737 fan section. The blades slide individually into the hub and reside with a bit of a gap. As the de-ice and other seasonal crap fluids seep/fling out of a spinning hub, it dries quickly on the blade while at power. We see the pattern curve as it slides out, where not only it’s at higher velocity, but the fan also starts to load up and carve the air for thrust. The fluid changes direction from the air flow instead of just sliding out centrifugally. Patterns in physics are cool.