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Actual Airflow vs. Ideal Airflow: Stalls
FoilSim Activity

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Subject Area: Industrial Technology and Physics

Grade Level: 9-12

National Science Standards:

Science as Inquiry - develop an appreciation of how we know what we know.
Physical Science - motions and forces interactions.

National Technology Standards:

Technology Research Tools - Select and apply technology tools for research, information analysis, problem-solving, and decision-making in content learning.
Technology Problem-Solving and Decision-Making Tools - Routinely and efficiently use on-line information resources to meet needs for collaboration, research, publications, communications, and productivity.


After reading the explanation given below, use 3-D modeling techniques to observe the characteristic signature of the stall condition apparent on an airfoil at high angles of attack. Compare this actual airflow to the ideal airflow depicted in FoilSim and be able to explain the reasons for the results obtained.

FoilSim is an interactive simulation software package that examines the airflow around various shapes of airfoils. As you change parameters such as airspeed, altitude, angle of attack, thickness and curvature of the airfoil, and size of the wing area, the software calculates the lift. The package was created at the NASA Glenn Research Center.

FoilSim II is a Java applet program that executes inside the browser of your computer. It is available on the World Wide Web at You can also download the program to run off-line.

Shown below is a screen shot from the program's controls and displays. You may change the values of the variables by using the slider or the input box on the left of the slider.

To use the slider:

  1. Click the mouse pointer on the arrows at the ends of the slider.
  2. Click the mouse pointer anywhere between the slider and the arrow.
  3. Drag the slider with the mouse.

To use the input box:

Simply select the value in the input box, key in the new value, and press Enter or Tab when finished. The button on the slider will move corresponding to the value typed in the box.

Image of FoilSim Interface

 To begin the activity, click Stalls Activity.


You, or you and your partner(s), will be evaluated on the creation of the model airfoil used, with direct observation of your resulting experiment by the instructor, and by completion of the technical report following this activity.


You will demonstrate the ability to use FoilSim to create a model airfoil that will be tested in a wind tunnel for certain angles of attack. The data will be used to explain differences in actual and ideal airflow in correct report format.


Submitted by:

William Glynn, Brookside High School, Sheffield, Ohio


Related Pages:
Answers FoilSim Activity Index
Aerodynamics Index


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Editor: Tom Benson
NASA Official: Tom Benson
Last Updated: Thu, May 13 02:38:25 PM EDT 2021

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