Analysis of a wind vane/weather vane

[james6008]

Hi

I am trying to create a model to simulate the motion of a weather vane. It basically looks at the wind direction and as the wind direction changes, the objects responds by trying to align itself parallel to the wind.

First of all I am looking at the force perpendicular to the pivot point of the vane. This force increases as there is a greater change in the wind direction.

I am using F= 0.5*rho*(v^2)*A to calculate the force
where v = velocity (wind speed) and A=area of the vane

I am using this force and resolving it for an angle (theta) which is the change of wind direction. I am then calculating the turning moment of the object by using this resolved force and the distance from the pivot point. This turning moment governs the respond of the object to the change in the wind direction.

I am stuck right now because I need to try and incorporate the mass of the object in this model. I am not sure where is the right place to include this and what equation do I need to use?

Can you please help/guide me in the right direction?

Thank you

 

[Baluncore]

http://en.wikipedia.org/wiki/Moment_of_inertia

 

[james6008]

Hi

Thanks for this. I've had a look at this before but I got lost in the maths.

I am already calculating the Moment which is Force*distance from the pivot

The Moment of inertia is just mass m * square of its perpendicular distance r

How will I link both the first equation and second one? Because I want it to consider the force that has been applied to move the weather vane in the direction of the wind against the actual mass of the body.

 

[ravi biradar]

please tel me the detailed calculation of wind vane...please post it soon ...

 

[Humphrey Kirk]

You may create a model and its mesh with Hypermesh or Gambit, then import the mesh to the Fluent unsing the finite element method to calculate.