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<p>Yes. I would like to a rotational BCs(Twist bcs). <br>
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<p>Such a boundary is needed to reduce the computational domain.</p>
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<p>Thanks lot</p>
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<p>Best regards</p>
<p>Fengwen<br>
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<div class="x_PlainText">____________________________________________________<br>
Senior Researcher<br>
Department of Mechanical Engineering, DTU<br>
Nils Koppels Allé <br>
Building 404 <br>
2800 Kgs. Lyngby <br>
fwan@mek.dtu.dk</div>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> Lawrence Mitchell <wence@gmx.li><br>
<b>Sent:</b> Monday, October 29, 2018 1:17:34 PM<br>
<b>To:</b> Matt Knepley<br>
<b>Cc:</b> Fengwen Wang; PETSc; PETSc<br>
<b>Subject:</b> Re: [petsc-users] [petsc-maint] How to impose boundary conditions using DMDA</font>
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<br>
> On 29 Oct 2018, at 10:56, Matthew Knepley <knepley@gmail.com> wrote:<br>
> <br>
> You can certainly map the right edge to the top edge (its topologically a square again), but that<br>
> mapping is not smooth, and I do not know how you would make a global basis for the approximation space.<br>
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Yeah, I thought this was topologically just a cone, but that would have:<br>
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u(x=1) = -v(y=1)<br>
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and<br>
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v(x=1) = u(y=1) (note matching sign).<br>
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So if you wanted the v(x=1) = -u(y=1) there would be a twist somehow, and then a discontinuity in the mapping.<br>
<br>
Lawrence</div>
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