PDStrip, free strip theory program

[CWTeebs]

I'm having trouble finding any documentation about the underlying theory. Is it similar to VisualSMP?

[Tim B]

The underlying theory for PD-Strip is well documented, and is available from the software repository. Here : http://opendynamics.cvs.sourceforge....on.ps?view=log

The thoery behind openDynamics is quite detailed for each individual component. Essentially, it is based on adding up all the forces at each point on the components, then moving the model accordingly. Each component will have it's own detailed theory, which will be described separately (for waves, foils, hull etc). openDynamics is not based on a strip-theory method. It is (primarily) a time-domain, volumetric method.

In conclusion, pdStrip is similar to VisualSMP (just without most of the visual at the moment), and openDynamics isn't at all similar.

Hope this helps,

Tim B.

[imita_seixo]

Dear Gtampier:

I found your post really interesting. Do you have the geometry and results for this barge? We are having problems matching a similar case with both codes.

Sincerely.

Antonio

Originally Posted by gtampier

I have some good news. The Absolute terms (1, 2, 3) for translations and rotations are the 6 RAOs. I quote the user manual in p.10:

If you give as input different wave lengths you will get results for different encounter freqs. Here as example some results:

wave circ. frequency 1.700
 encounter frequency  3.173
 wave length           21.33
 wave number          0.2946
 wave angle           180.0
 speed                 5.00
  wetted transom?     T
  log(determinant)     87.82  12.41
              Real part(1)  Imagin.part(1)    Abs(1)  Real part(2)  Imagin.part(2)    Abs(2)  Real part(3)  Imagin.part(3)    Abs(3)
 Translation        -0.000       -0.011        0.011        -0.000       -0.000        0.000         0.100       -0.002        0.100
 Rotation/k          0.000       -0.000        0.000        -0.000       -0.006        0.006         0.000       -0.000        0.000

I'm comparing results of PDSTRIP with SEAWAY and SEAKEEPER (Maxsurf), and for a box-shaped barge they seem OK. I'm calculating a containership now, I will tell you about the results later...