# Analysis of a wind vane/weather vane

• james6008
In summary, the conversation discusses creating a model to simulate the motion of a weather vane in response to wind direction changes. The force perpendicular to the pivot point of the vane is calculated using F=0.5*rho*(v^2)*A, where v is the wind speed and A is the vane's area. This force is then resolved for an angle (theta) and used to calculate the turning moment of the object. However, the conversation also mentions the need to incorporate the mass of the object in the model, and questions arise about where and how to include this in the calculation. The conversation ends with a suggestion to use a finite element method to calculate the detailed wind vane model.
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?

Thank you

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.

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

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.

## 1. How does a wind vane/weather vane work?

A wind vane/weather vane works by utilizing a pointer or arrow that is balanced on a central axis. As wind blows against the pointer, it will rotate to point in the direction from which the wind is coming. This allows you to determine the direction of the wind.

## 2. What is the purpose of a wind vane/weather vane?

The primary purpose of a wind vane/weather vane is to determine the direction of the wind. It is often used in weather forecasting, as well as for indicating wind direction for activities such as sailing or flying.

## 3. How accurate is a wind vane/weather vane?

The accuracy of a wind vane/weather vane depends on various factors such as design, installation, and maintenance. However, most wind vanes are designed to accurately point in the direction of the wind within a few degrees.

## 4. Can a wind vane/weather vane measure wind speed?

No, a wind vane/weather vane is not designed to measure wind speed. Its primary function is to indicate wind direction. To measure wind speed, you would need an anemometer, which is a different meteorological instrument.

## 5. What are the different types of wind vanes/weather vanes?

There are several types of wind vanes/weather vanes, including the traditional arrow-shaped vane, the propeller vane, and the tail vane. Each type has its own unique design and can be used for different purposes, such as measuring wind direction at different heights.

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