亜音速パラシュートの動的荷重特性

抄録

This paper concerns with the results of an experimental study on dynamic load characteristics in parachute inflation at a subsonic speed. The unsteady drag of the parachutes in the process of inflation is measured in a wind tunnel at M=0.2, and the opening shock load is examined in detail with emphasis on the effects of porosity and size of the models. It is shown that the circular vents near the edge of the canopy are more effective than the slit vents to reduce the opening shock load without considerable decrease of drag in the steady-state. Detailed examination reveals that the model geometry as well as descending speeds has no serious influence on the coefficients of the opening shock load C_m and the opening time C_t, if both C_m and C_t are defined by use of the effective references calculated from the concept of an equivalent parachute, which has a circular plane canopy with the reduced area obtainable by subtracting porous area from the geometric one.