Computational Aerodynamics Questions & Answers  
Question by Student 201427102
1.jpg  ./download/file.php?id=3370&sid=d24a104bdf8ad44becfe6dabc2a283b3  ./download/file.php?id=3370&t=1&sid=d24a104bdf8ad44becfe6dabc2a283b3
for middle block, you use "BLOCK(    ,GG,   );"
2.jpg  ./download/file.php?id=3368&sid=d24a104bdf8ad44becfe6dabc2a283b3  ./download/file.php?id=3368&t=1&sid=d24a104bdf8ad44becfe6dabc2a283b3
for middle block, you use "JOINT(    ,GG,   );"
3.jpg  ./download/file.php?id=3369&sid=d24a104bdf8ad44becfe6dabc2a283b3  ./download/file.php?id=3369&t=1&sid=d24a104bdf8ad44becfe6dabc2a283b3
However, this case, for middle block, you use "JOINT(   ,EE,   );" Why I shoud use 'EE' rather than 'GG'??
03.27.17
First, the command is Join(), not Joint(), and is case sensitive. So, if you use JOIN or join it will not work: it has to be spelled Join. For the third mesh, you can not use Join(is,js,ie,je,j,GG..) because the GG segment grabs the spacing from the mesh along the j coordinate. So in this case, he will set the first grid spacing (between j=js and j=js+1) to the distance between the point (i,js-1) and the point (i,js). However, there is no point (i,js-1) because it is outside of the domain. Good question: 2 points bonus boost.
Question by Student 201227147
Professor, I have a question about the today's class. During the class, to set $js1$ which is the midpoint of $js$ and $je$, you wrote as follow: $$js1 = round(0.5*(je-js));$$ but if I set $js = 40$ and $je = 100$, $js1$ becomes 30 which is not located between $js$ and $je$. Similarly, you wrote $is_1$ as follow: $$is1 = round(((ie-is)-0.7*(ie-is))/2);$$ but if I set $is = 40$ and $ie = 100$, $is1$ becomes 9 which is also not located between $is$ and $ie$. Could you tell me what I'm thinking wrong?
03.28.17
You are not wrong.. Rather, I forgot to include some term. It should have been written: $$ \rm js1=round(0.5 * (je-js))+js; $$ and $$ \rm is1=round(0.3*(ie-is)/2)+is; $$ Good observation: 2 points bonus boost.
Question by Student 201227106
Professor, I think Assignment 3 has a problem. In question #2, Q is consist of omega*U, but I think Q is consist of omega*capital gama*U.
03.29.17
That's right: I fixed it. I'll give you 1 point bonus boost because your typesetting was hard to read.
Question by Student 201227141
Professor, Q3 in Assignment3 is finding $G_η$ at nodes. Althogh Eqation has Ω, it did not need to calculate. Then is it not problem whatever Ω's value is?
03.30.17
Yes, absolutely, you don't need to calculate $\Omega$ in this case. But if you choose not to calculate it, you have to explain clearly how $\Omega$ cancels out. Once $\Omega$ disappears from the terms, then there is of course no need to calculate it. Good observation: 2 points bonus.
Question by Student 201427102
naninani.PNG  ./download/file.php?id=3378&sid=d24a104bdf8ad44becfe6dabc2a283b3  ./download/file.php?id=3378&t=1&sid=d24a104bdf8ad44becfe6dabc2a283b3
after write "paraview post.grid", that message appear. How can I solve this problem?
“ERROR: In /build/paraview-arsa8T/paraview-5.0.1+dfsg1/ParaViewCore/ServerImplementation/Core/vtkSIProxy.cxx, line 310 vtkSISourceProxy (0x3b3f430): Failed to create vtkXdmfReader. Aborting for debugging purposes. Aborted (core dumped)”
03.31.17
Well, the file name should end with .vtk in order to be read in paraview.. I'll give you 1 point bonus boost.
Question by Student 201427564
.png  ./download/file.php?id=3383&sid=d24a104bdf8ad44becfe6dabc2a283b3  ./download/file.php?id=3383&t=1&sid=d24a104bdf8ad44becfe6dabc2a283b3
Professor, I have a question about last Tuesday class. In attached figure, You coded is=1, js=1 in line 8. But you put zero in command 'Corners' in line 27. It works well but I can not understand. Please explain the reason. Also, I think is3 should be declared before is2. Because is2 contains is3. Am I right?
04.01.17
The first two zeros in the Corners() command are for the $x$ and $y$ positions of the lower-left corner. The next two values are for the $x$ and $y$ positions of the upper-right corner. For the second question, yes, if is2 depends on is3, then you should initialize is3 before initializing is2. Two points bonus boost.
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