Consider a rectangular wing mounted in a full-scale wind tunnel. The wing model completely spans the test section so that the fl
ow sees essentially an infinite wing. The wing has a NACA 0009 airfoil section, a chord of 2.0 m, and a span of 5 m. The tunnel is operated at the following test conditions: P = 95,000 N/m2; T =25◦C; V = 70 m/s; and μ = 1.86 × 10^−5 kg/(m s).
a. Determine the operating Reynolds number.
b. Calculate the lift and drag, about the aerodynamic center for an angle of attack of 10 deg. using the most appropriate curve (indicate which curve you used).
c. Assume in the next test, the most appropriate Reynolds number is 6 × 10^6 and the wing has roughness, but the same dimensions, find the following:
i. What velocity is this wing tested at in the wind tunnel?
ii. What is the stalling angle of attack for this airfoil?
iii. What is the angle of attack for zero lift? and 3) what is the lift- curve slope?
iv. Calculate the lift and drag for case c) at the stall angle.
a. Determine the operating Reynolds number.
b. Calculate the lift and drag, about the aerodynamic center for an angle of attack of 10 deg. using the most appropriate curve (indicate which curve you used).
c. Assume in the next test, the most appropriate Reynolds number is 6 × 10^6 and the wing has roughness, but the same dimensions, find the following:
i. What velocity is this wing tested at in the wind tunnel?
ii. What is the stalling angle of attack for this airfoil?
iii. What is the angle of attack for zero lift? and 3) what is the lift- curve slope?
iv. Calculate the lift and drag for case c) at the stall angle.
1 answer:
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Answer:
F = 8552.7N
Explanation:
We need first our values, that are,
We start to calculate the relative velocity, that is,
With the relative velocity we can calculate the mass flow rate, given by,
We need to define the Force in the direction of the flow,
Answer:
Explanation:
First, we will find actual properties at given inlet and outlet states by the use of steam tables:
AT INLET:
At 4MPa and 350°C, from the superheated table:
h₁ = 3093.3 KJ/kg
s₁ = 6.5843 KJ/kg.K
AT OUTLET:
At P₂ = 125 KPa and steam is saturated in vapor state:
h₂ = = 2684.9 KJ/kg
Now, for the isentropic enthalpy, we have:
P₂ = 125 KPa and s₂ = s₁ = 6.5843 KJ/kg.K
Since s₂ is less than and greater than
at 125 KPa. Therefore, the steam is in a saturated mixture state. So:
Now, we will find (enthalpy at the outlet for the isentropic process):
Now, the isentropic efficiency of the turbine can be given as follows: