How to get hydrodynamic derivatives from vessel struct?
MeetGandhi-Honda opened this issue · comments
Hey @cybergalactic,
I am trying to use MSS with my own vessel. For the same, I want to know how to get the hydrodynamic derivatives (https://github.com/cybergalactic/MSS/blob/master/VESSELS/mariner.m#L57-L73) from the vessel struct (For instance, https://github.com/cybergalactic/MSS/blob/master/HYDRO/vessels_wamit/tanker/tanker.mat). I am asking as the vessel structure does not have variables with names associated to the hydrodynamic derivatives. Is there a way to extract the hydrodynamic derivatives from the vessel struct?
I am looking forward to your response.
Regards
The vessel struct is used for seakeeping theory where the potential coefficients are computed using hydrodynamic software. while hydrodynamic derivatives are used in maneuvering theory. To obtain the hydrodynamic derivatives you must run a PMM test (model basin test) or full-scale test (time series and curve fitting). The relationship between these two methods is briefly described in chapters 5 and 6 of my Wiley textbook published in 2021. As you can see from the lecture notes you can map added mass and linear damping to hydrodynamics derivatives using the "zero-frequency" assumption. This will give you a linear maneuvering model. Alternatively, you can use the clarke83.m function in the MSS toolbox to compute the linear hydrodynamic derivatives from regression analysis of a look-alike ship.
Hey @cybergalactic,
I was able to load lecture slides (https://www.fossen.biz/wiley/) a few days back; however now I cannot. Is there a way to get hold of those slides?
Regards