
(Resistance decrease in nature - a bad translation of the heading from a univerity in Sweden), but there is some links in the end that may be helpful. It talks about friction according to form and friction increase when flow is to leave the body. It says something about delphins that have small "ridges (fåror in Swedish), don't know the word" that makes the animal to feel the preassure and then they can change the hight/depth of thoose "ridges" to decrease friction.

oops, just to read then. I did not manage to get it to work but after some more tries it did.