Mazyar Dawoodian - Sama Technical and Vocational training college, Islamic Azad University, Mahabad branch, Mahabad, Iran
Abdolrahman Dadvand - Department of Mechanical Engineering, Urmia University of Technology, Urmia, Iran
Amir Hassanzadeh - Sama Technical and Vocational training college, Islamic Azad University, Mahabad branch, Mahabad, Iran

In this research, the flow past a parachute with and without a vent hole at the top is studied both experimentally and numerically. The effects of Reynolds number and vent ratio on the flow behaviour as well as on the drag coefficient are examined. The experiments were carried out under free flow conditions. In the numerical simulations, the flow was considered as unsteady and turbulent and was modelled using the standard k-ε turbulence model. The experimental results reveal good agreement with the numerical ones. In both the experiments and numerical simulations, the Reynolds number was varied from ۸۵۵۳۹ to ۳۵۷۲۵۰ and the vent ratio was increased from zero to ۲۰%. The results show that the drag coefficient decreases by increasing the Reynolds number for all the cases tested. In addition, it was found that at low and high Reynolds numbers, the parachutes respectively with ۴% vent ratio and without vent are deemed more efficient. One important result of the present work is related to the effect of vent ratio on the stability of the parachute.

Parachute; Experimental investigation; CFD analysis; Drag coefficient; Vent ratio