In the diagram below, A is a disk and C is a pipe, the A and C combination is a nozzle, B is a board. As long as B is close enough to A, with the air from the D, B will be sucked and will not fall down. Why is this the case?
I don't think this phenomenon can be explained by Bernoulli's law, because the air in the gap expands. Because the air moves outward, the radius of the nozzle is larger, and the volume of the gap between the A and the B passing through the air is proportional to the square of the radius. Low pressure due to expansion. B doesn't fall because of low pressure. This video shows this.