The underwater high-speed vehicle surfaces are enveloped by cavity entirely or mostly, which reduces skinfrictiondrag 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 engineering project, negative skinfriction is the drag force that will reduce the vertical bearing capacity and cause differential settlement of the structure.