Gayle is spot on....next time, if you catch her eye, just say hello, or whatever version you prefer of the same greeting (try to avoid 'sup'...pretty much a conversation killer lol jk)

And yes, she may think you're married, but if you don't wear a ring--yes yes I know lots of married men don't, but far more do because their wives insist--she's probably noticed that.

I guess the best thing is to smile and say hi. If she's seen you there often enough (which I inferred by your post) it will seem more natural if you DO say hi, than if you don't.

Good luck to you