Modelling of Floating Vessels

[sigaskell 0]

Has anyone attempted to model the effect that floating vessels may have on flow dynamics in 2D?  I am dealing with an estuarine river site with permanent docks alongside the banks.  There are large (>20 m wide, >150 m in length) barge vessels and ships frequently docked through the project reach and the draft of these boats would ordinarily reduce the depth of the river in the dock area by 50%.  I am modelling in 2D so one thought I have had would be to incorporate a geometry modification whereby the depth of water is reduced to that between the keel of the boats and the river bed.  However, I also wonder if I need to account for the fact that there would likely be greater drag underneath these boats than would otherwise occur with a reduced depth (i.e. because underneath the boat there would be drag from both the hull and the river bed rather than drag only at the river bed if there was open air above).  This would be accounted for by increasing Manning's roughness slightly.  Any thoughts, research or feedback would be greatly appreciated.

Thanks!

[peteraylett 0]

Hi there,

Have you considered using the 2d_fcsh, flow constriction shape? Section 6.12.2 in the 2017 manual. (or even the layered FC shape, but I don't suppose much water goes over your vessels!)

This type of object specifically supports floating decks (type "FD"), so your vessels can rise and fall with the tide, but maintain a constant draft. This also lets you specify a Manning's n value for roughness of the underside of the obstruction.

Hope that helps! Let us know how you get on or if you've further questions.

PHA.

[sigaskell 0]

Perfect - thanks Peter!