Integrate function over a closed surface

Hi

I need to perform an integral over the surface of a sphere/circle (haven't decided on 2d vs 3d simulation yet) of the force due to an inhomogeneous and time-varying scalar pressure field to calculate the instantaneous net pressure force on the sphere.

So this will require integrating dF = P(r)dA across the surface, where P(r) is an arbitrary function of position from an external origin (a source of expanding gas)

Can this be done directly or would I have to divide the surface into triangles and approximate the pressure on each before summing? If the latter how would I go about this

Cheers

[Torsten]

On the surface of a shere, r is constant. So why is P a function of radius ?

Best wishes

Torsten.

[LW942]

Sorry, the sphere is a particle near a source of gas. This gas source is what generates P(r), so P(r) is a function of position from the origin

[Torsten]

This can be done directly if you can supply P(r) for each value of r.

Use spherical coordinates and MATLAB's "integral2" for the 3d-case.

Best wishes

Torsten.