coeff. of a high-rise building in an urban surrounding

B) Force coeff. of a blade cross-section for a wind turbine manufacturer

C) Aerodynamic optimization of an antenna

D) Overall forces for a standardized industrial building

Answer 1

A)
D)

Question 2

Which aspect influence the geometrical scale of a boundary layer wind tunnel test?

A) EIgenfrequency of structure and original

B) Chosen roughness installations in the wind tunnel

C) Gust dimensions of wind tunnel flow compared to original flow

D) Reynolds relation and flow re-attachment

Answer 2

B)
C)

Question 3

Why is it difficult to model all wind effects for a rounded cylinder (e.g. for a wind turbine tower) ?

A) Scruton relation is physically impossible in scaled flow

B) Reynolds relation leads to very large velocities in scaled flow

C) Strouhal relation can´t be fullfilled due to the necessary damping of the model

D) Boundary layer needs to be adjusted dependent on flow velocity

Answer 3

B)

Question 4

What entry values and statistical principle is nowadays used for the determination of pressure coefficients?

A) Average pressures and extreme velocity pressure ( equivalent gust principle)

B) Average and urbulent pressure and peak factor (peak factor method)

C) Extreme pressures and extreme velocity pressure (extreme value method)

D) Extreme pressures and average velocity pressure (weighted extreme concept)

Answer 4

C)