Recommended books about vorticity

Vorticity and Incompressible Flow - Andrew J. Majda, New York University Andrea L. Bertozzi, Duke University, North Carolina

The above one is pretty much for beginners, with a good mathematical background it is good for you.

After reading this you may also read the book 'Vorticity and Vortex Dynamics by Jie-Zhi Wu, Hui-Yang Ma, Ming-De Zhou', it's not much introductory. It is based the old experiments and research done.