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

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

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?

I think you want to run two NEK instances which are coupled through an interface boundary condition, right?

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
>> 
>> _______________________________________________
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> -- 
> 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
> 
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