Waves and a floating body... in CFX?

salvooch · January 9, 2011, 20:52

Hi, I'm relatively new to CFD, so please bear w/ me...

I want to look at the effectiveness of a breakwater on decreasing the sea state in open water, but the breakwater is a floating at the air/water interface due to it's own buoyancy.

Are you able to have a floating body in CFX? The minimal work I've done was where the object is in the flow field (airfoils, etc.).

I've done the 'flow over a bump' tutorial and gotten wave action by varying the speed over the bump, but not sure if this is the most effective way to 'induce' waves. Am I even using the right software (CFX)?

Thanks in advance to any help!

ghorrocks · January 10, 2011, 16:33

This is best done in CFX V13 using immersed solids and the 6 DOF solver.

salvooch · January 12, 2011, 17:30

I'll do the immersed solids tutorial (buoy) an see if I the output is useable for what I want to look at. Thanks, and I welcome any additional information!

salvooch · January 13, 2011, 01:36

Ok, after running the tutorial, looks like what I need. That said, does anyone know how to induce different sea states? or create a wave pool?

Meaning, anyone already run code to induce sea state 2, 3, etc., or know what type of movement of the boundaries has to be done in order to induce waves of a specific period (like a wave pool or test tank would have)?

Thanks

ghorrocks · January 13, 2011, 16:54

Do a search on the forum for modelling ocean waves. There was a post on it some time ago which defined a good model for ocean waves.

salvooch · January 13, 2011, 21:48

Thanks, I'll do a search tonight

xlxc34 · January 14, 2011, 05:04

Sounds like Orcaflex could be suitable software to me.

ghorrocks · January 15, 2011, 06:45

Or ANSYS AQUA. This will be a tricky model to get accurate in any CFD code.

salvooch · January 19, 2011, 17:53

Thanks. For now (at least), I'm going to try the 6 DOF/immersed body method (tutorial 32).

For some reason, my university's Workbench doesn't have the hydro module available to tie into AQWA, yet we have AQWA available... Either way, I can't seem to get it to launch AQWA, and am in the process of asking IT and various CFD profs for help w/ it.

xlxc34 · January 20, 2011, 04:03

I don't know if this will be of any help, but Stephen Salter at Edinburgh university has done a lot of research on wave making. His papers might save you some time getting the type of waves that you want.

January 9, 2011, 20:52	Waves and a floating body... in CFX?	#1
salvooch New Member Join Date: Dec 2010 Posts: 19 Rep Power: 16	Hi, I'm relatively new to CFD, so please bear w/ me... I want to look at the effectiveness of a breakwater on decreasing the sea state in open water, but the breakwater is a floating at the air/water interface due to it's own buoyancy. Are you able to have a floating body in CFX? The minimal work I've done was where the object is in the flow field (airfoils, etc.). I've done the 'flow over a bump' tutorial and gotten wave action by varying the speed over the bump, but not sure if this is the most effective way to 'induce' waves. Am I even using the right software (CFX)? Thanks in advance to any help! Last edited by salvooch; January 10, 2011 at 15:19.

January 13, 2011, 01:36	Tutorial done...	#4
salvooch New Member Join Date: Dec 2010 Posts: 19 Rep Power: 16	Ok, after running the tutorial, looks like what I need. That said, does anyone know how to induce different sea states? or create a wave pool? Meaning, anyone already run code to induce sea state 2, 3, etc., or know what type of movement of the boundaries has to be done in order to induce waves of a specific period (like a wave pool or test tank would have)? Thanks

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January 10, 2011, 16:33		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,934 Rep Power: 145	This is best done in CFX V13 using immersed solids and the 6 DOF solver.

January 12, 2011, 17:30		#3
salvooch New Member Join Date: Dec 2010 Posts: 19 Rep Power: 16	I'll do the immersed solids tutorial (buoy) an see if I the output is useable for what I want to look at. Thanks, and I welcome any additional information!

January 13, 2011, 16:54		#5
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,934 Rep Power: 145	Do a search on the forum for modelling ocean waves. There was a post on it some time ago which defined a good model for ocean waves.

January 13, 2011, 21:48		#6
salvooch New Member Join Date: Dec 2010 Posts: 19 Rep Power: 16	Thanks, I'll do a search tonight

January 14, 2011, 05:04		#7
xlxc34 New Member Pete Greaves Join Date: Jan 2011 Posts: 6 Rep Power: 16	Sounds like Orcaflex could be suitable software to me.

January 15, 2011, 06:45		#8
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,934 Rep Power: 145	Or ANSYS AQUA. This will be a tricky model to get accurate in any CFD code.

January 19, 2011, 17:53		#9
salvooch New Member Join Date: Dec 2010 Posts: 19 Rep Power: 16	Thanks. For now (at least), I'm going to try the 6 DOF/immersed body method (tutorial 32). For some reason, my university's Workbench doesn't have the hydro module available to tie into AQWA, yet we have AQWA available... Either way, I can't seem to get it to launch AQWA, and am in the process of asking IT and various CFD profs for help w/ it.

January 20, 2011, 04:03		#10
xlxc34 New Member Pete Greaves Join Date: Jan 2011 Posts: 6 Rep Power: 16	I don't know if this will be of any help, but Stephen Salter at Edinburgh university has done a lot of research on wave making. His papers might save you some time getting the type of waves that you want.