Numerical Study of Effect of Vent Ratio on Drag Coefficient of Parachutes in Steady Conditions

Study of parachutes is very important in aerospace industry. In this research, the effect of various Reynolds numbers on a parachute with a vent and without a vent at the top on drag coefficient in a steady and turbulent condition is studied. After a complete research on an efficient grid study, the drag coefficients are calculated numerically. The Reynolds number is varied from 39000 to 390000 (5 m/s to 50 m/s). It is found that, for a parachute without a vent at the top, as the Reynolds number is increased from 39000 to approximately 230000, the drag coefficient is decreased from about 2.15 to 1.6, and then as the Reynolds number is increased to 390000, the drag coefficient stayed constant. As the vent ratio of the parachute is increased from zero to 5, the drag coefficient was increased and for further increase of the vent ratio, the drag coefficient decreased, but the general variation of drag coefficient was the same as of same parachute with no vent.