force moments on vertical flanged pipes moving in fluid

[concretebar]

Please we have a pipe hanging by a boat which is moving water.
We have 3 pieces of pipe connected by bolted flanges portion in water
TOP PART WITH A TEE WHICH IS SUPOORTED ON THE BOAT
1. We want to know the forces that act on this vertical pipe as the boot sails at V m/s?
2. How we calculate the torsion at the tee
3. How you calculate the stresses on the bolted flange
Regards

 

[LittleInch]

It's the reverse of force on circular cylinders / risers - there is lots of information on that.

However depending on how deep you go, the current may vary with depth unless you're travelling across a lake?

Biggest issue is likely to be vortex induced vibration or if you get close tot he natural frequency, large swings and swaying of the column.

Have a search around the offshore structure engineering forum to see what is there.

I think any tee is likely to bend once you get any appreciable velocity.

Sizes, length of pipe and velocity make a big difference - can you say what these are?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

Maybe you want to use the drag equation.

https://physicscalc.com/physics/drag-equation-calculator/

Cd for a tube is 0.6
If there's waves, or other dynamics, you may need to increase that by at least double.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[LittleInch]

I was hoping someone could come up with a formula....

Item 2 - It's bending moment, not torsion, unless your tee has an elbow on it?

A sketch is always good to see.

Item 3 - It just becomes a beam bending calculation to establish bending moment at any particular location using what is hopefully a uniformly distributed force on the beam (pipe)

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[1503-44]

T there will be torsion somewhere. Whichever leg goes in the water will bend itself and twist the member its attached to. Probably can't be avoided. Make it all out of pipe for max strength in torsion, and bending too for that matter.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[1503-44]

Actually I think Cd for pipe is 0.8 you'd better check that number too.

A black swan to a turkey is a white swan to the butcher ... and to Boeing.

 

[bimr]

There are two components, the drag on the object and the drag through the object.

The drag on the object can be estimated with the calculator:

Calculator

The drag through the object is the headloss through the pipe. That can be estimated with the Darcy–Weisbach equation.

 

[1503-44]

Is there internal flow?

A black swan to a turkey is a white swan to the butcher ... and to Boeing.