In Star Trek (2009), Ambassador Spock's ship The Jellyfish has the distinctive feature of having the rings rotating around it constantly. What was the point of this (in-universe) - it's the first time that I've seen anything like that in Star Trek before, and it's not to increase speed (as it has a maximum of warp 8 according to Memory Alpha)?
In Abrams-verse canon
There is no official purpose to the spinning design of the tail section of the Jellyfish starship.
The Jellyfish was designed with trans-metaphasic shielding. A shielding capacity making it possible for the ship to survive moving into the main body of a star. This may explain why the tail section rotated to enhance and stabilize the expanded metaphasic shielding capacity which protected the warp engine of the starship.
In canon: From notes found on Memory Alpha