Looking through photos of Apollo CM capsules after reentry, I was trying to have a feel for how the heat was distributed on the sides of the capsule. By the look of surviving patches of Mylar tape and not melted aluminum EVA handles the reentry temperature on the side of the capsule doesn't seem to be too high. Certainly not high enough to charr the ablative material on the side surface and melt the handles. But then I paid attention to interesting pattern of charred ablative material around the RCS thrusters (appeared to be the roll thrusters that would be used to "steer" and manipulate lift during reentry).
This one from Apollo 11:
image from http://www.collectspace.com/review/apollo11_cm_radiationlabels01-lg.jpg
Apollo 13: image from https://www.nasa.gov/sites/default/files/thumbnails/image/capsule_.jpg
Apollo 12: image from https://www.nasa.gov/sites/default/files/thumbnails/image/s69-22271.jpg
Apollo 8: image from https://en.wikipedia.org/wiki/Apollo_8#/media/File:Ap8-S68-56310.jpg
Question: Why this shape of the pattern?
Given it is only around the thrusters (and not elsewhere on circumference of the conical part) it probably means some interesting reaction of thruster exit gas with the air flow (and/or the shock wave) around circumference of the main shield at the bottom. But why is it on both sides (above and below) of the thrusters? One would think that velocity of incoming air would be way higher than what comes out of the thrusters and push the exhaust upwards, that's why I can't really understand why the shield is charred immediately below the thrusters as well.