If I had Anni and was concerned about noise, I would try Noctua. I think the smallest they make is 40mm, but it may be 30mm.
Their fans are designed to be hung at different angles, (as most PC CPU cooler fans are). I have two on my CPU cooler and they blow air out of the back of the PC. CPU coolers can also be fitted to blow upwards, as apposed to how I have mine set. Meaning they can be hung.
However Noctua's fans have one advantage over other fans. They are designed with turbulence reduction. Menaing less noise created by the fan as it moves air.
We'll never get rid of air-whoosh noise because air makes noise when moving. However getting the best fan for cooling, aligned with turbulence control, is win-win. As I said before they cool better than most fans, so can run quieter based on that too.
Plus Noctua have an excellent exchange policy for the instance where you get a noisy one. Contact them with proof of purchase and your issue, and they post you a replacement. They have an excellent policy overall. E.g. if your CPU cooler is going to be used on a new motherboard. You may need a new backet to attach the cooler to the new motherboard. The CPU socket will likely be different from one generation of CPUs and motherboards, to the next. You tell them of this (with proof of purcahase), and they send you a new bracket free. Then you can attach your existing cooler to the new board. Their idea is that this saves waste - meaning from an eclogical point of view. Can't really go wrong with them.