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

Soliton modeling

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

Reply
 
LinkBack Thread Tools Display Modes
Old   January 17, 2012, 23:16
Question Soliton modeling
  #1
New Member
 
Join Date: Jan 2012
Posts: 11
Rep Power: 5
svanmunster is on a distinguished road
Hi all,

I currently have no experience with CFD at all however my client has asked me to model a solitary bow wave (Soliton) created by a boat at near critical speed (Froudes number = 1) with the intent on determining potential wave heights and total drag for different configurations.

I have access to CFX only. I am just wondering if this is possible in CFX and whether it will be hard to model. Also does CFX have the capabilities to model breaking waves?

I am going to begin to do the inbuilt CFX tutorials to extend my knowledge on CFD. Some steps as to where to start would be greatly appreciated.

Thanks in advance!
svanmunster is offline   Reply With Quote

Old   January 18, 2012, 00:14
Default
  #2
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,824
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Quote:
I am just wondering if this is possible in CFX
Yes

Quote:
and whether it will be hard to model.
Yes, especially if you have no experience in CFD.

Quote:
Also does CFX have the capabilities to model breaking waves?
Yes, but only by setting it up correctly such that it can do it.

This is really quite a tricky problem. How are you going to deal with the trim of the boat? How are you going to model the free surface? What boundary conditions are required to keep wave reflections under control? Each of these questions is complex enough you could do a PhD on it, so make sure you are aware of the complexity of this simulation.

If you are new to CFD then you have a lot of learning to do. I hope you have set aside several months for this. Start with tutorials sure, but the real challenge starts when you try to get accurate answers. The tutorials do not discuss accuracy at all (in my opinion they should so people know what is really involved).
ghorrocks is offline   Reply With Quote

Old   January 18, 2012, 05:25
Default
  #3
New Member
 
Join Date: Jan 2012
Posts: 11
Rep Power: 5
svanmunster is on a distinguished road
Thanks for your reply. I know I know its a big ask. The positive thing is I do have plenty of time.

Also the model is actually semi-fixed as in it is not allowed to trim or pitch, hopefully that will be make it easier.

I will be sure to keep you posted with my progress.

Thanks
svanmunster is offline   Reply With Quote

Old   January 18, 2012, 06:30
Default
  #4
Super Moderator
 
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 10,824
Rep Power: 85
ghorrocks has a spectacular aura aboutghorrocks has a spectacular aura aboutghorrocks has a spectacular aura about
Yes, a fixed body will take one of the big unknowns out of the simulation. In that case I recommend the following:

1) Start off with the tutorials. But they simply explain what buttons to press and give little insight into the theory and practise of getting accurate solutions.
2) Choose a simple benchmark case. Make start off with single phase and something with published accurate answers. Maybe flow over a back step or the lid driven cavity. Only when you are getting accurate solutions to these really simple simulations do you proceed.
3) Choose more complex benchmarks which start focussing on your simulation topic. Is there published benchmark flows of surface waves on a reference body? This would be ideal. Alternately tank sloshing or something similar would be good. Again, only after you get this accurate do you proceed.
4) By now you should have a pretty good idea of what is involved in getting and accurate CFD simulation in your two-phase flows. Now you can attempt your first simulation on your body.

For most people new to CFD this will take several months to work though.
ghorrocks is offline   Reply With Quote

Reply

Thread Tools
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 On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Soliton modeling svanmunster Main CFD Forum 4 January 18, 2012 12:09
May Focus Area: Turbulence Modeling Jonas Larsson CFD-Wiki 0 May 2, 2006 11:48
Modeling Flow/Saturation/Absorption in Fibers Gene Dougherty Main CFD Forum 0 June 6, 2003 14:49
Solid Modeling Chris Main CFD Forum 10 July 2, 2002 07:12
CFD Modeling of Two-phase Flow in Small Dia.Tubes Eric Poindexter Main CFD Forum 2 September 22, 2000 09:21


All times are GMT -4. The time now is 15:32.