Dear Geordie, Thank you for your quick response, and it is really appreciated very much.
I did get to know those free software like GetDP and FreeFem++ during my search on mesh generation software, but I don't have a chance to explore them in detail. As mentioned early in my email, I am new/beginner in using the Gmsh or the C++, therefore, I cannot fully understand a lot of things mentioned in your email. You may find that my questions are very simple but I do need experienced people like you to advise or direct me to the right direction and tell me a bit more detailed on how I should deal with the problems. Yes, I am now able to view/read the nodes and elements value from my (.msh) file by using Notepad, and it is interesting to see all the value for nodes and the value for elements. Can I ask, by having this nodes and elements value, how am I supposed to make use of these values and allow the C++ code to read/coordinate these values? I have looked into the "utils/api_demos/mainSimple.cpp" program; can you please advise what this code is about? Is this code used for generating the mesh or generating the geometry? Another thing is, the mesh that I generated in (.msh) file of my 110404_model is an unstructured mesh, it should contains of 1026 Nodes on lines, 3006 Nodes on surfaces and 8008 Triangles. I am not sure why you see it as a structured mesh? Is it because the setting in Tools>Options>Mesh> General on Gmsh software different? Thank you for your help and look forward to hearing from you. Kind regards, Anthony Chong Research Fellow Department of Architecture and Built Environment Faculty of Engineering The University of Nottingham University Park Nottingham NG7 2RD, UK Tel: +44 (0)115 846 7132 [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Geordie McBain Sent: 05 April 2011 00:51 To: Anthony Chong Cc: [email protected] Subject: Re: [Gmsh] Mesh Code/Source for Heat Transfer > I am currently working on a project which is about the ground-coupled heat exchanger model. The model is used to simulate the heat transfer process of surrounding soil of the circular pipe, where heat is extracted or generated within the circular pipe. I will need to write a code (in C++) to simulate the transient heat transfer for the pipe (i.e. circular cylindrical) within soil (i.e. rectangular domain model). While you can write a code in C++ for this, you don't really need to; several serviceable C++ codes for the solving the heat equation, are freely available. Try GetDP, FreeFem++, OpenFOAM, or libMesh, for example; the first of these enjoys close links with Gmsh. > (1) After the mesh has been generated, can I read or view the mesh code/source coordinate data? Yes. The 110404_Model in msh.msh file you generated and included in the zip-archive is in an ASCII format, so you can read it yourself in a text-editor (e.g. Emacs or vi) or parse it fairly easily in any programming language. The format is simple and is described in the manual: http://geuz.org/gmsh/doc/texinfo/gmsh.html#MSH-ASCII-file-format > (2) Once I have got the mesh code/source coordinate data, how would I be able to transfer or link these data into my C++ program? If you do decide to go this way, you'll find an example of reading a Gmsh geometry .geo file, meshing it, and processing the resulting mesh in utils/api_demos/mainSimple.cpp in the Gmsh source distribution. > As mentioned, I will be using transient heat transfer equation in cylindrical polar coordinate system to determine the heat transfer effect of the circular pipe. The equation shows as below: You may well be better off working with the equation in the Cartesian coordinate system, despite the circular pipe. It's much easier to generate an unstructured mesh than a structured one which respects the coordinate system, and once you've done that, I think you've lost whatever advantages a special coordinate system might have. > Another thing is that, I have downloaded the Gmsh 2.5.0 Source Code from your website, and I am wondering how I shall read this source code, and whether I can link/use one of the codes into my simulation model (or mesh model) from the Source Code? You probably don't need to read the Gmsh source code, except out of curiosity or if you find later you need to fix or bug or extend the program, but Gmsh is already in a sufficiently mature state that you shouldn't need to for solving the heat equation in a reasonably well-defined geometry. But don't let me discourage you: see the other examples in utils/api_demos. This message and any attachment are intended solely for the addressee and may contain confidential information. If you have received this message in error, please send it back to me, and immediately delete it. Please do not use, copy or disclose the information contained in this message or in any attachment. Any views or opinions expressed by the author of this email do not necessarily reflect the views of the University of Nottingham. 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