Differences between NOUN + NOUN vs ADJ + NOUN!!!

Hello everybody!
I’m very confused when I use NOUN + NOUN vs ADJ + NOUN.
Specifically, I don’t understand differences between “industrial expert” and “industry expert”. In my teacher’s opinion, “industry expert” is right; and the result of “industry expert” on Google is so bigger than the result of “industrial expert”.
Could you explain to me why that?
Thank you a lot :slight_smile: