[Nek5000-users] Pipe with expansion
nek5000-users at lists.mcs.anl.gov
nek5000-users at lists.mcs.anl.gov
Mon Jan 20 14:36:30 CST 2014
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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>>>>>>>>> _______________________________________________
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>>>>>>>>>
>>>>>>>>>
>>>>>>>>> --
>>>>>>>>> Josh Camp
>>>>>>>>>
>>>>>>>>> "All that is necessary for the triumph of evil is that good men do nothing" -- Edmund Burke
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> _______________________________________________
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