Discussion Forum

Hi

The best to start is really to read the doc (a few times, it's hard the first time, so do it in not too long sections)
Then go into the model library, print out the pdf files (v4.1) of the examples and follow them step by step. Start with simple examples in one physics, later start to couple two physics. Often starting in 2D before going to 3D. Note that 2D means in fact 3D physics but the third dimension is set typically to 1[m] so everything is expressed in "per meter"

Note that fluidics is already a tricky physical domain to simulate and require quite some prior knowledge, so often it's simpler to start with structual or thermal before going into CFD models. CFD models are also quickly heavy and require longer time to solve (if they converge)

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Good luck
Ivar

Hi

have you tried (for >=v4.1) to select the model library, find a simple example, print out the pdf file and go through it step by step and cross checking with the doc for each step, to reall understand the step by step apprch. It's tedious but very efficient. An even better approach is to get on one of the COMSOL courses (start with befginners level;) but these are not always available everywhere

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Good luck
Ivar

Hi mohamed, I'm a beginner & need flow simulation help too, so If I find something interesting while lerning comsol be sure i'll share U, Would U do the same? Good look & thank's

Hi

have you tried "File - Open Model Library" and looked for the examples there ? (the amount of stuff depends on the number of toolboxes you have a licence for)

For the rest I take my schoolboks and run through the examples, but first one need to really udnerstand what COMSOl is doing as well as its conventions, and that one can only learn by openin the library model, and select show pdf -> print and repeat the instructions therein

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Good luck
Ivar

Hi

not fully yet ;)

in my V4.1 (and I belive this was also so for the 4.0a, not sure, but anhow try to get hand on a 4.1 it's better documented and more stable) you will see two options for your library models: a pdf file generation (= your doc to read) and the model itself

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Good luck
Ivar

Hi Mohamed,

A good way to get started, as Ivar says, is to open the Model Library. Click on File, then "Open Model Library". Go to the CFD or Fluid Flow folder, and view a few models. For each model, there's an option "Open PDF", which will open a document describing the model.

If you want to know more, read the User's guide. Go to C:/Comsol41/doc/pdf/CFD and open the PDF.

Start simple.

It's good to keep your flow in the laminar region. Read on Wikipedia what the difference is between laminar and turbulent flow - keep the Reynold's number below ~1500.

Start in 2 dimensions; it's easier and will not put very large strains on your memory. Start by building a rectangle of 0.02m wide and 0.1 m long. Choose air as material. Make the left boundary an "inlet" condition at 0.1 m/s. Set the right boundary as "Outlet", pressure = 0 Pa. Set up your mesh fine and if possible, use boundary layers. If you're using Comsol v4.1, boundary layers will automatically be applied to ensure a reliable solution.

Good luck and have fun!