We are missing a bit of context here, but as I understand, It is a way to insist there are some forces "actives", not just any type of force.

I suppose several types of forces were mentioned earlier in the text/speech, then "active" ones and it’s a way to insist on those latter ones being present in this flux perpétuel.

One could have also said :

• (…), il y bien des forces "actives" .
• (…), il y a effectivement des forces "actives".

I must say it’s a "spoken style" sentence, and depending on the intonation of speaker, it could also imply there are a lot of active forces.

Compared to the original sentence, a non-pleonastic variant looks like a plain boring description to me (physics school book’s style) :

Au sein de ce flux perpétuel, il y a des forces "actives".