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TunnelSys - Tunnel Test Applet Version 1.0a


This is a beta 1.0a version of the TunnelSys Tunnel Test Applet program, and you are invited to participate in the beta testing. If you find errors in the program or would like to suggest improvements, please send an e-mail to

Due to IT security concerns, many users are currently experiencing problems running NASA Glenn educational applets. The applets are slowly being updated, but it is a lengthy process. If you are familiar with Java Runtime Environments (JRE), you may want to try downloading the applet and running it on an Integrated Development Environment (IDE) such as Netbeans or Eclipse. The following are tutorials for running Java applets on either IDE:

This page contains an interactive Java applet to explore the operation of a wind tunne. All of the information presented by the applet are available within the Beginner's Guide to Wind Tunnels. You should start with the slide describing the design of a wind tunnel.

TunnelSys - Tunnel Test Applet

With this software you can investigate the process of wind tunnel testing by changing the conditions of a test of a representative wing model. You can look at surface pressure distributions, probe the flow field, and use several flow visualization techniques.

TunnelSys is a series of three Java applications which students can use to explore the process of wind tunel testing. In wind tunnel testing, an engineer must first design and build a wind tunnel model with all of the appropriate instrumentation included. The model is then placed in the tunnel test section and air is blown over the model. Different diagnostic techniques may be employed during a wind tunnel test. The instrumentation records the desired information for the model designer. The engineer who conducts the wind tunnel test is not normally the same person who designed the model, but someone who is a specialist at wind tunnel operation. The data from the test normally goes to a third engineer who performs the necessary data reduction and produces performance plots for the initial engineer.

To demonstrate the process used to conduct wind tunnel testing, we have produced an applet version of TunnelSys. Because of security limitations with Java, you can not save designs or results produced with the applet version. The full application version does permit a team of students to work on the various systems engineering aspects of wind tunnel testing. The applet at the top of this page is the Tunnel Test portion of the TunnelSys applet and application. It is presented here so that students can gain familiarity with the testing part of the process.

This version of the Tunnel Test applet includes an on-line user's manual which describes the various options available in the program and includes hyperlinks to pages in the Beginner's Guide to Wind Tunnels describing the math and science of wind tunnels. More experienced users can select a version of the program which does not include these instructions and loads faster on your computer. You can download these versions of the program to your computer by clicking on this yellow button:

Button to Download a Copy of the Program

With the downloaded version, you can run the program off-line and do not have to be connected to the Internet.


This program is designed to be interactive, so you have to work with the program. There are a variety of choices which you must make regarding the display of results by using a choice box. A choice box has a descriptive word displayed and an arrow at the right of the box. To make a choice, click on the arrow, hold down and drag to make your selection. The current values of the design variables are presented to you in boxes. By convention, a white box with black numbers is an input box and you can change the value of the number. A black box with yellow or green numbers is an output box and the value is computed by the program. To change the value in an input box, select the box by moving the cursor into the box and clicking the mouse, then backspace over the old number, enter a new number, then hit the Enter key on your keyboard. You must hit Enter to send the new value to the program. For most input variables you can also use a slider located next to the input box. Click on the slider bar, hold down and drag the slider bar to change values, or you can click on the arrows at either end of the slider.

If you see only a grey box at the top of this page, be sure that Java is enabled in your browser. If Java is enabled, and you are using the Windows XP operating system, you need to get a newer version of Java. Go to this link:, try the "Download It Now" button, and then select "Yes" when the download box from Sun pops up.

If you experience difficulties when using the sliders to change variables, simply click away from the slider and then back to it. If the arrows on the end of the sliders disappear, click in the areas where the left and right arrow images should appear, and they should reappear.


The program screen is divided into five main parts:

  1. On the top left side of the screen is the View Window. The view window includes a graphic of a wing model in a wind tunnel. During the test, the view in the tunnnel will change depending on your inputs. You can view either a solid model or a transparent model by selecting the buttons below the graphics. The yellow-lighted button is your selection.
  2. On the top right side of the screen is the Diagnostics Window for your model. You can choose to display either the surface pressure or velocity by selecting the button below the window. There are three lines plotted on the screen; the yellow line is the surface distribution of the flow variable on the lower surface of the model, the magenta line is the distribution on the upper surface, and the green line is the reference value for the free stream conditions.
  3. On the lower left side of the screen is the Input Panel. Details of the variables are given below. There are also some selection buttons for Flow Visualization. You can choose to display smoke traces, particle traces, or no trace in the view window by clicking on the appropriate button. Calculations can be performed in either Imperial or Metric units by using the choice button.
  4. On the middle right side of the screen is the Probe Panel. Details of the probe operation are given below.
  5. On the lower right side of the screen is the Output Panel. Details of the output variables are given below.


The Probe Panel contains a computer drawing of an output gauge and some buttons to the left. By default, the probe is turned off. You turn the probe on by pushing one of the white buttons on the Probe Panel. The probe itself will then appear in the View Window. You change the location of the probe using the sliders to the left and below the gauge on the Probe Panel. The value of the pressure or the velocity at the location of the probe tip (magenta ball on the view window) is displayed on the gauge. Or a green trail of "smoke" is swept downstream from the probe location. You turn the probe off by using the red button.


The input variables are located on the panel that is displayed at the lower left below the View Window. There are three input variables; the speed of the flow, the angle of attack of the model, and the tunnel static pressure. As you vary any of the input variables, the resulting orientation is shown in the View Window, the values of the surface variable are shown in the Diagnostic Window, and the computed lift is shown on the Output Panel. By default, the program begins with no flow through the tunnel. Notice that for this version of TunnelSys you can not change the shape of the wing being tested. In the full system version you can put different wing designs in the tunnel.


The output variables are located on the panel that is displayed at the lower right below the Probe Panel. The chief output from the program is the computed the lift of the wing. The lift depends on the tunnel conditions so the dynamic and total pressure in the tunnel are also displayed. For the full system version, as you load different wing designs, the output panel gives a description of the wing geometry.


The Education Programs Office will continue to improve and update TunnelSys based on user input. Changes from previous versions of the program include:

  1. On 5 Aug 09, version 1.0a was released. This is the first released version of the program.

Guided Tours


Button to Display Wind Tunnel Index Button to Display Aerodynamics Index
Beginner's Guide to Wind Tunnels
Beginner's Guide to Aeronautics


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Editor: Nancy Hall
NASA Official: Nancy Hall
Last Updated: May 13 2021

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