I believe realistic fluid dynamics in the scale of a full breaking wave is unheard of for real time graphics, there's just no way to do it in 30-60FPS (I could be wrong tho!)

What I do instead is to transform a procedural plane mesh into wave-like geometry. For added realism, I base this transformation on bathymetry data (ocean floor height), so you can get left/right breaking waves, different breaking sessions, etc, just by defining different heightmaps.