Lift production using differential cavity ventilation on a symmetric hydrofoil

Cavitation near lifting surfaces is typically viewed as a problem to be mitigated, because local cavitation on highly loaded surfaces both reduces the lift and invites damage near the point of cavity collapse. However, this loss of lift indicates that it may be possible to produce controllable forces by artificially inducing a cavity on one side of a symmetric hydrofoil by using ventilation gas. Experiments have been performed in order to test this idea, and the results are in agreement with the working theory. The produced forces are robust, equivalent to 4° angle-of-attack using a NACA0009 cross-section. Time-dependent and hysteretic features of the system have also been identified.