Basic particle & "airflow" animations

I agree with Mike - simply fake the hell out of it using moving fractal noises and distortion effects. Even Foam and Particle Playground may already be way too complicated, as it takes lots of experience to massage the parameter maps. If you still feel like spending money, then Trapcode Form might be more appropriate than Particular, BTW.

Mylenium

Flowing particles along a path isn't super easy in Ae - with default plugins at least - but there is a default effect that can do it - the 'Foam' plugin. It's a pretty complex effect, but the key element for this requirement is that it supports a 'flow map' - a grayscale image that can direct the flow of the generated foam. You can also customise the foam however you wish by creating a custom sprite.

And a few further options:

Try the old 'particle playground' effect using the 'wall' option - this requires you to draw a closed shape mask - ie the area of particle flow.

Another approach would just be to create a simple straight directional particle flow using particle world - precomp that and then use mesh warp or liquify or something else to distort the flow path into the shape you require.

Hello maybe you can use Particle World effects and perosonalize the parameters.
Its very useful.

Best regards