Experimental Evaluation of the Performance of the TAP-1 Supercavitating Hydrofoil Model at 80 Knots.

摘要

Experimental results are presented for a model of the TAP-1supercavitating hydrofoil system in its high-speeds mode of operation. To realistically simulate the ventilation air demand of the prototype craft,the model was examined at full water speeds using cavitation number scaling. The experiments were conducted in the NASA Aircraft Landing Dynamics Facility,an outdoor free-running towing carriage. Unsteady loads in lift,drag,side force,and pitching moment were continuously recorded on analog tape and were then time averaged. The foil (chordline) angle of attack ranged from 2.4to 10.4degrees at 80knots. The strut side force in yaw developed by the foil system and by the basic parabolic strut only was recorded for speeds of 50, 70,and 80knots. The maximum strut sideslip angle at 80knots before sudden side ventilation was 3 1/4degrees. The cavity air demand increased linearly with water speed (or Froude number) over the range of speeds examined. While the strut spray wedges were absolutely necessary to achieve full ventilation,their presence added only about 10percent to the drag. The spanwise twist of the model was successful in maintaining the cavity out to the wing tips at low angles of attack,but failed to recreate the sectional loading. The maximum lift-to-drag ratio measured in full cavity flow was 6.6. No vortex shedding or leading edge vibrations were observed. (Author)