Ventilated cavity test of a 3-inch diameter streamlined nose

A ventilated cavity test of a 3 inch diameter streamlined nose has been conducted in the 48 inch water tunnel. Tests were conducted at 10, 20, 30 and 40 fps for dimensionless cavity lengths (L sub C/D) from approximately 1 to 4. The cavitating flow was documented by video tape and still photography. The purpose of the test was threefold namely (1) to approximate the ventilation flow rate coefficient (C sub Q) (2) to observe the stability of the pressure control system as gas was added to the flow, and (3) to observe the approximate boundary between the twin vortex regime and reentrant jet regime. The major results are (1) the ventilation flow rate coefficient is approximately 30% greater than that estimated for a quarter caliber ogive nose, (2) the pressure control system is stable and (3) the twin vortex regime is primarily confined to velocities of 10 fps and less for the gas flow rates employed in this investigation.