P-trap different shapes

[Holeshot]

Hello, I see different p-trap shapes. Some are like a perfect U shape and some have a tighter radius on one side. Is that to water turbulence to slow down the flow or prevent siphoning the water out of the trap? Laundry p-traps would have more down force than bathtubs.

Are certain p-trap shapes better for bathtubs and laundry?

 

[Reach4]

If the input to the trap is more straight up and down that is a little better, but not a lot better.

See #27 on https://terrylove.com/forums/index.php?threads/sink-drain-too-high-help.66822/page-2#post-497326