calculating force on object being lowered/dropped into water

PLI

Any info/resources on calculating the hydrodynamic force on an object when it hits the water surface with constant velocity?

cheers

Simon Bridge

Welcome to PF.
You mean something like this one or more general like this one?

Put another way - at what level should we be pitching this?
If just lowering an object into water, and at secondary school level, you'd only want to worry about bouyancy and, maybe, surface tension.... for eg.

PLI

thanks simon,

both are good.
trying to get good understanding at "tertiary level", so that i can then put it into a design equation at "secondary school level" :)

haven't had a good read through either yet but i'm ok with submerged buoyancy, drag etc. it's the force acting on the object as it hits the water i need to understand better.

out of interest - do you have drag force and drag coefficient for a square object?

Simon Bridge

Not lying around no.
These things are not trivial to work out - especially as you'll get turbulent motion.
It's usually easier just to do an experiment.