Our customer is responsible for design and development of parachutes in India and wanted to develop acquire new simulation and design capabilities. They wanted to design and develop a software system that will take care of design of conventional parachutes. The software should be able to predict shape of the inflated parachute using a fluid structure interaction (FSI) code. Aerodynamic characteristics were to be predicted for inflated shape module along with the structural strength for the load cases. Both the aerodynamics and structural module were to be tightly coupled to take care of the effects of shape change.
Parametric software was developed to generate the shapes and surface mesh for the parachutes automatically just by filling a form. Surface mesh is generated with proper densities at the edges. After inflation, incompressible solver was developed to simulate the porous material of parachutes. Output from aerodynamic module was fed to FEM code that in turn gave new shape and hence new aerodynamics. Solver iterated till a steady state was reached.
Figure shows the inflated shape of the slotted parachute that has also been tested in the wind tunnel and found to be matching well. Velocity profile and vectors are shown. All the modules of generation of parachute shape by inflation, CFD and FEM are tightly coupled. Entire simulation suite has been validated for T-10 parachute. The software is developed as generic so as to simulate not just parachutes; rather any inflatable structure subjected to pressure and gravitational forces.