I am interested in communicating WAMIT user group pls.mail me

I am interested in participating of this forum.

Regards,

Fabio.

[AlejandroVanDeWaterPatat]

As a WAMIT noob I'd like to participate

[AlejandroVanDeWaterPatat]

Well, here's a question to jump start a discussion:

When configuring my frc file for a non moored vessel (no need for damping and stiffness matrix) I need to input a mass matrix. This mass matrix is found on page 149 in Newman's Marine Hydrodynamics.

What reference point do I use?

So far I get best results if my Cog x = 0 ; CoG y = 0 : CoG z = Draught

Can anyone confirm that that is the valid input please?

Thanx

[Archduke_of_Hydrodynamia]

CoG Z is measured from the waterline

[kites]

i need to get a trial version of wamit.kindly help me out.

[akshay.kumar]

Originally Posted by Dr.K.Thiruvenkatasamy
;50889

I am interested in communicating WAMIT user group pls.mail me

I am simulating FAST version v8.1500a-bjj(12 april 2016), using the turbine model (test_24) "NREL 5.0 MW Baseline_OC3_hywind Wind Turbine for coupled dynamic analysis. therefore, the HydroDyn files (.1, .2 and .fst) are imported from the WAMIT. The output file (obtained from WAMIT) is showing very strange values for centre of buoyancy and volume. hereby i want to know that
1.) What is the reason behind these strange outcomes ? (i.e negative volumes, high centre of buoyancy )
2.) Which one volume (e.g VOLX,VOLY 'or' VOLZ) is used as undisplaced volume in FAST to arrive at the condition mention in HydroDyn_Manual section 6.8.1 (Undisplaced Position for Floating Systems). please find WAMIT output file

[Bernardo.Kahn]

Originally Posted by akshay.kumar

I am simulating FAST version v8.1500a-bjj(12 april 2016), using the turbine model (test_24) "NREL 5.0 MW Baseline_OC3_hywind Wind Turbine for coupled dynamic analysis. therefore, the HydroDyn files (.1, .2 and .fst) are imported from the WAMIT. The output file (obtained from WAMIT) is showing very strange values for centre of buoyancy and volume. hereby i want to know that
1.) What is the reason behind these strange outcomes ? (i.e negative volumes, high centre of buoyancy )
2.) Which one volume (e.g VOLX,VOLY 'or' VOLZ) is used as undisplaced volume in FAST to arrive at the condition mention in HydroDyn_Manual section 6.8.1 (Undisplaced Position for Floating Systems). please find WAMIT output file

Probably solved by now but anyway... if you look at page 25 of the WAMIT Manual you will see that the three volumes should be very close to each other so does not really matter which one you take, you could do an average. There is special consideration for bottom-mounted structures, don't know if that is your case. In this scenario the VOLZ differs from the correct volume, might even be displayed as negative as you said.


Regarding negative center of buoyancy, the usual coordinate system of WAMIT places the origin in the free-surface, so vertical body-related coordinates can be negative for the submerged sections of the body.