[CeesH]

I'm not saying that. I say both are an approximation. To decide whether the approximation is reasonable is up to you. To be a CFD researcher does not mean you are able to push the right buttons in a software package. I can teach any humanities student to do that in a day. It means you are able to evaluate the results, test the physical meaning, judge their errors and draw conclusions about that. If you can do that, you can determine if the answer you found is sufficiently correct, and why it may or may not be.

[Falcon35]

Originally Posted by CeesH

I'm not saying that. I say both are an approximation. To decide whether the approximation is reasonable is up to you. To be a CFD researcher does not mean you are able to push the right buttons in a software package. I can teach any humanities student to do that in a day. It means you are able to evaluate the results, test the physical meaning, judge their errors and draw conclusions about that. If you can do that, you can determine if the answer you found is sufficiently correct, and why it may or may not be.

but that results aren't false ? may i give it as homework ?

[Falcon35]

Originally Posted by CeesH

I'm not saying that. I say both are an approximation. To decide whether the approximation is reasonable is up to you. To be a CFD researcher does not mean you are able to push the right buttons in a software package. I can teach any humanities student to do that in a day. It means you are able to evaluate the results, test the physical meaning, judge their errors and draw conclusions about that. If you can do that, you can determine if the answer you found is sufficiently correct, and why it may or may not be.

my other project didn't converged why ?

[CeesH]

That is also for you to decide. CFD will not give 'false' results, unless your solution does not converge. If it does (residuals go down, mean velocity becomes constant, etc) you will get results. The results are no better or worse than the assumptions you put in. Evaluate the validity and effects of those assumptions, and you will know the answer. I can't answer that question for you, because I don't know why you chose the models that you chose.

[Falcon35]

Originally Posted by CeesH

That is also for you to decide. CFD will not give 'false' results, unless your solution does not converge. If it does (residuals go down, mean velocity becomes constant, etc) you will get results. The results are no better or worse than the assumptions you put in. Evaluate the validity and effects of those assumptions, and you will know the answer. I can't answer that question for you, because I don't know why you chose the models that you chose.

my other project didn't converged why ?

[pakk]

Do you expect that we can magically connect to your computer, see which other simulation you are talking about, analyze it and find the mistake?

I am not capable of that.

[Falcon35]

Originally Posted by pakk

Do you expect that we can magically connect to your computer, see which other simulation you are talking about, analyze it and find the mistake?

I am not capable of that.

sorry but i mean why might it happen

[pakk]

There are so many possible reasons... I am not going to list them all. It is your simulation, so you should try out some things to find out why it diverged.

[Falcon35]

Originally Posted by pakk

There are so many possible reasons... I am not going to list them all. It is your simulation, so you should try out some things to find out why it diverged.

then can you tell me which layer i should use on a flat plate length of 5 m ? And which sizing value should i use ?

[pakk]

No. I don't know that.

[CeesH]

Look, we can't do your homework for you. That includes that I'm not going to re-run your simulation as you requested in your private message. It's your homework, not ours. We can look at technical questions you have if you don't know how to do something, give some advice, but that's where it ends. You are the one that has to learn in the end, so you are the one that has to make assumptions, check their validity, and comment on your solution. Doing your work for you is not just a waste of our time, it is even more a waste of yours.

[pakk]

I completely agree. The goal of the homework was probably not to find strangers on the internet who would do the work for you.

To be clear: I have no problem with people asking homework questions on this forum. But there is a certain limit.

Would you show your teacher that you asked these questions here? That is, in my opinion, the crucial thing. If the questions are good, the teacher would think "My student asked good questions, it is good that he found this method to gain knowledge. I can see that he learned something.". And in that case, it would be no problem to show it to your teacher, it would even be good to do that, as he may value you more. But if the questions are bad, the teacher would think: "My student did not think himself, but let the other people do all the thinking. I can see that he learned nothing, and that the homework he did is not really his work.". In that case, you should not show it to your teacher.