# EGA324 Mechanical Engineering Practice: Assignment C1 – Aerofoil Experiment (30%)

This assignment is based on Experiment 1: Flow over an Aerofoil in the subsonic wind tunnel completed during weeks commencing 04-Feb & 11-Feb. The coversheet is given as the first page of this document.

For the final submission remove these guidelines. Restrict yourself to a total 9 page limit1 page coversheet (as given at the start of this document) and 8 pages for technical report.

You are to complete a technical report on the experiment utilising of the following headings, with some guidance provided below (refer to course notes for further details):

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Summary and Objectives

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Brief introduction and aims of experiment

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Key details and findings of the experiment

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Comparison to previously published data (either experimental or computational) and/or theoretical estimates

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Any significant findings claimed in the summary should tally to your discussion and conclusions sections

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Experimental Methodology

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Experimental setup, equipment & apparatus – what was measured during the experiment?

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Criticial specimen dimensions & geomteries

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Experimental progamme detail: independent, dependent and any environmental variables

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Number of repeats to minimise experimental error/uncertainty

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Results

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Refer to the course notes for a more detailed description for the experimental results to be included in this section, primarily an example table of the data collected, pressure distributions over the aerofoil at suggested Angle of Attack (AoA) and drag/lift/lift coefficient graphs as a function of AoA.

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You should also be thinking here of including data in the graphs from theoretical/empirical considerations and/or data from previously published results.

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Discussion

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Are there any appreciable fluctuations in either the recorded measurements?

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Is there any reason to doubt the accuracy of the measured lift and drag forces?

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Can you include a measure of error bars on your experimental data?

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Describe the shape of the pressure distributions over the aerofoil using Bernoulli’s equation.

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Indicate the stall angle and describe how you determined that value.

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Explain your results – what happens to the flow over the aerofoil as it approaches and goes beyond the stall angle? How are the pressure and velocity connected along a streamline?

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Were you able to obtain previous data for comparison at a similar Reynolds number and for the same foil (NACA0012). How do your results compare?

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Conclusions

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The conclusions should summarise the key finsingd of the work such as: Influence of the Reynolds number on the peak lift and drag? Influence of the AoA on the pressure distributions? At what angle of attack did the stall occur, and how was this affected by the Reynolds number? How reliable are your results?

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How does the data compare to any published experimental data?

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How does it compare to theory or empirical equations?

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You are not answering these questions directly, but they help to form the basis of your discussion. Not all questions need necessarily to be answered – just what is relevant and justifiable from your own results.

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References

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Minimum 2-4 references with are relevant, and cited in a consistent and appropriate format such as Harvard or Vancouver.