is a beta 1.3a version of the ShockModeler 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 email@example.com.
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
There are several different versions of ShockModeler which
require different levels of experience with the package,
knowledge of compressible flows, and computer technology.
This web page contains the on-line version of the program.
It includes an on-line user's manual which describes the
various options available in the program and includes hyperlinks to
pages in the
NASA's Guide to Hypersonics
Beginner's Guide to Compressible Flow
describing the math and science of shock waves.
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:
With the downloaded version, you can run the program off-line and do not
have to be connected to the Internet.
There is a special
version of ShockModeler
that deals only with the single oblique or normal shock
formed by a wedge or cone.
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
buttons on the blue bar at the top of the program.
The current 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
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 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.
At any time, to return to the original default conditions,
click the white and red Reset button on the blue bar.
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
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
program screen is divided into three main parts:
top of the screen is a graphic of the wedges and shock waves that you are
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 wedges are numbered with black numerals
that correspond to the wedge angle numbers on the input panel.
The red wedge is wedge #1 and the green wedge is wedge #2.
Oblique shock waves are drawn as blue lines with a numeral near the
middle of the line. (For some highly inclined lines, it may be difficult to
read the shock number.) Normal shocks are colored magenta, and the beginning
and end of an expansion fan are drawn as black lines. For shock-on-shock
interactions, slip lines (or shear layers) are often generated. The static
constant across a slip line although the
Mach number changes.
Slip lines are drawn in black on the graphic.
You can Zoom in for a closer look at the graphic by using the
slider bar at the left. You can also move the graphic by clicking in the
window, holding down on the left mouse button and dragging the graphic
to a desired location. If you lose the graphic, you can bring it back
to its default position and size by clicking on the "Find" button on
the blue bar. The "Reset" button will also set the input conditions
to their default values.
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
wedges. Again, angle #1 sets the size of the red wedge, angle #2 sets the
green wedge for the double wedge and opposed wedge problems.
For the multiple wedge problems you must also specify the distance between
the wedges. This input is given by the Spacing variable. The
gamma variable is the ratio of
of the gas.
output from the program is displayed at the lower right.
The output is displayed by Zones, with each zone being the
flow domain downstream of a shock wave or expansion fan. The shocks
are numbered on the graphic with a blue numeral; the zone number
corresponds to the shock number.
You select which zone to display by using the white and red
zone choice button.
The output variables on the left
are referenced to flow upstream of the shock, while the
variables on the right are referenced to free stream conditions.
below the Zone button is the
of the flow in the specified zone, Mach-up to the
right of the zone button is the Mach number upstream of the shock wave.
Angle is the wedge angle that is generating the shock
in the selected zone, while Turning is the total amount that
the flow has been turned relative to free stream.
the shock angle. The static and total
are listed, followed by the
ratios. These values are calculated using the
or normal shock relations.
Educations Program Office will continue to improve and update
ShockModeler based on user input. Changes from previous versions of
the program include:
On 18 Feb
11 version 1.3a was released. This version of the program has imposed some
limits on the downtream Mach number for a centered expansion fan. Any Mach number
greater than 50 is reset to M=50. This avoids the appearance of pressure ratios
equal to zero. Textbooks and NACA 1135 put similar artificial limits on the
downstream Mach number and Prandtl-Meyer angle. Prandtl-Meyer maximum value is
[ pi/2 * (sqrt((gamma+1)/(gamma-1))-1) ] which gives an infinite Mach number.
On 14 Apr
06 version 1.2a was released. The name and layout of the program was
changed and the input manual was developed for ShockModeler.
This version supports NASA's Guide to Hypersonics
and will be used in the high speed inlet simulator.
On 20 Dec
05 version 1.1b was released. This version was developed
for the NASA portal and was called Multiple Shock Simulation.
On 22 June
05 version 1.1a was released. This version was developed
for the Beginner's Guide to Rockets and moved onto the ESMD
03 version 1.0a was developed. This version was created to support
the Beginner's Guide to Compressible Flow and solved the expansion
fan, crossed shock, and reflected shock problems.