Self-actuating, foldable obstacle system on hydraulic lifting bodies

摘要

A foldable obstacle system is provided on a hydraulic lifting body to alleviate cloud cavitation and so to reduce noise and surface erosion that might otherwise result from unsteady sheet cavitation and a re-entrant jet produced thereby. The system includes one or more foldable obstacle devices or plates, each of which is movable between a closed position at the surface of the body and an open position away from the body. When a re-entrant jet occurs, the jet acts to lift the plates and rotate them into the open position in which they block the re-entrant jet so as to reduce or prevent cloud cavitation. When cavitation does not occur, the normal fluid flow over the body acts to close and keep closed the obstacle devices or plates so that they do not interfere with the normal fluid flow.