Fwd: [ODE] what a drag

[Francisco Jesús Martínez Serrano]

El Viernes, 4 abr, 2003, a las 21:29 Europe/Madrid, Nate W escribió:

> However, if operating in a "universe" with uniform viscosity (if that's
> the right word - I mean no air/water or air/vacuum boundaries), it 
> should
> be possible to approximage aerodynamic effects with just one function 
> call
> right after the collision step.  Let's call it fluid drag just to be
> general...
>
> The one function would iterate the list of ODE bodies, get their
> velocities and geoms, compute the cross-section area of the geom as 
> viewed
> from the velocity direction, and apply a force proportional to the 
> cross
> section area and the velocity vector.  Easy, right?  :-)
>
> The part about computing the cross section sounds hard, unless the 
> geoms
> are all spheres.  Anyone know of a simple and/or fast way to do that 
> for
> boxes at arbitrary orientations?  Cylinders?

The thesis of Scott McMillan has some info on computing approximate 
effects of viscous drag. It's implemented in dynamechs.

http://dynamechs.sf.net

The thesis is also on that site.

Cheers.