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#1 |
New Member
Angus Bishop
Join Date: Apr 2012
Posts: 17
Rep Power: 14 ![]() |
Sorry , this should be my last question
![]() I have a hollow cylindrical hull shape for a boat , I'm running a rigid body simulation to show stuff , I have timesteps of 0.025 seconds but after the 7-8th one the boat jumps out of the water by around 1m for the previous timesteps it would move only 1cm or less. Have i done something fundamentally wrong? Or does CFX not handle flow inside and outside hollow tubes very well? Thanks in advance for replies |
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#2 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,746
Rep Power: 143 ![]() ![]() ![]() ![]() |
I've heard of jumping beans but not jumping boats
![]() And no need for apologies, the forum is here to ask questions and you are welcome to do so. It sounds like you have a numeric instability in your simulation. You need to stablise the rigid body motions. I have little experience in rigid body stuff so cannot help you with exactly how to do this. |
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#3 |
New Member
Angus Bishop
Join Date: Apr 2012
Posts: 17
Rep Power: 14 ![]() |
That sounded fancy
![]() Now just hope someone knows how to sort that out. Running simulations at this stage are taking about an hour so trial and error is out of the question. |
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#4 |
New Member
Angus Bishop
Join Date: Apr 2012
Posts: 17
Rep Power: 14 ![]() |
Also how would i go about takingg just the value of an expression without dimensions at then putting dimensions on it?
I have a formula that pumps out values in seconds at the moment and i was it to be in meters per second. |
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#5 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,746
Rep Power: 143 ![]() ![]() ![]() ![]() |
Have a look at the numerical controls for rigid bodies. There will be stability controls there, that is what you need to play with.
CEL uses units for your own protection - you cannot just convert a time measurement to a velocity. Of course you can just say vel = 1 [m]/time_var and then you have m/s but most of the time this is not somethign you want to do. |
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