Suppression of Pressure Oscillation in Supersonic Parachute Model Using a Ring

A method for suppressing the pressure oscillation of supersonic parachutes is proposed in this study. This method placed a ring with a triangular or circular cross section in front of the canopy of a parachute. A rigid metal canopy was used in supersonic wind tunnel tests. Hard piano wires with a diameter of 0.8 mm were used as suspension lines and a riser to connect a fore body and the canopy. In the wind tunnel test without a ring, pressure oscillation with the accompanying time variation of the shock wave structure was observed at Mach 3.0. A detached shock wave oscillated back and forth because it interfered with the boundary layer developed on the suspension lines. A large-amplitude pressure oscillation was observed with the pressure sensor placed at the center of the canopy. The large pressure oscillation was suppressed using a ring. The time variation of the shockwave structure suppressed. The amplitude of the pressure with the sensor reduced to 1/2 of that without a ring. We also found that the location and cross-sectional shape of the ring affects the flow around the canopy.