In England, the beaches can be windy. I have seen people put up a "wind shield" like this.
I haven't seen people use this in America or Europe, but I haven't been to many beaches there.
I'd call this wind shield, simply because it shields the wind. But in America, windshield means the frontal glass of a car.
Is there a more proper name for this in British English, American English and other English (South African, Australian, etc)?