[Nek5000-users] Pipe with expansion
nek5000-users at lists.mcs.anl.gov
nek5000-users at lists.mcs.anl.gov
Sun Jan 19 19:00:52 CST 2014
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
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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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