Noctua NH-U12S CPU Cooler
The NF-F12 PWM fan is a great match for this cooler as it is larger than the fins are tall, and allows this fan to cover most of that fin area. You will also notice that there is a 4-pin connection for this fan and the curve of the pipes as they are staggered into the fins.
From the side you can see that the fan is held in place with wire fan clips that lock into grooves in the cooler. In between where one can clip on the front or the back, the fins have been closed off to better utilize the airflow from the fan or fans.
Without a fan on this side you can get some idea of the grooves and teeth in the leading edges of the fins to break up the air flow. You can also see if you look closely that the pipes are spaced very evenly on both sides with two on the outside, one in the middle, and then two again closest to the middle of the fin stack.
From side to side there are no differences to describe. There is still the wire clip holding this side of the fan on, and this side is closed off just as the other side is.
Each fin in the stack has the Noctua Name on logo on them, not only for show, but as something to break up the air flow too. You can also get a much better idea of the thinner center section and the teeth that allows the fan to maximize its air flow and pressure.
Looking at the fins from this angle you lose a bit of perspective on the curve across the entire fin, but rather here you see more of the grooves and how they play their part under where 75% of the fans air flow will pass over them.