This is a beta 1.5a version of the FoilSimU II 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 firstname.lastname@example.org.
With this software you can investigate how an aircraft wing produces lift by changing the values of different factors that affect lift.
There are several different versions of FoilSim II which require different levels of experience with the package, knowledge of aerodynamics, and computer technology. This web page contains the off-line university version of the program. It includes an off-line user's manual which describes the various options available in the program. More experienced users can select a version of the program which does not include these instructions and loads faster on your computer.
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 analysis and 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 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. At any time, to return to the original default conditions, click the red Reset button at the upper right of the program.
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: http://www.java.com/en/index.jsp, 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 four main parts:
The View Window contains a schematic drawing of the wing that you are designing and some buttons to control the schematic drawing. Possible choices are colored blue while the selected option is colored yellow.
There are several different output options available for the Output Window at the lower right. You select the type of output by using the red choice box on the control panel. If you select Plot, a graph will appear in the window. The type of graph is described below. Plot Selection provides a panel in the output window which allows you to select the type of plot. If you display a plot and begin to change the input variables, it may become necessary to rescale the plot axes by pushing the white Rescale button at the upper left of the window. The types of available plots are listed below.
The Lift Meter shows the current value of lift (or lift coefficient) displayed in scientific notation. The meter is displayed in the output window and moves as the lift is varied.
The Probe lets you explore the flow around the wing. A probe control panel appears in the output window when you select "Probe" from the control panel. 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 located above the gauge.
The Performance option provides a written list of important input and computed variables in the Output Window. You have two options for performance output; the Data option gives the computed lift and flow conditions, the Geom option shows the coordinates of the airfoil geometry and the local value of velocity and pressure. These numbers correspond to the plots of velocity and pressure described above.
Some additional output from the program is displayed on the control panel and some input panels. You can choose to display the lift or the lift coefficient by using the choice box on the control panel. The value is displayed in the output box to the right of the choice box. Lift may be expressed in either English or metric units (pounds or Newtons). On the Flight Test input panel is a group of output boxes that give the atmospheric conditions of the air. The pressure, temperature, and density will change depending on the altitude and planetary inputs. On the Size input panel the geometric aspect ratio of the wing is displayed. The aspect ratio is defined to be the square of the span divided by the wing area and is included here for later calculations of wing drag.
The input variables are located on input panels that are displayed at the lower left. You can select the input to display by using the blue choice box on the control panel. You can choose to vary the Shape, the Size, or perform a Flight Test.
FoilSimU includes all of the options of the original FoilSim plus some additional input and output panels. These panels are made available so that you can study the details of the conformal mapping used in the Kutta-Joukowski analysis. In the analysis, flow around a cylinder is mapped into flow around an airfoil. Using the Input choice box on the control panel, you can display a generating plane input panel. The panel contains four input variables which control the size and location of the generating cylinder relative to the poles of the transformation, and the strength of the point vortex which is embedded in the airfoil. According to the Kutta condition of the analysis, the strength of the vortex is set to bring the aft stagnation point to the trailing edge. With this version of FoilSim, you can turn the Kutta condition off by using the analysis choice box on the control panel to study the effect. A graph of the flow in the generating cylinder plane is also available using the Plot Selection option of the Output choice box on the control panel.
The Learning Technologies Project will continue to improve and update FoilSim II based on user input. Changes from previous versions of the program include: