AAE 33401 Lab 2 Post-Lab Assignment

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Feb 20, 2024

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Lab 2 Post-Lab Assignment AAE 33 401 Lab 2 : Pressure Tap Airfoil 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. The main objectives of this lab were to measure the pressure distribution over the airfoil, calculate the lift and drag properties, and observe the transition point. By doing the experiment from the lab, I was able to understand how Cl and Cd are influenced by changing distributions of Cp for different aoa. However, it was hard for me to observe and have a better understanding in the transition point from laminar to turbulent flow. In my opinion, the experiment was too focused on calculations instead of observation. I feel like it is important to help us observe the physical phenomenon of the transition, therefore, we can relate our experimental data and calculations to the observation. Therefore, I hope this challenge can be handled by helping students to observe the transition in their eyes. 2. Data Presentation and Analysis (15 points) (1) (5 points) Plot the C p distributions for all angles of attack on the same plot. Briefly discuss how the pressure distribution changes with the angle of attack.
Lab 2 Post-Lab Assignment As the aoa increases the Cp distributions on the upper and lower surface increase and decrease respectively. From this we can assume that there will be increase in Cl if the gap between the Cp distributions on the upper and lower surfaces gets bigger. (2) (10 points) Use your data to estimate C l and C d at each angle of attack. Plot the C l vs. curve and C l vs. C d (drag polar). By using the data we get Cl Cd -0.518571046 0.0685333834 -0.4179393977 0.04290592677 -0.3352134903 0.02192570878 -0.1295330553 0.003861653976 0.004765227021 0.00001000395622 0.2101871475 0.006186236596 0.3996202771 0.02018405097 0.4826282784 0.0351123824 0.5427479432 0.05432595372 0.6553068875 0.08080494505 0.7722128216 0.1236486001
Lab 2 Post-Lab Assignment 0.7592104646 0.1903205622 0.7240145678 0.2412592546 0.6409706658 0.2372786025 0.6899704138 0.2846548737
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Lab 2 Post-Lab Assignment 3. Comparison with Theoretical Calculations (10 points)
Lab 2 Post-Lab Assignment Compare your results with XFLR5 calculations and experimental results for the NACA 662-215 airfoil (from “Summary of Airfoil Data” by Abbot, von Doenhoff, and Stivers in NACA Report 824) uploaded on the class Blackboard page. Discuss the primary reasons for differences between your data, the XFLR5 calculations, and the historical data. Cl vs aoa
Lab 2 Post-Lab Assignment Cd vs Cl
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Lab 2 Post-Lab Assignment There are some differences between the experimental data plot and XFLR5 data plot. For the Cl vs Alpha, we can see that the overall Cl is higher than from the experimental data. In addition, the stall from the experimental airfoil occurs at lower aoa. For the Cd vs Cl, there is a sudden decrease and increase in Cd between 0 and 0.4 Cl from the experimental data. However, the plot from XFLR5 gives a perfect looking drag bucket. Therefore, we can assume that the difference between these data comes from the fact that XFLR5 uses an infinite type of airfoil while the experimental data uses an infinite airfoil.