Streamline of bubbles around a semi-hemispherical ceiling rock.

The radius of the ceiling rock is R. The ceiling rock is completely immersed in water. Bubbles released by the divers create a flow around the rock. Point “A” represent the stagnation point on the ceiling rock whereas “B” represents a point at the same depth where there is no ceiling rock. The bubble terminal velocity is W_B. Because of the bubble flow, there is an excess pressure exerted on the ceiling causing a drag on the rock.