Question

Solve this problem using the lift coefficient, Cl = l/(qS). An airfoil with an planform S = 2 m² is tested in a wind tunnel at sea level at a velocity V = 8 m/s in the test section. If the lift coefficient is equal 1.1, how much lift is generated?

A. 10.78 lb
B. 10.78 N
C. 43.12 N
D. 86.24 N

Answer 1

To solve the problem, we can use the equation for lift coefficient and the given values to calculate the amount of lift generated by the airfoil.

Step-by-step explanation:

To solve this problem, we can use the equation for lift coefficient, Cl = L/(qS), where L is the lift force, q is the dynamic pressure, and S is the planform area of the airfoil. Given that Cl = 1.1, S = 2 m², and V = 8 m/s, we can rearrange the equation to solve for L.

The equation can be rewritten as L = Cl * q * S. The dynamic pressure (q) is given by q = 0.5 * ρ * V^2, where ρ is the air density.

Plugging in the given values, we have q = 0.5 * 1.29 kg/m³ * (8 m/s)^2 = 41.28 N/m². Substituting q, Cl, and S into the equation, we get L = 1.1 * 41.28 N/m² * 2 m² = 90.816 N.

Therefore, the airfoil generates a lift of approximately 90.816 N.