General:
* Eddies
* Vortices
* Whirlpools
* Spirals
* Curls
* Twirls
* Whorls
* Undulations
* Meanders
More specific:
* Volute (for a spiral-shaped scroll)
* Swell (for waves or rising movement)
* Ripple (for small waves or undulations)
* Concentric circles (for circular swirls)
* Marbling (for swirls in a mixture of liquids)
* Whirlwind (for swirling air)
* Galaxy (for large cosmic swirls)
Figurative:
* Gyrations
* Revolving
* Circuitous
* Circular
* Roundabout
The best word to use will depend on the specific context and the type of swirl you are describing.