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Potto-GDC (Gas Dynamics Calculator)

What GDC is capable of?
This program is about 10,000 lines of code (only the engine, not including the interface) and can do more than its creator can imagine. This program is the most extensive known to do 1D and some 2D gas dynamics calculations.

We continue to discover new capabilities and new challenges with this program.

It can do isentropic, isothermal, Fanno (choked and chokeless), and Rayleigh flow. As this program uses the exact calculations, it can find the maximum oblique shock easily. But more than that it can provide the three solutions of the oblique shock. It can calculate even the “naughty professor” such as for given mass flow rate per area with stagnation temperature and static pressure. GDC also can generate the oblique shock figure for arbitrary specific heat. What other program can do that? None.

The program also provides the results in plain text or LaTeX. It provides for single value or for a whole range of value (tables).

No less important, it is open source/content: You can use it as a building block or library.
Latest Announcements
On January 25th, 2008, the latest version 0.5.1 was released. release notes, ChangeLog, Download The new version also calculates shock dynamics suddenly close, suddenly open and partially close valve.

On top of that, GDC calculates the speed of shock in-front of piston (see the equations in the book).

In addition, the new version also calculates the shock location in Fanno flow with the iterations information.
more announcements.
Who is using GDC?
We don‘t really know the numbers, given the open nature of the GDC program. What we do know is that the GDC is very popular on Freshmeat.net. We also know that some of the program‘s users are people in NASA, in universities, and in industry. Some request consultations after using GDC. The program is used in at least 90 countries. If you would like to add your name to the user list, send email to barmeir at gmail.com.
History of Potto-GDC
Gas Dynamic Calculator, (Potto-GDC) was created to generate various tables for the book. In 2004, this calculator was given to several individuals who found Potto-GDC to be very useful. Initially, the Potto-GDC was many small programs for specific tasks. For example, the stagnation table was one such program. Later, the code became a new program to find the root of something between the values of the tables, e.g., finding parameters for a given 4fL/D. At that stage, the program changed to contain a primitive interface to provide parameters to carry out the proper calculations.

At the time, every flow model was a different program. When it become cumbersome to handle several programs, the author utilized the object-oriented feature of C++ and assigned functions to the common tasks to a base class and the specific applications to the derived classes.

Later, a need to intermediate the stage of the tube flow model (the PipeFlow class) was created and new classes were created.

The graphical interface, created only after the engine was written, to provide a filter for the unfamiliar user. It also removed the need to recompile the code every time.

The latest addition to Potto-GDC is the utility to generate the oblique shock for arbitrary specific heat, k.
Minimum Requirements
The graphical interface and the “engine” for compressible flow calculator are in one package. The interface requires QT library. If you don't have QT library you still can use the calculations engine "here" (gdcT32.tar.gz) (6.2M compared to the version 0.4 is 565K) or the bzip2 file "here" (gdcT32.tar.bz2). There is also 64 bits versions. Note that if you use the engine, you need to create a very small input file with your data.
Screenshots let you see what Potto-GDC looks like while it's running, which means you get a feeling for what Potto-GDC is like without downloading the program.
Older Versions
We have retained the older versions for historical and other reasons (Version 0.4.3 and earlier).

About Potto Project

Potto Project NFP is Non-Profit organization created by Dr. Genick Bar-Meir and friends to build open sourcesoftware and open content textbooks for college students.Over 1,000,000 (million) Potto Project books have been downloaded from 175 different countries since 1995.

Potto Project is under open content licenses, which means that you will always have the freedom to use it, make copies, and improve it. You are encouraged to make use of these freedoms and share the textbooks and program with your family and friends!

Copyright (C) 2010, 2009, 2008, 2007, 2006, 2005, 2004, 2003 Dr. Genick Bar-Meir.
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or later or Potto license.
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