Question

(a) Find the pressure difference on an airplane wing if air flows over the upper surface with a speed of 114m/s , and along the bottom surface with a speed of 107m/s . (in kPa)

(b) If the area of the wing is 32m2 , what is the net upward force exerted on the wing? (in kN)

Answer 1

Given that  Speed of air at bottom is v1 = 114 m/s

   the speed of air at top is v2 = 107 m/s

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Bernoulli's equation ,

        P1 + (1/2)? v₁² + ?gh = P2 + (1/2)? v₂² + ?gh

        ?P = (1/2)? v₂² -  (1/2)? v₁²

              = (1/2)?(v₂² - v₁²)

              = (1/2)(1.29 kg/m³)(114^2m/s² - 107^2m/s² )

              = 997.815 Pa

              = 0.997 kPa

(b) Upward force exerted on the wing is

              F = ?P*A

                 = (997.815 Pa)(32 m²)

                 = 31930.08 N

                 = 31.93 kN