I use the sous vide function on my instant pot sometimes. Mostly for infusing oils, but also for meat sometimes.
Discussion
How does the water circulate in an Instant Pot?
By convection primarily but because it’s not boiling you don’t risk the bottom burning typically. However if you’re cooking a very thick liquid like tomato sauce I recommend getting it to a boil while stirring first and then covering it for pressure cooking to avoid burning bottom.
I mean when covered and using the pressure cooking aspect it doesn’t boil. It’ll obviously boil if uncovered.
I don't think it does. Just keeps it at the set temperature.