frienship-michlet integration

[Chris Pap]

Dear Fellows

My name is Chris Papandreou and i am a student in the school of naval architecture and marine engineering at NTUA in Greece.My diploma thesis is in ship design and optimisation with Mr A. Papanikolaou.
I was trying to call michlet from friendship and to create and automatic design engine for optimisation (michlet is awesome for this purpose as it combines valid and quick results),
but i am facing a problem. In order to find the resistance in michlet user interaction is needed(pressing R,T). I discussed this matter with Mattia Brenner(from friendship) and even Mattia had not a solution. So i want to ask you if there is something that i miss? Perhaps a version of michlet that runs in batch mode or if there is anythng else that i can try to achieve my purpose.
I want to thank you in advance for your time and assistance.

Best regards,
Chris Papandreou

[Leo Lazauskas]

Originally Posted by Chris Pap

Dear Fellows

My name is Chris Papandreou and i am a student in the school of naval architecture and marine engineering at NTUA in Greece.My diploma thesis is in ship design and optimisation with Mr A. Papanikolaou.
I was trying to call michlet from friendship and to create and automatic design engine for optimisation (michlet is awesome for this purpose as it combines valid and quick results),
but i am facing a problem. In order to find the resistance in michlet user interaction is needed(pressing R,T). I discussed this matter with Mattia Brenner(from friendship) and even Mattia had not a solution. So i want to ask you if there is something that i miss? Perhaps a version of michlet that runs in batch mode or if there is anythng else that i can try to achieve my purpose.
I want to thank you in advance for your time and assistance.

Best regards,
Chris Papandreou

Hi Chris,
I have not released a free, batch-mode version of Michlet.
However, I will release Flotilla version 5.0 in the next few weeks. That
is a text-based program that can be run in batches and it is relatively
easy to change the input files using other programs you can write yourself.

Also, if you are just considering monohulls and you don't need estimates of sqaut, Ulimich might be Ok for your project.
It can be run in batch mode.

Good luck with your studies!
Leo.

[Chris Pap]

Dear Leo

Thank you for your interest and your quick reply.
Unfortunatelly i am trying to optimise a swath so ulimich cannot help me right now(although i will download it, these things are always usefull).
I looking forward to run Flotilla then in the next weeks.
Thank you again, and congatulations about michlet.

Best regards
Chris Papandreou

[Leo Lazauskas]

Originally Posted by Chris Pap

Dear Leo

Thank you for your interest and your quick reply.
Unfortunatelly i am trying to optimise a swath so ulimich cannot help me right now(although i will download it, these things are always usefull).
I looking forward to run Flotilla then in the next weeks.
Thank you again, and congatulations about michlet.

Best regards
Chris Papandreou

I strongly suggest that you look at this thread:
SWATH resistance predictions using Michlet

As you will see, SWATH require some special treatment vis-à-vis form drag.
In general, you do not need to use any form factors for most thin hulls,
however:
(1) SWATH usually have a rounded nose (which violates the thin-ship
assumption) and
(2) It is best to use two form factors: one for the strut and another for the
torpedo-like lower portion.

These dual form factors are a rough-as-guts way of accounting for (1) and
possible separation at the intersection of the strut and bulb.

The 1st post in the thread also contains a short report that compares
Michlet predictions with towing tests of a model SWATH. The strut and bulb
are comprised of mathematical shapes, so you should be able to create the
offsets yourself. One way is to use Michlet's mathematical hull series and
combine them into a SWATH strut-bulb combination. It's a bit messy, but
it will actually give very accurate (4 or 5 figure) accuracy for the shapes.

[DCockey]

Question for Leo: My understanding is the wave amplitude fields generated in Michlet for a multihull vessel are the same as would be obtained if:
1) The wave amplitude fields for each hull in isolation were generated independently in Michlet.
2) Each wave amplitude field was shifted in space to correspond with the position of corresponding hulls in the multihull configuration.
3) The wave amplitude fields were combined by superposition to obtain the wave amplitude field for the multihull.
Also, my understanding that calculating wave drag of a multihull requires use of the combined wave amplitude fields due to non-linearity of the wave drag with wave amplitude.
Is this correct?

Update: I had previously asked a related question which Leo had answered in post #27 of the thread which Leo referenced above. SWATH resistance predictions using Michlet

[Leo Lazauskas]

Originally Posted by DCockey

Question for Leo: My understanding is the wave amplitude fields generated in Michlet for a multihull vessel are the same as would be obtained if:
1) The wave amplitude fields for each hull in isolation were generated independently in Michlet.
2) Each wave amplitude field was shifted in space to correspond with the position of corresponding hulls in the multihull configuration.
3) The wave amplitude fields were combined by superposition to obtain the wave amplitude field for the multihull.
Also, my understanding that calculating wave drag of a multihull requires use of the combined wave amplitude fields due to non-linearity of the wave drag with wave amplitude.
Is this correct?

Update: I had previously asked a related question which Leo had answered in post #27 of the thread which Leo referenced above. SWATH resistance predictions using Michlet

Yes to all, without the effects of boundary displacement thicknesses and
without viscous wave damping. Otherwise, there is also a weak Reynolds
number dependence and an influence from the other hulls in the ensemble.
In Flotilla there are some other interactions between the demihulls I have
included that are not in Michlet.