CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Software User Forums > ANSYS > CFX

Simulating a Wave maker in CFX

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old   March 5, 2020, 18:25
Post Simulating a Wave maker in CFX
  #1
Member
 
Saeed Pashazanousi
Join Date: Mar 2020
Location: Iran
Posts: 66
Rep Power: 6
pashazanousi is on a distinguished road
I want to simulate a Wave maker in CFX.
My model:
http://cdn.persiangig.com/download/9nOrkdEsFh/A.png/dl
I dont know why this error occur?
(DP 0) Update of the Solution component in Fluid Flow (CFX) failed: The solver failed with a non-zero exit code of : 2
pashazanousi is offline   Reply With Quote

Old   March 5, 2020, 23:56
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,749
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
Please attach your output file and some images of what you are modelling.
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Old   March 6, 2020, 08:48
Default
  #3
Member
 
Saeed Pashazanousi
Join Date: Mar 2020
Location: Iran
Posts: 66
Rep Power: 6
pashazanousi is on a distinguished road
Quote:
Originally Posted by ghorrocks View Post
Please attach your output file and some images of what you are modelling.
CFX Solver give followin error:
(DP 0) Update of the Solution component in Fluid Flow (CFX) failed: The solver failed with a non-zero exit code of : 2
I don't know why this error occur?
Analsis type is transient...
I attach an Image of my proplem model and boundry conditions
Image Link:http://cdn.persiangig.com/download/9nOrkdEsFh/A.png/dl
I define two Domin...One for Water and the other for Air...I define the boundry conditions as Image attached...I define a Experssion for moving wall velocity(=0.001*sin(100*ctstep)).
I think I should Initialize the VOF for the Domains but I don't know how?
pashazanousi is offline   Reply With Quote

Old   March 6, 2020, 09:34
Default
  #4
Senior Member
 
M
Join Date: Dec 2017
Posts: 659
Rep Power: 12
AtoHM is on a distinguished road
1) Attach your files directly to the forum ... people dont like links where they dont know what the target is.


2) Maybe a screenshot will resolve my question, but why do you need two domains? You can have both phases in one domain.


3) Setting up multiphase simulations and initialising the phases (specifically for water and air setup) is covered in the cfx tutorials. E.g. 10. Free-surface flow over a bump.
AtoHM is offline   Reply With Quote

Old   March 6, 2020, 09:43
Question Wave Maker
  #5
Member
 
Saeed Pashazanousi
Join Date: Mar 2020
Location: Iran
Posts: 66
Rep Power: 6
pashazanousi is on a distinguished road
Thanks for your attention
A.jpg
pashazanousi is offline   Reply With Quote

Old   March 6, 2020, 22:49
Default
  #6
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,749
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
It is a bad idea to make a domain boundary align with a free surface. It means the difficult numerics of the free surface is placed right on the bit where coupling over the domain boundary is difficult (at the interface).

Make your simulation a single domain.

The error messages you report are workbench level error messages which tell you nothing. You need to look in the CFX output file (.out) for the details. That is why I asked for the output file in the first place.
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Old   March 11, 2020, 15:15
Default Wave Maker
  #7
Member
 
Saeed Pashazanousi
Join Date: Mar 2020
Location: Iran
Posts: 66
Rep Power: 6
pashazanousi is on a distinguished road
Quote:
Originally Posted by ghorrocks View Post
It is a bad idea to make a domain boundary align with a free surface. It means the difficult numerics of the free surface is placed right on the bit where coupling over the domain boundary is difficult (at the interface).

Make your simulation a single domain.

The error messages you report are workbench level error messages which tell you nothing. You need to look in the CFX output file (.out) for the details. That is why I asked for the output file in the first place.
I simulate the piston type wave maker with wall velocity(0.5cos(10*time)).I do it in transient Analysis type and active dynamic mesh in Unspecified.
I think some thin is wrong...because result is not acceptable...
I cant upload the video here...
I upload some pdf and a video about my case in WE transfer:
https://we.tl/t-fpARQ9vS97
https://we.tl/t-MYIlet5TUL
pashazanousi is offline   Reply With Quote

Old   March 28, 2020, 01:34
Default Wave Maker
  #8
Member
 
Saeed Pashazanousi
Join Date: Mar 2020
Location: Iran
Posts: 66
Rep Power: 6
pashazanousi is on a distinguished road
i managed to simulate the wave maker model in cfx . but the desired results were not achieved . in fact , the results do not match with the theory . I did the simulation in accordance with the Article .I attached the paper file and simulation results link below.
https://we.tl/t-1vZ8kX5nql
pashazanousi is offline   Reply With Quote

Old   March 28, 2020, 04:26
Default
  #9
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,749
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
I don't have time to look at your results file and I don't click on strange links either.

Post images directly on the forum, and attach your output file directly on the forum. If you don't know how to do this have a look at the FAQ: https://www.cfd-online.com/Wiki/Ansy...n_the_forum.3F
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Old   March 31, 2020, 15:57
Default
  #10
Member
 
Saeed Pashazanousi
Join Date: Mar 2020
Location: Iran
Posts: 66
Rep Power: 6
pashazanousi is on a distinguished road
thank you...I solve that problem myself...But I ask a quesion...
I want to plot a point's elevation of water free surface According to simulation time.
for example I want to plot free surface elevation in x=20 from t=0 s to t=20 s.
aaaaaa.jpg
pashazanousi is offline   Reply With Quote

Old   March 31, 2020, 17:22
Default
  #11
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,749
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
To get the average water height on a surface you can work out the wetted area by areaInt(water.volume fraction)@surface. You can calculate the average water height from there.

You can also do a line integral on a vertical line to get height at a point.
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Old   April 2, 2020, 09:25
Default Wave Maker
  #12
Member
 
Saeed Pashazanousi
Join Date: Mar 2020
Location: Iran
Posts: 66
Rep Power: 6
pashazanousi is on a distinguished road
Thank you...I have an other problem...
I want to select some particle of water to plot path vs time...how could I define some particle of water?
I want to plot path of 10 particle in some planes with equal span in x direction...
what should I do?
Untitled.jpg
pashazanousi is offline   Reply With Quote

Old   April 2, 2020, 18:25
Default
  #13
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,749
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
I assume you want these particles to follow the transient flow.

In that case you are going to have to rerun the simulation, you cannot do it post-processing. In the solver you have a few options:
* (easy) Add an additional convection variable, initialised to zero everywhere but 1 at your seed points. They will then convect around the flow. The problem with this approach is you are not modelling particles as such and the additional variable will dissipate away eventually.
* (harder) Define a lagrangian particle phase. Define the particles to have almost zero mess and lots of drag. You can then track their motions in the post processor. This will slow the simulation down quite a bit.
* (have not checked if this is possible) I vaguely recall there is a massless particle option in CFX. This would be the best way of doing it, but I am not sure how it is done, or even if it really is possible. I will leave further research of this comment to you
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Old   April 3, 2020, 01:03
Default
  #14
Member
 
Saeed Pashazanousi
Join Date: Mar 2020
Location: Iran
Posts: 66
Rep Power: 6
pashazanousi is on a distinguished road
thank you...But How I should define particles?...I want to define 10 particles in@some plan to plot particles paths and Velocties...in CFX-Pre how I define these particles?
pashazanousi is offline   Reply With Quote

Old   April 3, 2020, 04:12
Default
  #15
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,749
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
The only way I know to seed a flow with lagrangian particles at specific locations is with a user fortran routine to set the particle locations.
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Old   April 4, 2020, 04:06
Default
  #16
Member
 
Saeed Pashazanousi
Join Date: Mar 2020
Location: Iran
Posts: 66
Rep Power: 6
pashazanousi is on a distinguished road
Quote:
Originally Posted by ghorrocks View Post
The only way I know to seed a flow with lagrangian particles at specific locations is with a user fortran routine to set the particle locations.
OK....How I should do that?...I don't know what should I do...There are any tutorial for particle path in VOF Multiphase model?
pashazanousi is offline   Reply With Quote

Old   April 4, 2020, 04:24
Default
  #17
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,749
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
No, the VOF Multiphase model is a Eularian model. You don't want that one. You want the Lagrangian particle tracking model.

It has been a while since I looked, but I think there is an example fortran file in the CFX installation somewhere. Have a look in the CFX documentation for user fortran for particles.
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Old   April 4, 2020, 07:05
Default
  #18
Senior Member
 
M
Join Date: Dec 2017
Posts: 659
Rep Power: 12
AtoHM is on a distinguished road
Just a short warning: the particle tracking model gives you HUGE result files depending on how many particles you have inside the domain. Easily reaches 10 GB an more for a .res file. Make sure you have the resources to handle this as well.
AtoHM is offline   Reply With Quote

Old   April 4, 2020, 07:19
Default
  #19
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,749
Rep Power: 143
ghorrocks is just really niceghorrocks is just really niceghorrocks is just really niceghorrocks is just really nice
The huge result files are when you have zillions of particles. From what I understand of this application there should only be a handful of particles, so file size increase should be minimal.
__________________
Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.
ghorrocks is offline   Reply With Quote

Old   April 5, 2020, 04:19
Default
  #20
Member
 
Saeed Pashazanousi
Join Date: Mar 2020
Location: Iran
Posts: 66
Rep Power: 6
pashazanousi is on a distinguished road
Quote:
Originally Posted by ghorrocks View Post
No, the VOF Multiphase model is a Eularian model. You don't want that one. You want the Lagrangian particle tracking model.

It has been a while since I looked, but I think there is an example fortran file in the CFX installation somewhere. Have a look in the CFX documentation for user fortran for particles.
I just need some particles path...If I don't use VOF Model then How I simulate the free surface tank?...How I define materials and simulation setup?...I search Web,papers and every thing to learn but I can't...I'm confused
Untitled.jpg
pashazanousi is offline   Reply With Quote

Reply

Tags
ansys 14 cfx, cfx

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
wave maker wave maker CFX 12 July 10, 2020 04:35
Coffee Coffee Maker Station Ways to Make lichypanta Main CFD Forum 0 June 16, 2016 03:18
Simulating Ice Accretion in CFX agner583 CFX 3 February 11, 2014 00:50
solving ocean wave with Fluent or CFX? gholamghar Main CFD Forum 1 March 21, 2009 12:49
Question about the shock wave in CFX software nucharin Main CFD Forum 1 January 25, 2005 08:26


All times are GMT -4. The time now is 14:09.