The underwater high-speed vehicle surfaces are enveloped by cavity entirely or mostly, which reduces skin friction drag and allows the vehicle to obtain high speed.
水下超高速航行体的全部或大部分表面被空泡包裹，使其阻力显著降低而达到高速航行的目的。
2
In the cavity flow mode, the drag of the cylinder was dramatically reduced by the upstream rod.