AAE 33401 Lab 1 Post-Lab Assignment
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Feb 20, 2024
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AAE 33401 Lab 1 Post-Lab Assignment AAE 33
401
Lab 1: Airfoil Characteristics
Post-Lab Assignment Name: Yonghyun Lee Lab Section/Team Color: Gold 5 1. Lab Objectives (5) In 500 words or less, discuss the objectives of this lab and how well they were met and to what extent they were not met. If applicable, discuss reasons why particular objectives were not met during your performance of the lab and how these challenges might be addressed in the future. In this experiment, the main objective was to find lift and drag coefficients of the different types of airfoil at varying angle of attack. During the experiment, we used three different airfoils which are base, flaps, and flaps + slats airfoil to measure the lift and drag coefficients and compare them to the real ones. In my opinion, the overall result of the lab experiment satisfied the objectives. However, I was not able fully rely on the data I got from the airfoils, even though, the lift coefficient plots were showing almost the right trend compared to the real cases. The biggest reason was that I doubted the airfoils would generate lift properly as those airfoils felt too heavy. Similar to my expectations, the values of lift coefficient turned out to be much lower than the real values but I was still satisfied that the trend was similar to the real ones. 2. Data Presentation and Analysis (15 points) (1)
(8 points) Plot the lift coefficient vs. angle of attack and the drag polar for the base airfoil (no flap or slat). Compare these results with the NACA 2415 data posted on Blackboard and discuss possible reasons for any significant differences. Use symbols (no connecting line!) for experimental data. Remember to label the axes and make the font sizes, line thicknesses, symbols, etc. sufficiently large so that the plot can be read easily.
AAE 33401 Lab 1 Post-Lab Assignment The trend of the experimental data plot is similar to the NACA 2415 data. However, the values of lift coefficient for the experimental data is significantly lower than the NACA 2415
’
s. I assume the significant difference comes from the difference in the geometry conditions such as the model could be scaled inappropriately and model can be much heavier compared to the actual scaled airfoil. (2)
(7 points) Plot the lift coefficient vs. angle of attack for all three airfoil configurations on the same plot. Are the results what you expected? Why or why not?
AAE 33401 Lab 1 Post-Lab Assignment The results are most likely what I expected because the values of lift coefficient for the base airfoil should be the lowest while the values of lift coefficient for the flaps and slats + flaps airfoil should be relatively higher. In reality, the flaps and slats + flaps airfoil should indicate almost identical values of lift coefficient until the flap airfoil
’
s stall angle and slats + flaps airfoil will stall later. However, the values of lift coefficient of the flaps and flaps + airfoil in the experimental data show some minor differences. Therefore, overall, the experimental data is somewhat reliable and can be concluded as my expected plots. 3. Error and Uncertainty (10 points) (1)
(8 points) Discuss the sources of error and uncertainty in your results and how large they might be. Estimate the uncertainty of your calculated lift coefficient at a given angle of attack. In my opinion, there could be many sources of error and uncertainty in my results. Those sources of uncertainty and error might be caused during the experiment process or from the difference in geometrical properties in the airfoils. Comparing with the actual values of lift coefficient for these three different airfoils with experimental data, I believe there is a significant difference in the values especially from the fact that the values of lift coefficient for every case is lower than the actual values. (2)
(2 points) What would you change to get better data next time? To improve the data, we need to increase the values of lift coefficient overall. To increase the values of lift coefficient similar to the real values, we first need to improve our airfoil models. I believe the models are too heavy to properly generate the lift as the real airfoils are made out of lighter materials. Therefore,
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AAE 33401 Lab 1 Post-Lab Assignment improve the data, it is very important to scale and copy the real airfoils in terms of materials and geometry.