I need a physics simulator program.?

Question

What program does NASA (and everybody else that does things that involves air) use to simulate atmosphere? Is it a normal, but expensive program, or does everybody just make their own?

Answer 1

There is no one program that simulates all of physics.

Programs or codes are written with a very specific purpose in mind.

For instance, if you want to know how light is absorbed and scattered in the atmosphere (like for a remote sensing application), then you'd use something like MODTRAN.  See the wikipedia entry for atmospheric radiative transfer models.

If you were after how the atmomsphere works on a global scale (climate change, weather forcasting, etc), then you'd be after some sort of Global Climate Model -- see the link.

You you wanted to understand the forces on an airplane for example, turbulence, drag and such, then you are interested in the broad category of Computational fluid dynamics, or CFD.  See the link I've provided for a good list of codes and software for that application.

There are probably many other specialized models of different aspects of the atmosphere ... so you need to figure out what you need first!

In general, code libraries that were started 30 years ago are written in Fortran -- people don't want to go through the effort to rewrite these in a more modern language.  More recently developed code will be in C or C++ usually.  Again, these are just libraries of code, that you have to stitch together yourself by writing your own program in the appropriate language.   There are also specific pre-built applications with GUIs, etc that various companies sell.  Also general numeric computation programs, like Matlab, are sort of a middle ground -- general purpose user interface, that can be linked in to C or FORTRAN libraries, etc