[Nek5000-users] Solving mesh Laplace equation (Re: Mesh morphing)

[nek5000-users at lists.mcs.anl.gov]

Dear Paul,

Thank you for this script!! It works very nicely to morph the mesh for the cylinder example.
I modified it to deform the mesh in both x- and y-direction, and made the cylinder into an ellipse (attached picture).
(If someone is interested in the code, I am happy to share it after tidy-up.)

Now I am experimenting with other meshes and blending functions.

Best regards,
Outi



> On 21 Feb 2015, at 00:34, nek5000-users at lists.mcs.anl.gov wrote:
> 
> 
> Hi Outi,
> 
> It's ok... it just means that the solver did not converge all the way... but the
> resulting field is nonetheless sufficiently smooth.
> 
> Paul
> 
> ________________________________________
> From: nek5000-users-bounces at lists.mcs.anl.gov [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov]
> Sent: Friday, February 20, 2015 5:11 PM
> To: nek5000-users at lists.mcs.anl.gov
> Subject: Re: [Nek5000-users] Solving mesh Laplace equation (Re: Mesh morphing)
> 
> Dear Paul,
> 
> Thank you very much, the idea seems exactly like what I would like to
> do. However, there is an error appearing in the Helmholtz solver. From
> logfile:
> 
>  call userchk
>   1.000000000000000E-006  p22            0           1
>      0   200 **ERROR**: Failed in HMHOLTZ: mshv   1.3206E-02
> 2.7147E+03   1.0000E-06
>  done :: userchk
> 
> Best regards,
> Outi
> 
> Quoting nek5000-users at lists.mcs.anl.gov:
> 
>> Dear Outi,
>> 
>> I have just added "ocyl2" to the ocyl example directory.
>> 
>> I think it addresses the question you raise.  Please advise and let
>> us know if you have any difficulties.
>> 
>> Paul
>> 
>> ________________________________________
>> From: nek5000-users-bounces at lists.mcs.anl.gov
>> [nek5000-users-bounces at lists.mcs.anl.gov] on behalf of
>> nek5000-users at lists.mcs.anl.gov [nek5000-users at lists.mcs.anl.gov]
>> Sent: Friday, February 20, 2015 11:39 AM
>> To: nek5000-users at lists.mcs.anl.gov
>> Subject: [Nek5000-users] Solving mesh Laplace equation (Re: Mesh morphing)
>> 
>> Dear Neks,
>> 
>> What I actually would like to accomplish is to solve the Laplace
>> equation for the mesh (with the boundary deformation as a BC). I saw
>> that this has been done already at least by Paul (a thread 2009) and
>> Matt (for smoothing of a wing mesh, with zero deformation).
>> Could any of you please give me a hint on how to solve the Laplace
>> equation for the mesh like this? Matt? Paul?
>> I would be very grateful.
>> 
>> Best regards,
>> Outi
>> 
>> Quoting Outi Tammisola <outi at mech.kth.se>:
>> 
>>> Dear Neks,
>>> 
>>> I thought this question might be of interest for someone else as
>>> well, so posting it here:
>>> 
>>> I have been looking at the oscillating cylinder example. I would
>>> like to do something similar, but instead of a prescribed boundary
>>> velocity, would like to prescribe a given displacement of one
>>> boundary, and morph my mesh smoothly everywhere to match this
>>> displacement. For example, if one were to describe a deformation of
>>> the cylinder rather than a velocity (but without altering the other
>>> boundaries and without scaling the mesh). This just needs to be done
>>> once, not at every time step.
>>> 
>>> Is there an easy way to do this? Can I arrive there somehow by minor
>>> modifications of the elasticity solver? What equation exactly is the
>>> elasticity solver solving at every time step?
>>> (When I outputted the files after every time step for the
>>> oscillating cylinder, the mesh deformation seemed to match the
>>> prescribed one only after 2 time steps. Is there a reason for this,
>>> or did I do something wrong?)
>>> 
>>> Best regards,
>>> Outi
>> 
>> 
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> 
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