This would involve simulating two ships and the way to transfer crews (gangway rigid/flexible etc.). Using CFD would be very complicated and computationally inefficient. Has anyone tried this?
It would depend on two things: absolute numbers and density. The rule is: the mean free path has to be at least several times smaller than the smallest distance between walls in the system.
Assuming that the smallest distance in your scenrio is the length of the gangway (the width doesn't matter because noone walks in that direction) then you could use fluid equations if anyone who wants to cross the gangway would bump into another person before he got halfway through. In other words, there aways have to be at least two people on the gangway at any given time
This can be done using a general hydrodynamics code called Orcaflex from Orcina.com. You would need multi-body RAO's for the ship motions in waves. WAMIT or WADAM can provide them or FD-Waveload or maybe AQWA. Orcaflex allows you to also include layered densities and directional currents and waves and non-linear fenders and mooring line properties. I've done this modeling half a dozen times and it's not too difficult as long as you have good input data. Search for papers under HICASS which is a project Oceaneering did that moved containers at sea instead of people but a lot of the physics is the same. CFD is not going to work for this, it's the wrong tool, much too expensive to setup and run. The others I cited can run in real time or faster on a laptop or desktop.
Yes, it is possible but it will be overkill. If you take Navier-Stokes equation and apply a series of assumptions: incompressible, inviscid, small displacements, you will get Laplace equation. This is what WAMIT, WADAM, or AQWA solve. This is what Sean Kery has suggested and it is a much better approach because you will be able to quickly try different parameters (wave directions, gap between vessels etc.). What you are trying to solve is the dynamics of hydrodynamically and structurally coupled floating bodies. See video at www.compmech-inc.com/dynasos
My answer is the practical mechanical / ocean engineer approach That I believe can results in safe and effective hardware designs. These problems are solvable if quite tricky to do safely. I thing CFD and some of the Operational research approaches might get bogged down in meshing and constraints administrivia that play havoc in simulation space but don't necessarily exist the same in the physical world.
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