[Nek5000-users] surface tension (Marangoni effect) driven flows

Fri Apr 2 07:30:52 CDT 2010

Yes, I think we can handle that using our new NEK-NEK capabilities!
The motivation for developing the NEK-NEK feature was slightly different though. The plan was to enable simulations with complex geometries and/or to have local high resolution zones without suffering from topological constraints.

No, I don't think we have a customer dealing with surface tension driven flows. But I could be wrong.
@Paul: you may want to comment on that?

-Stefan

On Apr 2, 2010, at 2:17 PM, nek5000-users at lists.mcs.anl.gov wrote:

> On Fri, 2010-04-02 at 14:02 +0200, nek5000-users at lists.mcs.anl.gov
> wrote:
>> Ok I see. It's hard to say if NEK can handle a problem like this.
>> Do you know what's needed on a solver level to tackle such a problem?
> 
> Hi Stefan,
> 
> My idea of the coupling would be to (at each time step):
> 
> 1)  solve the liquid using some guess for the velocity and temperature
> at the interface
> 
> 2)  define the tangential stress at and heat flux across the interface
> from using the values of the velocity and temperature in the liquid
> 
> 3)  using the tangential stress and heat flux from 2 as boundary
> conditions, solve for the gas (including at the interface).
> 
> 4) using the velocity and temperature at the interface found in 3, goto
> 1 and repeat till convergence.
> 
> 
>> 
>> I think you want to run two NEK instances which are coupled through an interface boundary condition, right?
> 
> Yes, that would be the goal. Each instance would have different fluid
> properties, and be connected to the other through the mentioned BCs at
> the interface.
> 
> Are you aware of any uses of Nek5000 to solve surface tension (Marangoni
> effect) driven flows?
> 
> Cheers,
> Frank
> 
>> 
>> Stefan
>> 
>> 
>> On Apr 2, 2010, at 1:49 PM, nek5000-users at lists.mcs.anl.gov wrote:
>> 
>>> On Fri, 2010-04-02 at 13:30 +0200, nek5000-users at lists.mcs.anl.gov
>>> wrote:
>>>> Hi Frank,
>>>> 
>>>> I guess you have to deal with a sharp interface in your two-phase flow problem.
>>>> The question is how do you resolve this interface having in mind (a) accuracy and (b) boundness (stability).
>>>> 
>>>> High-order methods are typically less robust to under-resolution and you need to play some tricks to get a bounded solution (e.g. using flux-limiters).
>>>> 
>>>> How do you plan to tackle this problem?
>>> 
>>> Hello Stefan,
>>> 
>>> The interface does not need to be resolved, it is known.  The situation
>>> is the following.  There is a liquid drop surrounded by gas.  The
>>> surface tension of the liquid is high enough that the shape of the
>>> liquid (i.e., the interface) is not affected by the flow in the liquid
>>> or in the gas.  Therefore the shape of the interface is determined
>>> entirely by the contact angle and gravity.  However, the gas "sees" the
>>> liquid and vice versa, thanks to the continuity of velocity,
>>> temperature, tangential stress and heat flux across the interface.  It
>>> is worth noting that, taking an incompressible gas and liquid, the
>>> pressure level of the gas is not coupled to that of the liquid.  So the
>>> problem can be thought of as two separate simulations which have a
>>> boundary across which they share the above boundary conditions.  So not
>>> a true two-phase flow.
>>> 
>>> Cheers,
>>> Frank
>>> 
>>>> 
>>>> 
>>>> -Stefan
>>>> 
>>>> 
>>>> On Apr 2, 2010, at 1:14 PM, nek5000-users at lists.mcs.anl.gov wrote:
>>>> 
>>>>> Hello all,
>>>>> 
>>>>> I am interested in the opinion of users and developers as to whether it
>>>>> is practical to use Nek5000 for a "two-phase" flow problem.  I write
>>>>> "two-phase" since the interface between the two fluids is fixed, with
>>>>> only the shear stress and tangential velocity matched there (normal
>>>>> velocity being zero) and temperature and normal heat flux.  In addition,
>>>>> on the liquid side of the interface there is a shear stress proportional
>>>>> to the temperature gradient along the interface (Marangoni effect).  
>>>>> 
>>>>> Also, am I correct in understanding that all components of velocity are
>>>>> stored at the same location (the Gauss–Lobatto–Legendre points), while
>>>>> the pressure is located at the Gauss–Legendre points?  This being in
>>>>> contrast to a MAC type staggered grid, where each velocity component
>>>>> resides at different spatial locations.
>>>>> 
>>>>> Cheers,
>>>>> Frank
>>>>> 
>>>>> -- 
>>>>> Frank Herbert Muldoon, Ph.D. Mechanical Engineering
>>>>> Technische Universität Wien (Technical University of Vienna)
>>>>> Inst. f. Strömungsmechanik und Wärmeübertragung (Institute of Fluid
>>>>> Mechanics and Heat Transfer)
>>>>> Resselgasse 3
>>>>> 1040 Wien
>>>>> Tel: +4315880132232
>>>>> Fax: +4315880132299 
>>>>> Cell:+436765203470
>>>>> fmuldoo (skype)
>>>>> http://tetra.fluid.tuwien.ac.at/fmuldoo/public_html/webpage/frank-muldoon.html
>>>>> 
>>>>> _______________________________________________
>>>>> Nek5000-users mailing list
>>>>> Nek5000-users at lists.mcs.anl.gov
>>>>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>>>> 
>>>> _______________________________________________
>>>> Nek5000-users mailing list
>>>> Nek5000-users at lists.mcs.anl.gov
>>>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>>> -- 
>>> Frank Herbert Muldoon, Ph.D. Mechanical Engineering
>>> Technische Universität Wien (Technical University of Vienna)
>>> Inst. f. Strömungsmechanik und Wärmeübertragung (Institute of Fluid
>>> Mechanics and Heat Transfer)
>>> Resselgasse 3
>>> 1040 Wien
>>> Tel: +4315880132232
>>> Fax: +4315880132299 
>>> Cell:+436765203470
>>> fmuldoo (skype)
>>> http://tetra.fluid.tuwien.ac.at/fmuldoo/public_html/webpage/frank-muldoon.html
>>> 
>>> _______________________________________________
>>> Nek5000-users mailing list
>>> Nek5000-users at lists.mcs.anl.gov
>>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>> 
>> _______________________________________________
>> Nek5000-users mailing list
>> Nek5000-users at lists.mcs.anl.gov
>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
> -- 
> Frank Herbert Muldoon, Ph.D. Mechanical Engineering
> Technische Universität Wien (Technical University of Vienna)
> Inst. f. Strömungsmechanik und Wärmeübertragung (Institute of Fluid
> Mechanics and Heat Transfer)
> Resselgasse 3
> 1040 Wien
> Tel: +4315880132232
> Fax: +4315880132299 
> Cell:+436765203470
> fmuldoo (skype)
> http://tetra.fluid.tuwien.ac.at/fmuldoo/public_html/webpage/frank-muldoon.html
> 
> _______________________________________________
> Nek5000-users mailing list
> Nek5000-users at lists.mcs.anl.gov
> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users