Depends on the festival, but in general, sure. If there are girls there (and they are not behind velvet ropes, barricades or up on stages), you probably have a chance of meeting them. Then what?

Regardless, the reason for going to a festival is to attend the festival itself and presumably have fun. Going only “to meet girls” is missing the point and setting yourself up for disappointment (and probably coming off a little creepy in the process). If you don’t like festivals, you can meet girls in far less expensive and noisy places, too.