Michlet over estimates the total resistance

Hi

Im trying to optimize a trimaran hull, which I later will verify against CFD. I already have som estimations on what the total resistance should be without any changes. From Michlet i get almost the 2x as much. Also, If i which off/on the slender body setting, nothing happens?

Help please

- Andrea

 

Have you possibly done your base caser CFD using a symmetry plane and therefore only see the results for half a hull?

 

I have used symmetry plane, but I have included this in my calculations. My main hull have a very complex geometry, I have found that this may have caused some problems, any experience with this?

 

Being estimates...how do you know if this is correct? You need a confirmed baseline datum that is correct and verifiable by several sources, otherwise, you will be chasing your own tail!

 

In my humble opinion, all power calculations (and many other calculations of naval architecture) are estimates. So, in my opinion, do not worry about your tail.

 

How do the results of Michel integral based Michlet compare with results using panel based programs using say Rankine source distribution based on say Havelock/Newman green functions? I find Michlet's Wave Resistance prediction about 20-30% lower when compared with model test based predictions for an existing trimaran.