Wind blows and pasts a banner causes it to flutter. The fluttering frequency f is a function of the wind speed V, the air density ρ, the acceleration of gravity g, the length of the banner L and the “area density” of the flag material ρA (with dimensions of ML-2 ). In order to estimate the flutter frequency of a large banner with L = 40 ft in a V = 30 ft/s wind, a small banner with L = 4 ft is to be tested in a wind tunnel. (a) What is the area density of the small banner when the large banner has area density of 0.006 slugs/ft2? (b) What should the wind tunnel velocity be to test the small model? (c) It has been shown that the small banner flutters at 6 s-1 when the same area density and wind tunnel velocity are used in parts (a) and (b). In this case, what is the fluttering frequency of the large banner?
Wind blows and pasts a banner causes it to flutter. The fluttering frequency f is a function of the wind speed V, the air density ρ, the acceleration of gravity g, the length of the banner L and the “area density” of the flag material ρA (with dimensions of ML-2 ). In order to estimate the flutter frequency of a large banner with L = 40 ft in a V = 30 ft/s wind, a small banner with L = 4 ft is to be tested in a wind tunnel.
(a) What is the area density of the small banner when the large banner has area density of 0.006 slugs/ft2?
(b) What should the wind tunnel velocity be to test the small model?
(c) It has been shown that the small banner flutters at 6 s-1 when the same area density and wind tunnel velocity are used in parts (a) and (b). In this case, what is the fluttering frequency of the large banner?
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