Water current force

[Azawakh]

Greetings,

I am presently trying to simply calculate the force exerted on a cable in kg by water current according to its current velocity. Basically, I have to install moorings in a fast water environment and I am trying to calculate how strong a cable I should install and what size weight I should put on the bottom of the river so the current won't take it away. THanks in advance.

 

[dicksewerrat]

would it be the weight of the water times velocity times area of the side of the cable?

Richard A. Cornelius, P.E.

http://WWW.amlinereast.com

 

[LincolnPE]

Pd = 0.5*ρ*V²

Fd = Pd*A

 

[Azawakh]

Perfect thank you very much!!

 

[beej67]

I may be wrong because this isn't totally my field, but I think Lincoln's technically missing a drag coefficient in there. The drag coefficient should be pretty close to 1, though, so it should probably still work as stated.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com

 

[psmart]

That will give you the force against the cable, but I suspect you want the tension in the cable, which forms a catenary under the influence of the current and gravity.

Also, I would expect that the force exerted by the object being moored would be the dominant factor in determining the cable strength.


Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[LincolnPE]

Need to do free body diagrams for the cable tension. Along with gravity forces, you will also have buoyant forces working on the objects on the free body diagrams.