Force per square metre due to tidal conditions

[Joseph Murphy]

I’m all googled out trying to work this one out. So, perhaps there is a math-magician on here who has the answer.

How do I calculate the horizontal force per square metre acting on an rov and/or subsea tool at varying flow rates (currents) and at various depths, densities, temperatures of seawater? I know how to work out the force due to hydrostatic pressure, but am interested in knowing the effect of current on different sizes and power ratings of rov’s.

Alternatively, does anyone know if a set of tables have been published on this topic?

[Donald Faulds]

I’m all googled out trying to work this one out. So, perhaps there is a math-magician on here who has the answer.

How do I calculate the horizontal force per square metre acting on an rov and/or subsea tool at varying flow rates (currents) and at various depths, densities, temperatures of seawater? I know how to work out the force due to hydrostatic pressure, but am interested in knowing the effect of current on different sizes and power ratings of rov’s.

Alternatively, does anyone know if a set of tables have been published on this topic?

Morrison’s equation: http://en.wikipedia.org/wiki/Morison_equation

Ignore the first term about wave loading. Temperature and pressure effects are trivial. The second term is about current drag. ROVs are like bricks and the drag factor Cd is about 2.

I think this is about as much as I can do without starting to give a course on hydrodynamics, cheers. 😀

[Joseph Murphy]

Thank you, DonF.

[Savante]

We were involved in measuring the drag co-efficients for a 100ft tall well intervention system; you’ll need a 3D printer – if you’ve got CAD, then render a physical scale model and then drag test in a water tank.

Best Regards,

Grant

[Author]

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