The Collaborative International Dictionary of English v.0.48:

Swirl \Swirl\, v. t. & i. [imp. & p. p. Swirled; p. pr. & vb.
   n. Swirling.] [Akin to Norw. svirla to whirl, freq. of
   sverra to whirl, Dan. svirre, G. schwirren to whiz, to buzz.
   [root]177. See Swarm, n.]
   To whirl, or cause to whirl, as in an eddy. "The river
   swirled along." --C. Kingsley.
   [1913 Webster]