The air tries to follow the curvature but at some point at the rear of the helmet, this becomes too difficult and the air will detach or separate from the surface.
On round objects like a helmet, this location of separation can vary over time and can move upstream & downstream at a high frequency.
This, in turn, causes an oscillation in the force exerted on the head of the rider. This can cause fatigue as well as vibrations that reduce the focus of the rider's vision.
By fixing the separation location, by forcing the air to detach at a specific location, this oscillation in force can be strongly reduced.
The MotoFin does exactly that: the sharp edge at the rear end will force the flow to detach, indicated by the low surface friction area (blue) that follows downstream of this geometry (low friction typically indicates a detached flow). In addition, it is likely that the MotoFin can also provide a stabilizing effect for the yaw rotation (left-right rotation) of the helmet, just like the long vertical fins on F1 cars. In conclusion, MotoFin can help provide stability benefits at higher speeds to almost all riders / drivers in multiple action sport disciplines. With our crushable patented design you can achieve this all while not interfering with helmet safety. Data provided by AirShaper.