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-   -   wave resistance - what software I supposed to use? (https://www.cfd-online.com/Forums/main/99120-wave-resistance-what-software-i-supposed-use.html)

leviathan March 26, 2012 13:00

wave resistance - what software I supposed to use?
 
Greetings,

Hi all, I'm a newbie here, nice to know you:)
I'm an undergraduate student. Recently, I have to evaluate wave resistance of catamaran for my final project, I've been trying to do it using ansys cfx, but I found out that ansys cfx would only give total resistance. Is there any way to evaluate wave resistance if I keep on using ansys cfx? or should I try to use other CFD software? If there are any better CFD software to evaluate wave resistance, what could it be? Please give me any suggestions cause I really don't have any idea.

Thx

lava12005 March 26, 2012 21:29

As far as I know, I don't think you can calculate the wave resistance using CFD. This is because the drag in CFD is computed by integrating the pressure and shear stress along the hull. Unless there is an exact correlation between them and the wave resistance which I never know.

Good Luck for your project!

leviathan March 27, 2012 02:15

thx lava12005 , even though you're giving me such bad news :(
then what if I want to simulate the wave, as a result of ship movement...is there any way to do it? I guess I could figure something out if I could generate the wave.

Lysistrata March 27, 2012 02:40

Search for Hullspeed or Michlet.

lava12005 March 27, 2012 03:04

Since you are using CFX, what do you mean by the wave?
Are you simulating free surface flow or just the submerged part of the ship?
If you are simulating with free surface, then the calculated drag will include the wave resistance as well..

leviathan March 27, 2012 07:21

lava12005 I mean the wave making resistance...yeah, I'm simulating free surface flow and I know that the calculated drag will include the wave resistance as well, but my final project aim is to obtain wave resistance only, so I have to somehow separate it from the calculated drag / total resistance.

Lysistrata I've ever heard about Hullspeed or Michlet but don't really know about them yet. Are they could be considered as CFD software? As far as I know they're using numerical method, aren't they?

Lysistrata March 27, 2012 08:05

Quote:

Originally Posted by leviathan (Post 351716)
lava12005 I mean the wave making resistance...yeah, I'm simulating free surface flow and I know that the calculated drag will include the wave resistance as well, but my final project aim is to obtain wave resistance only, so I have to somehow separate it from the calculated drag / total resistance.

Lysistrata I've ever heard about Hullspeed or Michlet but don't really know about them yet. Are they could be considered as CFD software? As far as I know they're using numerical method, aren't they?

They use numerical methods but they are not CFD. I think they are classical methods that use linear theory of ship waves. I have heard they are very fast and produce results as good as many CFD methods for the drag and waves.

leviathan March 27, 2012 11:43

Lysistrata hmm...sounds good, but my final project is about evaluating wave resistance using CFD , so I don't think my lecturer would agree either if I use michlet or hullspeed :(


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