General problems

What is the meaning of the name CrysMAS?

CrysMAS stands for Crystal and Finite-Volume technique on Unstructured meshes.

What kind of support can I get from CGL?

Each CrysMAS license includes a one week training at CGL. This is usually enough to get familiar with all features of the program and to define a basic model of your furnace set-up. Nevertheless, if problems occur you can contact our hotline at CGL_support@iisb.fraunhofer.de. In order to get the best support you have to precisely define your problem. In some cases it might be necessary to send the *.crys file of your furnace model. Of course, all your data will be treated as confidential.

What kind of computer do I need for the computations?

CrysMAS runs on a standard PC. As the simulations require a big amount of computational resources you should use the fastest CPU you can get. The memory is normally not the bottleneck. Please note also, that you may create a huge amount of data. A rather big hard disc drive is therefore recommended as well.

Do you recommend the Windows or the Linux version of CrysMAS?

Both CrysMAS versions are completely identical - the choice is up to you.

I am not familiar with numerical techniques. Can you provide me some literature?

There are many good books on this topic available. Although it is already a rather old book, beginners should have a look in the book of S.V. Patankar: "Numerical heat transfer and fluid flow", Hemisphere Publishing Corporation, 1980. The book presents in a very descriptive way the principles of a finite-difference/finite-volume discretization, different time-discretization schemes and the sources for numerical instabilities. It is interesting to note, that even today the book is regularly cited in the scientific literature on this topic. Another interesting book is from J.H. Ferziger and M. Peric: "Computational methods for fluid dynamics", Springer, 1999. This book is a bit more mathematical than the previous one. In addition to the previous topics, the reader finds some nice sections on the solution of linear equation systems and the modeling of turbulent flows. Furthermore, every phd-thesis created at the numeric group of CGL usually contains a chapter on numerical issues as well.

My CrysMAS license is expired? How can I extend it?

You should either contact the user support of CGL at CGL_support@iisb.fraunhofer.de, or the head of our group Jochen.Friedrich@iisb.fraunhofer.de.

Is there an ideal way to perform numerical simulations?

Unfortunately not. Nevertheless, there are some basic principles which you should consider when performing a numerical simulation. First of all never forget that a lot of complicated numerics is going on in the background. You should stepwise increase the complexity of the model. First make sure that you are able to make a normal forward simulation of the temperature field. Then include one or more control points. In a next step you could start to consider convection as well. In order not to forget any parameter setting, you should always follow the CrysMAS menu structure, which is from left to right (preparation/simulation/analysis) and from the top to the bottom in each menu. When you perform your computations you will soon recognize that you create a lot of files with even more data. We therefore recommend to use the File Info dialogue, where you can add a short description of the performed computation.

How can I learn details on the implemented physical models in CrysMAS?

Some information is already provided in this document. Additional information can be found in phd-thesis or diploma thesis, created at CGL (Bibliography ). The best information on the numerical treatment of the energy equation and the principle of the inverse simulation can be found in M.R.H. Kurz: "Development of CrysVUn++, a software system for numerical modeling and control of industrial crystal growth processes", Tech. Fac. Erlangen-Nuremberg, 1998.

Why is the Context Sensitive Help not activated in CrysMAS?

The help system is based on the on-line (HTML) version of CrysMAS User Manual. If you get the software by e-mail, the installation kit does not contain the user manual. You have to download it from CGL home page and install it into CrysMAS Doc subdirectory.

If you have installed the user manual files and the help is still not available, you should check the program configuration, see Activating the Context Sensitive Help section.

Under Linux, menu texts are looking bad (no antialiasing)

try setting this environment variable: QT_X11_NO_FONTCONFIG=1