<div dir="ltr"><div>Hi Paul and Phillip,</div><div><br></div><div>Thanks for your replies. I will try to apply ALE to the entire domain and play with the BCs to try and get a result. I've already rejected the standard C-mesh for airfoils in favor of an unstructured circular domain because the C-mesh boundaries are not conducive to rotating the entire domain. If I'm unsuccessful with this approach I will try to apply a rotating inflow and add a Coriolis force to correct. In either case, if everything works out I would like to submit a very small example case to the Nek documentation to help others in their quest for a rotating domain. I'll post back here if I run into trouble, thanks again for your insight!<br></div><div><br></div><div>-Harry</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Aug 21, 2018 at 11:30 AM, <span dir="ltr"><<a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.gov</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div id="m_-1656188229304846507divtagdefaultwrapper" style="font-size:12pt;color:#000000;font-family:Calibri,Helvetica,sans-serif" dir="ltr">
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">Hi Harry,</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">One simple approach is to use ALE but to have the entire domain pitch,</p>
<p style="margin-top:0;margin-bottom:0">thus preserving your mesh structure.</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">That would properly account for all the accelerations in your non inertial</p>
<p style="margin-top:0;margin-bottom:0">domain. </p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">The slightly tricky part would be to determine what BCs you need. You</p>
<p style="margin-top:0;margin-bottom:0">need to be careful about changing the character of the BCs (e.g., from inflow</p>
<p style="margin-top:0;margin-bottom:0">to outflow) in the middle of a computation because that changes which quantities</p>
<p style="margin-top:0;margin-bottom:0">are prescribed and which are unknown. Perhaps one approach would be</p>
<p style="margin-top:0;margin-bottom:0">to have a circular domain with 3/4 of it Dirichlet and 1/4 being outflow (i.e.,</p>
<p style="margin-top:0;margin-bottom:0">Neumann for velocity).</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">hth,</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
<p style="margin-top:0;margin-bottom:0">Paul</p>
<p style="margin-top:0;margin-bottom:0"><br>
</p>
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<div id="m_-1656188229304846507divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Nek5000-users <<a href="mailto:nek5000-users-bounces@lists.mcs.anl.gov" target="_blank">nek5000-users-bounces@lists.<wbr>mcs.anl.gov</a>> on behalf of <a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.<wbr>gov</a> <<a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.<wbr>gov</a>><br>
<b>Sent:</b> Tuesday, August 21, 2018 9:43:56 AM<br>
<b>To:</b> <a href="mailto:nek5000-users@lists.mcs.anl.gov" target="_blank">nek5000-users@lists.mcs.anl.<wbr>gov</a><br>
<b>Subject:</b> [Nek5000-users] Rotating computational domain</font>
<div> </div>
</div><div><div class="h5">
<div>
<div dir="ltr">
<div>Hello Neks,<br>
<br>
</div>
<div>I am an undergraduate student new to Nek and I am working on a simulation studying dynamic stall in a dynamically pitching airfoil. I want to do a pitch and hold simulation at low Reynold's number (Re = 12000) where I rotate the entire computational domain
up to about 50 degrees AOA and then hold at 50 degrees, with steady inflow ux = 1. I would like to rotate the domain about the z axis, which passes through the quarter chord location of the airfoil profile (modified NACA 0012).<br>
</div>
<div><br>
</div>
<div>Because of the steep AOA, I would like to stay away from pitching the airfoil within the stationary domain with ALE to avoid too much mesh deformation. To this end, I have been scouring documentation to try and find a method of applying a rotational mesh
velocity to the entire domain about the z axis while keeping the flow within the domain at ux = 1. I am feeling very stuck. Others have suggested applying a Coriolis force to the flow, but I don't really see how this would simulate rotation of the entire
domain. It seems to me that simulation of a Coriolis force would be acceptable to correct the flow field to always be ux = 1 inside a rotating domain, but I don't see how that would apply a mesh velocity anywhere.</div>
<div><br>
</div>
<div>Are there any examples where an entire computational domain is rotated that I can look at, or has anybody done similar work who can point me in the right direction?</div>
<div><br>
</div>
<div>Regards,</div>
<div>-Harry</div>
</div>
</div>
</div></div></div>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">Harry E. Werner IV<div>Secretary</div><div>Clarkson University SCUBA Club</div><div><u>Cell:</u> (716) 570-4023</div></div></div>
</div>