[Nek5000-users] Pipe with expansion
nek5000-users at lists.mcs.anl.gov
nek5000-users at lists.mcs.anl.gov
Tue Jan 21 10:24:06 CST 2014
Hi Paul,
I checked the set_obj subroutine and implemented one in my .USR file.
The code seem to run without any errors but I don't find where these
variables are getting stored.
I use VisIT to visualize my output, even there was no change in it.
do I have to define my own output file and write the variables out ?
Thanks,
Kamal.
On 20/01/2014 21:52, nek5000-users at lists.mcs.anl.gov wrote:
>
> Hi Kamal,
>
> You'll need to compute your own tke by manipulating the
> velocity fields.
>
> You can get running averages of the requisite quantities
> via calls to "avg_all" which is found in navier5.f
>
> You can compute shear stress on the wall simply by computing
> the drag on the wall, which can be done via a call to torque_calc(),
> also found in navier5.f
>
> If you cd to /examples and type:
>
> grep torq */*.usr
>
> you'll find many examples of calls to torque_calc. You simply
> need to prescribe the surfaces on which shear is to be integrated.
>
> I typically write a routine "set_obj" to identify such surfaces
> on the first call to usrchk.
>
> grep set_obj */*.usr
>
> will show similar examples.
>
> I would recommend trying this for laminar Poiseiulle flow in
> a very simple channel just to check that your calls are properly
> set.
>
> Best,
>
> Paul
>
>
> On Mon, 20 Jan 2014, nek5000-users at lists.mcs.anl.gov wrote:
>
>> Hi Paul,
>>
>> Thanks and that helped.
>>
>> Where can I find the variables like Turbulent KE , shear stress on
>> the wall. ?
>>
>> Do i have to activate some parameters for calculating them ?
>>
>> If I had to plot them.
>>
>> Thanks,
>> Kamal
>>
>>
>> On Jan 20, 2014, at 5:41 AM, nek5000-users at lists.mcs.anl.gov wrote:
>>
>>>
>>> Kamal,
>>>
>>> Looks good.
>>>
>>> I'm guessing that one further refinement would be:
>>>
>>> if (z.gt.z0) scale = 1 + (smax-1)*(z-z0)/(z1-z0)
>>> if (z.gt.z1) scale = smax
>>>
>>> which would yield
>>>
>>> scale = 1 when z=z0
>>> scale = smax when z >= z1
>>>
>>> Paul
>>>
>>>
>>>
>>> On Sun, 19 Jan 2014, nek5000-users at lists.mcs.anl.gov wrote:
>>>
>>>> Hi paul,
>>>>
>>>> The code works fine, but there should be a small change thats has
>>>> to be done
>>>>
>>>>
>>>> if (z.gt.z0) scale = 1 + (z /(z1-z0 )))
>>>> if (z.gt.z1) scale = smax
>>>>
>>>> This creates a perfect diverging pipe.
>>>>
>>>> Thanks for the help paul.
>>>>
>>>> Kamal
>>>>
>>>> On Jan 20, 2014, at 12:09 AM, nek5000-users at lists.mcs.anl.gov wrote:
>>>>
>>>>> Hi paul,
>>>>>
>>>>> If I am not wrong,
>>>>> I make a mesh with three straight pipes( inlet, divergent, outlet
>>>>> ) connected together via n2to3 so that I know the element
>>>>> connectivity places of the divergent section (z0,z1) and use the
>>>>> section what you gave
>>>>>
>>>>> Thank you for the code
>>>>>
>>>>> Kamal
>>>>>
>>>>> On Jan 19, 2014, at 8:45 PM, nek5000-users at lists.mcs.anl.gov wrote:
>>>>>
>>>>>>
>>>>>> Kamal,
>>>>>>
>>>>>> I would do the following in usrdat2():
>>>>>>
>>>>>> n=nx1*ny1*nz1*nelt
>>>>>>
>>>>>> do i=1,n
>>>>>> x=xm1(i,1,1,1)
>>>>>> y=ym1(i,1,1,1)
>>>>>> z=ym1(i,1,1,1)
>>>>>> scale = 1.
>>>>>> if (z.gt.z0) scale = smax*(z-z0/(z1-z0)
>>>>>> if (z.gt.z1) scale = smax
>>>>>> xm1(i,1,1,1) = scale*x
>>>>>> ym1(i,1,1,1) = scale*y
>>>>>> enddo
>>>>>>
>>>>>> Paul
>>>>>>
>>>>>> Make certain that z1 and z0 correspond to z values
>>>>>> that precisely coincide with element interfaces.
>>>>>>
>>>>>>
>>>>>> On Sun, 19 Jan 2014, nek5000-users at lists.mcs.anl.gov wrote:
>>>>>>
>>>>>>> Hi Paul,
>>>>>>>
>>>>>>> I looked into the Peris example but It is so what same like the
>>>>>>> stenosis example with a Cosine deformation.
>>>>>>>
>>>>>>> In my case it is a pipe with conical divergent. I tried to play
>>>>>>> around the variables Xm1, Ym1 and Zm1 but the mapping doesn't go
>>>>>>> well.
>>>>>>>
>>>>>>> Could you please help me with this.
>>>>>>>
>>>>>>> Thank you,
>>>>>>>
>>>>>>> Kamal
>>>>>>>
>>>>>>>
>>>>>>> On Jan 18, 2014, at 7:26 PM, nek5000-users at lists.mcs.anl.gov wrote:
>>>>>>>
>>>>>>>> Hi Paul,
>>>>>>>>
>>>>>>>> I looked at the Helix and stenosis example but they are using
>>>>>>>> cosine functions to deform
>>>>>>>>
>>>>>>>> I tried to use a tangent function but it bends the whole pipe.
>>>>>>>>
>>>>>>>> I dint look at peris example .
>>>>>>>>
>>>>>>>> I will take a look at it and let you know.
>>>>>>>>
>>>>>>>> Thank you
>>>>>>>>
>>>>>>>> Kamal
>>>>>>>>
>>>>>>>> On Jan 18, 2014, at 7:22 PM, nek5000-users at lists.mcs.anl.gov
>>>>>>>> wrote:
>>>>>>>>
>>>>>>>>>
>>>>>>>>> Kamal,
>>>>>>>>>
>>>>>>>>> Have you looked at the peris example? The usr file there
>>>>>>>>> shows how to deform
>>>>>>>>> a pipe geometry.
>>>>>>>>>
>>>>>>>>> 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: Saturday, January 18, 2014 12:17 PM
>>>>>>>>> To: nek5000-users at lists.mcs.anl.gov
>>>>>>>>> Subject: Re: [Nek5000-users] Pipe with expansion
>>>>>>>>>
>>>>>>>>> Dear Paul,
>>>>>>>>>
>>>>>>>>> I tried many ways to map my straight pipe geometry but it does
>>>>>>>>> not seem to work properly
>>>>>>>>>
>>>>>>>>> I used something like
>>>>>>>>>
>>>>>>>>> X = X + Z * tan ( alpha )
>>>>>>>>> Y = Y + Z* tan (alpha )
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> even that dint work. could please help me with this
>>>>>>>>>
>>>>>>>>> Thank you
>>>>>>>>>
>>>>>>>>> Kamal.
>>>>>>>>>
>>>>>>>>> On Jan 17, 2014, at 2:24 PM, nek5000-users at lists.mcs.anl.gov
>>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>>> Hi Paul,
>>>>>>>>>>
>>>>>>>>>> Thanks paul. I tried working with the diverging mesh
>>>>>>>>>> modification.
>>>>>>>>>>
>>>>>>>>>> I tried to use this form of equation to modify the mesh
>>>>>>>>>>
>>>>>>>>>> z = mx + b
>>>>>>>>>> z = ny + c
>>>>>>>>>>
>>>>>>>>>> x = ( z - b ) / m
>>>>>>>>>> y = (z - c) / n
>>>>>>>>>>
>>>>>>>>>> Do you think would work ? or is there any other way to input
>>>>>>>>>> that ?
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>>
>>>>>>>>>> Kamal
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On 17/01/2014 14:14, nek5000-users at lists.mcs.anl.govwrote:
>>>>>>>>>>> Kamal,
>>>>>>>>>>>
>>>>>>>>>>> 1) To check for convergence, run your simulation for
>>>>>>>>>>> increasing polynomial orders ( lx1 in the SIZE file) and
>>>>>>>>>>> measure some consistent quantity (drag, TKE, etc). You can
>>>>>>>>>>> plot this quantity against lx1 and this should give you a
>>>>>>>>>>> good picture of how you are converging (without needing to
>>>>>>>>>>> change the physical mesh).
>>>>>>>>>>>
>>>>>>>>>>> 2) If you weren't using temperature in your simulation, you
>>>>>>>>>>> could do put the following code snippet in your userchk
>>>>>>>>>>>
>>>>>>>>>>> c-------------------------------------------
>>>>>>>>>>> integer i, ntot
>>>>>>>>>>>
>>>>>>>>>>> ntot = nx1*ny1*nz1*nelv ! total number of points in
>>>>>>>>>>> simulation (on THIS processor)
>>>>>>>>>>>
>>>>>>>>>>> do i = 1,ntot
>>>>>>>>>>> t(i,1,1,1,1) = 0.5*(vx(i,1,1,1)**2 + vy(i,1,1,1)**2 +
>>>>>>>>>>> vz(i,1,1,1)**2)
>>>>>>>>>>> enddo
>>>>>>>>>>>
>>>>>>>>>>> ifto = .true.
>>>>>>>>>>> c-------------------------------------------
>>>>>>>>>>>
>>>>>>>>>>> I've assumed here that your density is unity. This computed
>>>>>>>>>>> kinetic energy point-wise and stores it in the temperature
>>>>>>>>>>> field. The part "ifto = .true." tells Nek to output the
>>>>>>>>>>> temperature field whenever it outputs a field file. You
>>>>>>>>>>> could then view this in visit just like you would the
>>>>>>>>>>> velocity field.
>>>>>>>>>>>
>>>>>>>>>>> Hope this helps!
>>>>>>>>>>>
>>>>>>>>>>> Josh
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On Wed, Jan 15, 2014 at 9:52 AM,
>>>>>>>>>>> <nek5000-users at lists.mcs.anl.gov> wrote:
>>>>>>>>>>> Hi Paul,
>>>>>>>>>>>
>>>>>>>>>>> I will try that mapping, I created a straight pipe to do
>>>>>>>>>>> some simulations.
>>>>>>>>>>>
>>>>>>>>>>> 1) Is there a way to check my spectral convergence, so that
>>>>>>>>>>> I can do some mesh convergence study?
>>>>>>>>>>> 2) Is there a way to plot the kinetic energy in the flow ?
>>>>>>>>>>>
>>>>>>>>>>> Thank you,
>>>>>>>>>>> Kamal
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On 15/01/2014 12:14, nek5000-users at lists.mcs.anl.gov wrote:
>>>>>>>>>>>
>>>>>>>>>>> Hi Kamal,
>>>>>>>>>>>
>>>>>>>>>>> For the geometry you describe, I would apply mesh morphing
>>>>>>>>>>> to a standard straight pipe. You can create such a pipe
>>>>>>>>>>> using a subset of the mkmesh script provided in the expansion
>>>>>>>>>>> example.
>>>>>>>>>>>
>>>>>>>>>>> If your transition region is conical, then I woud make
>>>>>>>>>>> certain that the change in slope occurs at element boundaries,
>>>>>>>>>>> i.e., as in the half cross-section depicted below:
>>>>>>>>>>>
>>>>>>>>>>> _______________
>>>>>>>>>>> /| | |
>>>>>>>>>>> / | | |
>>>>>>>>>>> /| | | |
>>>>>>>>>>> ________________/ | | | |
>>>>>>>>>>> | | | | | | | |
>>>>>>>>>>> | | | | | | | |
>>>>>>>>>>> +-----+-----+---+--+---+------+------+----> z
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Paul
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On Wed, 15 Jan 2014, nek5000-users at lists.mcs.anl.gov wrote:
>>>>>>>>>>>
>>>>>>>>>>> Hi Paul,
>>>>>>>>>>>
>>>>>>>>>>> I looked at the example and it looks very helpful, but for a
>>>>>>>>>>> sudden expansion we have only two parts (i.e) the inlet pipe
>>>>>>>>>>> and the outlet pipe. Whereas in a diverging pipe we have
>>>>>>>>>>> three section (i.e,) The inlet pipe, Diverging section and
>>>>>>>>>>> the outlet pipe.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Is it possible for me to create a 2D diverging section using
>>>>>>>>>>> mesh modification and revolve it around the centre axis to
>>>>>>>>>>> get a 3d diverging pipe ?
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> or should I apply the mesh modification directly to the 3d
>>>>>>>>>>> sudden expansion pipe using usrdat2() ?
>>>>>>>>>>>
>>>>>>>>>>> Thanks,
>>>>>>>>>>> Kamal
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> On 14/01/2014 21:09, nek5000-users at lists.mcs.anl.gov wrote:
>>>>>>>>>>> Hi Paul,
>>>>>>>>>>>
>>>>>>>>>>> Thanks a lot for the update. I will take a look at as soon
>>>>>>>>>>> as possible and keep you updated with it.
>>>>>>>>>>>
>>>>>>>>>>> Thank you,
>>>>>>>>>>>
>>>>>>>>>>> Kamal
>>>>>>>>>>>
>>>>>>>>>>> On Jan 14, 2014, at 9:04 PM, nek5000-users at lists.mcs.anl.gov
>>>>>>>>>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>> Kamal,
>>>>>>>>>>>
>>>>>>>>>>> I've added an example for a step-type expansion in a pipe.
>>>>>>>>>>> New example directory
>>>>>>>>>>> is nek5_svn/examples/expansion, with a README.
>>>>>>>>>>>
>>>>>>>>>>> If you want a standard diffuser, I would use mesh-morphing,
>>>>>>>>>>> as outlined in the
>>>>>>>>>>> nek primer, which can be found on this page:
>>>>>>>>>>>
>>>>>>>>>>> http://nek5000.mcs.anl.gov/index.php/UG#Documentation
>>>>>>>>>>>
>>>>>>>>>>> I've also automated our turbulent outflow bc treatment --
>>>>>>>>>>> one simply provides an
>>>>>>>>>>> expansion factor (typically ~ 1.5) and two persistent arrays
>>>>>>>>>>> to turb_outflow(), which
>>>>>>>>>>> is now in navier5.f. This can be useful when very strong
>>>>>>>>>>> vortices are leaving the
>>>>>>>>>>> domain, which is possible for certain diffuser flow
>>>>>>>>>>> conditions (and others).
>>>>>>>>>>>
>>>>>>>>>>> Paul
>>>>>>>>>>> ________________________________________
>>>>>>>>>>> From: nek5000-users-bounces at lists.mcs.anl.gov
>>>>>>>>>>> [nek5000-users-bounces at lists.mcs.anl.gov] on behalf
>>>>>>>>>>> ofnek5000-users at lists.mcs.anl.gov
>>>>>>>>>>> [nek5000-users at lists.mcs.anl.gov]
>>>>>>>>>>> Sent: Monday, January 13, 2014 3:35 AM
>>>>>>>>>>> To: nek5000-users at lists.mcs.anl.gov
>>>>>>>>>>> Subject: [Nek5000-users] Creating a Mesh
>>>>>>>>>>>
>>>>>>>>>>> Hi
>>>>>>>>>>>
>>>>>>>>>>> Can some one please help me in this because I am new to nek
>>>>>>>>>>>
>>>>>>>>>>> 1) How can I create a .rea for a specific geometry say ' A
>>>>>>>>>>> sudden
>>>>>>>>>>> expansion pipe ' or a ' Diverging pipe '
>>>>>>>>>>>
>>>>>>>>>>> 2) What tool I should use to create that mesh.
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> Thank you
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> kamal
>>>>>>>>>>> _______________________________________________
>>>>>>>>>>> Nek5000-users mailing list
>>>>>>>>>>> Nek5000-users at lists.mcs.anl.gov
>>>>>>>>>>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>>>>>>>>>>> _______________________________________________
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>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> --
>>>>>>>>>>> Josh Camp
>>>>>>>>>>>
>>>>>>>>>>> "All that is necessary for the triumph of evil is that good
>>>>>>>>>>> men do nothing" -- Edmund Burke
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>> _______________________________________________
>>>>>>>>>>> Nek5000-users mailing list
>>>>>>>>>>> Nek5000-users at lists.mcs.anl.gov
>>>>>>>>>>> https://lists.mcs.anl.gov/mailman/listinfo/nek5000-users
>>>>>>>>>>
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>>>>>
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