Why is it when a jet engine spools up, you sometimes see a cloud in the turbine?

first of im bit of newb when comes aircraft engines. anyway, can see on rainy days how water creates cloud in engine, on clear sunny days? told me because airflow goes supersonic. wouldnt make plane go supersonic? know commercial aircraft cant break sound barrier. im confused.

first of im bit of newb when comes aircraft engines. anyway, can see on rainy days how water creates cloud in engine, on clear sunny days? told me because airflow goes supersonic. wouldnt make plane go supersonic? know commercial aircraft cant...

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