is a beta 1.6g version of the SuperSim simulation program, and you are invited
to participate in the beta testing. This simulation is provided by the
Supersonics Project within NASA's Fundamental Aero Program. The simulation is
continually being debugged, updated, and additional problems will be included based
on user inputs and requirements from the project. If you find errors in the program or
would like to suggest improvements, please send an e-mail to firstname.lastname@example.org.
Due to IT
security concerns, many users are currently experiencing problems running NASA Glenn
educational applets. There are
security settings that you can adjust that may correct
With this software you can investigate several fundamental problems
that occur in
The simulator models supersonic flow past a
the supersonic flow that leaves a jet
and the internal design of high speed nozzles using the
method of characteristics.
Depending on the Mach number and the size of object,
normal shocks are formed at the leading edge of the object.
You can study this flow by
interactively changing the values of different input parameters.
There are several different software packages available at the
Beginner's Guide to Compressible Flow
to study supersonic flow problems.
This page includes an on-line user's manual which describes the
various options available in the program and includes hyperlinks to
other pages describing the math and science details.
This software is intended for college students or professionals
working with compressible flows.
More experienced users can select a
version of the program which does not include
these instructions and loads faster on your computer.
There are other special programs available at this site
which solve for flow past a supersonic
cone and a supersonic
There is also a special program to solve for
multiple shock waves
with shock reflections and intersections. The multiple shock program
also solves for Prandtl-Meyer
expansions which occur when the flow is
turned into an expanding region.
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
If you experience difficulties when using the sliders to change variables,
simply click away from the slider and then back to it.
the arrows on the end of the sliders disappear, click in the areas
where the left and right arrow images should appear, and they
This program is designed to be interactive, so you have to work with the program.
You choose a particular flow problem by clicking on the white
choice button near the middle of the program, below the graphic.
You can currently (Apr, 2014) choose
Preliminary 2D nozzle design using method of characteristics (MOC).
Preliminary axisymmetric nozzle design using MOC.
You make a selection by clicking the mouse in the choice box, and high-lighting
your choice in the drop-down menu.
The value of flow 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.
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.
A black box with green, cyan, or
yellow numbers is an output box and the value is computed by the program.
There are some choices which you must make regarding the display
of computed results by using a buttons.
Click on the button to make your selection.
A yellow button indicates the current selection.
program screen is divided into three main parts:
top of the screen is a graphic of the problem that you are studying.
lower left side of the screen is the input panel.
lower right side of the screen are the results of
On the graphics display, supersonic flow is from left to right.
The geometry is shown in red.
Oblique shock waves are drawn as blue lines.
Normal shocks are colored magenta. Expansion fans are shown
in red or black. For the conical flow problem, flow
variables are constant along rays of a cone starting at the leading edge.
The rays are shown in blue. You can choose to display the values of the flow variables
for a particular ray on the output panel. The ray that you choose is shown
in red on the graphics panel.
Streamlines from upstream and flowing through the shock waves are shown in black.
If the MOC rays look chaotic, you have a grid resolution problem. Increasing the number of
rays on the input panel will normally solve this problem.
input to the program is entered at the lower left.
You can specify the free stream
Mach number by using either the
input box or the slider. You can also specify the angles for the
wedge or cone. The
gamma variable is the ratio of
of the gas.
Additional input depends on the particular problem being simulated.
output from the program is displayed at the lower right.
The output for the conical flow is displayed by Rays,
with each ray beginning at the tip of the cone.
You select which ray to display by using the white and blue
The output variables on the right
are referenced to flow upstream of the shock,
which are the free stream conditions.
below the Ray button is the
on the surface of the cone. Mach to the
right of the zone button is the Mach number along the selcted ray.
Angle is the angle of the selected ray,
while Turning is the total amount that
the flow has been turned relative to free stream direction.
Shock Angle is
the angle of the shock wave. The static and total
are listed, followed by the
ratios. For the cone, these values are calculated using the
shock relations, followed by an
isentropic compression to the ray Mach number.
The ray Mach number is determined by the
For the wedge problem, flow variable values are determined by the
For the nozzle design problems, you can select to display the geometry
of the nozzle by using an input button.
Changes from previous versions of
the program include:
18 Apr 14 version 1.6g was released. This version of the program
corrected some major problems with the axisymmetric nozzle MOC calculation.
18 Nov 12 version 1.6f was released. This version of the program
involved some re-organization and resizing of the output variables and the elimination
of the planetary choice box for gamma.
24 Feb 12 version 1.6d was released. This version of the program was the first
release of the computer program. The version number reflects the fact that
the program was derived from Version 1.3 of the multiple shock simulation.
Versions 1.4-1.6c were
developmental versions of the program and not released to the public.