I searched the forum and couldn’t find anything about this topic. If there is already, feel free to flag and close as a duplicate.
Looking at the 787 anyone will notice that the engine covers are serrated. The article below calls them ‘chevrons’.
I always wondered, why why why. Turns out, it all has to do with noise abatement. Interesting article. Never knew that NASA had a hand in this design.
Just thought the IF community might be wondering the same thing!