# Wind pressure force for complex profiles ?

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1. Nov 25, 2014

### Aleksej

How to calculate the force of wind pressure, for example for the surface tilted at 45 degrees?

I need to find some serious work related to the wind pressure force calculated for different 3D shapes affected by wind from different angles.

Can somebody recommend me the good names, keywords and sites for this?

2. Nov 25, 2014

### Staff: Mentor

There are some standards that are based on simple calculations, for instance ISO 4302. If you need something more sofisticated, I don't know if there are other ways of doing it than simulations.

I guess that "wind load" is the keyword here.

3. Nov 25, 2014

### Aleksej

Thank you very much, I will try to use it but they consider "force in the direction of the wind", I need more something like full force.

4. Nov 25, 2014

### Staff: Mentor

If you're talking about the ISO standard, they are considering full force. That's the point of the exercise: figuring out the maximum load on a structure in order to design it such that it can resist in strong winds.

5. Nov 30, 2014

### Aleksej

You see what they write:

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For most complete and part structures, and individual members used in crane structures, the wind load, F, in kilonewtons, is calculated from the formula

F = A * p * Cf

A is the effective frontal area of the part under consideration, in square metres, i.e. the solid area projection on to a plane perpendicular to the wind direction;

p is the wind pressure corresponding to appropriate design condition, in kilonewtons per square metre;

Cf is the force coefficient in the direction of the wind, for the part under consideration (see clause 5).

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Their coefficient is "in the direction of the wind".

6. Dec 1, 2014

### Staff: Mentor

Yes, the force coefficient, which depends on the geometry of the beams, is calculated for face-on load. Then, in section 5.4, the equation is modified to take into account wind at an angle:
$$F = A p C_\mathrm{f} \sin^2 \theta$$