### Abstract

In the near future, large ram-air parachutes are expected to provide the capability of delivering 21 ton pay loads from altitudes as high as 25,000 ft. In development and test and evaluation of these parachutes the size of the parachute needed and the deployment stages involved make high-performance computing (HPC) simulations a desirable alternative to costly airdrop tests. Although computational simulations based on realistic, 3D, time-dependent models will continue to be a major computational challenge, advanced finite element simulation techniques recently developed for this purpose and the execution of these techniques on HPC platforms are significant steps in the direction to meet this challenge. In this paper, two approaches for analysis of the inflation and gliding of ram-air parachutes are presented. In one of the approaches the point mass flight mechanics equations are solved with the time-varying drag and lift areas obtained from empirical data. This approach is limited to parachutes with similar configurations to those for which data are available. The other approach is 3D finite element computations based on the Navier-Stokes equations governing the airflow around the parachute canopy and Newton's law of motion governing the 3D dynamics of the canopy, with the forces acting on the canopy calculated from the simulated flow field. At the earlier stages of canopy inflation the parachute is modelled as an expanding box, whereas at the later stages, as it expands, the box transforms to a parafoil and glides. These finite element computations are carried out on the massively parallel supercomputers CRAY T3D and Thinking Machines CM-5, typically with millions of coupled, non-linear finite element equations solved simultaneously at every time step or pseudo-time step of the simulation.

Original language | English |
---|---|

Pages (from-to) | 1353-1369 |

Number of pages | 17 |

Journal | International Journal for Numerical Methods in Fluids |

Volume | 24 |

Issue number | 12 |

Publication status | Published - 1997 Jun 30 |

Externally published | Yes |

### Fingerprint

### Keywords

- 3D flow simulations
- Parachutes
- Parallel computations

### ASJC Scopus subject areas

- Computational Mechanics
- Mechanics of Materials
- Mechanical Engineering
- Computer Science Applications
- Applied Mathematics

### Cite this

*International Journal for Numerical Methods in Fluids*,

*24*(12), 1353-1369.

**Parallel finite element simulation of large ram-air parachutes.** / Kalro, V.; Aliabadi, S.; Garrard, W.; Tezduyar, Tayfun E.; Mittal, S.; Stein, K.

Research output: Contribution to journal › Article

*International Journal for Numerical Methods in Fluids*, vol. 24, no. 12, pp. 1353-1369.

}

TY - JOUR

T1 - Parallel finite element simulation of large ram-air parachutes

AU - Kalro, V.

AU - Aliabadi, S.

AU - Garrard, W.

AU - Tezduyar, Tayfun E.

AU - Mittal, S.

AU - Stein, K.

PY - 1997/6/30

Y1 - 1997/6/30

N2 - In the near future, large ram-air parachutes are expected to provide the capability of delivering 21 ton pay loads from altitudes as high as 25,000 ft. In development and test and evaluation of these parachutes the size of the parachute needed and the deployment stages involved make high-performance computing (HPC) simulations a desirable alternative to costly airdrop tests. Although computational simulations based on realistic, 3D, time-dependent models will continue to be a major computational challenge, advanced finite element simulation techniques recently developed for this purpose and the execution of these techniques on HPC platforms are significant steps in the direction to meet this challenge. In this paper, two approaches for analysis of the inflation and gliding of ram-air parachutes are presented. In one of the approaches the point mass flight mechanics equations are solved with the time-varying drag and lift areas obtained from empirical data. This approach is limited to parachutes with similar configurations to those for which data are available. The other approach is 3D finite element computations based on the Navier-Stokes equations governing the airflow around the parachute canopy and Newton's law of motion governing the 3D dynamics of the canopy, with the forces acting on the canopy calculated from the simulated flow field. At the earlier stages of canopy inflation the parachute is modelled as an expanding box, whereas at the later stages, as it expands, the box transforms to a parafoil and glides. These finite element computations are carried out on the massively parallel supercomputers CRAY T3D and Thinking Machines CM-5, typically with millions of coupled, non-linear finite element equations solved simultaneously at every time step or pseudo-time step of the simulation.

AB - In the near future, large ram-air parachutes are expected to provide the capability of delivering 21 ton pay loads from altitudes as high as 25,000 ft. In development and test and evaluation of these parachutes the size of the parachute needed and the deployment stages involved make high-performance computing (HPC) simulations a desirable alternative to costly airdrop tests. Although computational simulations based on realistic, 3D, time-dependent models will continue to be a major computational challenge, advanced finite element simulation techniques recently developed for this purpose and the execution of these techniques on HPC platforms are significant steps in the direction to meet this challenge. In this paper, two approaches for analysis of the inflation and gliding of ram-air parachutes are presented. In one of the approaches the point mass flight mechanics equations are solved with the time-varying drag and lift areas obtained from empirical data. This approach is limited to parachutes with similar configurations to those for which data are available. The other approach is 3D finite element computations based on the Navier-Stokes equations governing the airflow around the parachute canopy and Newton's law of motion governing the 3D dynamics of the canopy, with the forces acting on the canopy calculated from the simulated flow field. At the earlier stages of canopy inflation the parachute is modelled as an expanding box, whereas at the later stages, as it expands, the box transforms to a parafoil and glides. These finite element computations are carried out on the massively parallel supercomputers CRAY T3D and Thinking Machines CM-5, typically with millions of coupled, non-linear finite element equations solved simultaneously at every time step or pseudo-time step of the simulation.

KW - 3D flow simulations

KW - Parachutes

KW - Parallel computations

UR - http://www.scopus.com/inward/record.url?scp=0031172028&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0031172028&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0031172028

VL - 24

SP - 1353

EP - 1369

JO - International Journal for Numerical Methods in Fluids

JF - International Journal for Numerical Methods in Fluids

SN - 0271-2091

IS - 12

ER -