fluid 2 mechanical engineering homework

ME598 – Fall 2014 Problem Set 6 Due Oct 28,2014

ME598 Problem Set 6

Use the code given to do the following problems.

1) Use ClassicThinAirfoilAnalysis.m to numerically solve the lift coefficient

for a NACA 4412 airfoil at 0 degrees angle of attack.

a. Do a sensitivity study to see how many points along the camber

line are needed to converge to a reasonable value.

b. How far off is this value from the experimental value given in

http://www.baylor.edu/content/services/document.php/41147.pdf

c. Where is the center of pressure?

2) For the same airfoil,

a. plot Cl vs alpha - <α< .

i. Is the slope 2*pi as predicted analytically?

b. What angle of attack gives zero lift?

i. This angle can be calculated analytically as -

1/pi*∫

. Find dz/dx using the equation for

the camber line of a NACA 4-digit airfoil and compare

your analytically and numerical values.

c. give a plot of Cl vs Cd.

d. Plot the center of pressure vs angle of attack.

3) Run the simulation for a NACA 0012 airofoil at 0 and 10 degrees of angle

of attack. Is the difference in lift coefficient between the 0012 and 4412

the same for both angles of attack? Should it be?

4) When does the thin airfoil theory fail miserably?

5) Look back at the integral in Question 2bi. Judging from the equation, why

do you think the flaps on airfoils are put on the back of the wing and not

the front?