

          TunnelSys Wind Tunnel Test Application



This is the beta 1.0j version of the NASA Glenn TunnelSys 
Wind Tunnel Test application program, and you are invited to participate 
in the beta testing. If you find any errors in the program or would like to suggest
improvements, please send an e-mail to Thomas.J.Benson@nasa.gov.

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 
record the lift generated by your wing model. You can run sequences of tests by
varying the speed, angle of attack, or pressure within the tunnel.

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 and 
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 goes to a third engineer who performs the necessary
data reduction and produces performance plots for the initial engineer. 

RUNNING THE APPLICATION

This program is a Java application and you must have the Java JDK installed on your computer
to operate the program. An application works differently than a Java applet
available on the Internet. This program runs "stand-alone" and can read and write
files to your computer. To launch the program, you need to know the PATH to the
folder where the program has been extracted. The PATH will be something like
C:\My Programs\TunnelSys\wtest
To launch the application, go to C:\      
Assuming you have Java installed on your computer, type this command:

    java -cp (the PATH) Tunnel

for our example PATH, this would look like:

    java -cp My Programs\TunnelSys\wtest Tunnel


GENERAL INSTRUCTIONS

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 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.
At any time, to return to the original default conditions,
click the magenta <b>Reset</b> button at the lower left of the program.

SCREEN LAYOUT

The program screen is divided into five main parts:
     
   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.
  
   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.
  
   On the lower left side of the screen is the Input Panel.
   Details of the input variables are given below in the "Input" section and
   in the "Saving Results" section. 
   Calculations can be performed in either Imperial or Metric units by using the choice button.
   At any time you may click on the "Reset" button and restart the program.
             
   On the middle right side of the screen is the Probe Panel.
   Details of the probe operation are given below in the "Probe" section.

   On the lower right side of the screen is the Output Panel.
   Details of the output variables are given in the "Output" section.

PROBE

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.

INPUT
   
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. 

You begin a wind tunnel test by loading geometry data from the Design Program.
Click on the blue button "Model File" to open a browser where you can locate the
data file generated by the Design Program. 
The form of this browser depends on your particular operating system.
We recommend that you create some naming conventions so that you can easily find your files.
You may want to create a special directory for each student. When you return from the browser,
the path to your model file will be entered into the text box to the right of the "Open File" button.
You must click "Open File" to open the model file. The number of wing models generated by
the Design Program will be listed in the text box.

You next select a wing to test by entering the "Model #" on the panel to the right
below the probe gauge. You then click "Install Model" and the model will be placed
in the test section of the tunnel and the shape of the model in the
view window will change. The details of the model design are loaded into the output panel as
described below.

SAVING RESULTS

You will want to save your wind tunnel test results in order to pass the information to the 
the post-processing program. Test results are saved in files on your computer.
There are two types of files that can be saved from the Wind Tunnel test Program; a data file that 
is used as input to the Post Processing Program, and a printed file for your records.

For the Data file, click on the blue "Data File" button. This will open a "browser" that you can use to
locate and name the data file. When you return from the browser,
the path to your data file will be entered into the text box to the right of the "Open Data" button.
You then must click "Open Data" to open the file and begin the tunnel test process discussed below.

A similar procedure is used to name and open the "Print File".  It is not necessary to create and
open a print file. The print file is just for your records.

TEST PROCESS

You now set the values of the flow variables on the Input Panel using the input boxes or sliders.
You select which flow variable you are going to change while holding the other 
variables fixed during a test. You indicate the choice by clicking on the blue buttons labeled "Select Test".
Next you click the "Begin Test" button, then set the selected variable value to the initial value.
Click "Take Data Point" and the "Point #" will increase by one. Set the next value of the
input variable and again click "Take Data Point".  Continue this process until you are finished
with this test, then click "End Test". You may now select a new test, or install a 
different model and begin the process all over again. When you have finished all of your tests,
click the "Exit" button.

OUTPUT

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 lift of the wing.
The lift depends on the tunnel conditions so the dynamic and total pressure
in the tunnel are also displayed. As you load different wing designs, the output panel
gives a description of the wing geometry in terms of camber, chord, thickness, area and aspect ratio.


When your testing is completed, you are ready for the post-processing program.
