Try these: 1. Test the wind force so it isn't too strong, hair shouldn't become a straight plank. 2. Check hair bend resistance (in hair room) so it isn't too weak, there has to be some resistance  against the wind to show effect, start at 0.85 and see what happens. 3. Make sure you run the 'Recalculate dynamics' (menu - animation - recalculate dynamics - all hair) for the hair to be calculated against the wind for every frame.

Hope this helps.

Oh, and it can't become wavy unless the model moves or the hair is wavy from the start.