Kana Yoshida1,2, Reha Avsar3, Aaron Hartmann3, Taro Kanai4, Takafumi Sasaki4, Kenji Takizawa4 and Tayfun E. Tezduyar3

1Department of Mechanical Engineering, Tottori University, Tottori, Japan. 2TOMODACHI STEM Program @ Rice University, Houston, Texas, USA.3Mechanical Engineering, Rice University, Houston, Texas, USA. 4Department of Modern Mechanical Engineering, Waseda University, Tokyo, Japan.

b13t1064b@edu.tottori-u.ac.jp

Structural Mechanics Computation of the Orion Spacecraft

Drogue Parachute in Compressible-Flow Regime

Methods and Conditions

Base Computation (Case 0)

Pressure Dependence

Time Resolution Effect

Orion spacecraft parachute sequence From NASA site

Drogue parachutes

Compressible flow

Main parachutes

Incompressible flow

Background- Orion Drogue Parachute

Drop test From NASA site

Cost is about a million dollar for

each test.

Wind-tunnel test From NASA site

Scaling challenge due to coupling

between the canopy deformation

and the airflow.

- Field Tests

Computational analysis

can serve as a practical alternative.

• How the solution and the solution process vary

→ Pressure : Parachute diameter and vertical position change.

→ Dt : Computing time can be reduced by increasing Dt.→ η : The settled shapes are close, but η =140 s-1 leaves out movement

details, which are actually not needed.

• Larger time-step size?

→ With larger Dt, we can reach the settled shape sooner, with

almost the same shape as in Case 0, but with less computing time.

References[1] K. Takizawa, T.E. Tezduyar, and R. Kolesar, “FSI modeling of the

Orion spacecraft drogue parachutes, Computational Mechanics,

Vol. 55, pp.1167-1179, 2015.

[2] K. Takizawa, T.E. Tezduyar, and T. Kanai, “Porosity models and

computational methods for compressible-flow aerodynamics of

parachutes with geometric porosity”, Mathematical Models and Methodsin Applied Sciences, DOI: 10.1142/S0218202517500166, 2017.

This research was conducted as part of the 2017 TOMODACHI STEM @ Rice

University Program which is funded by a grant from the TOMODACHI Initiative, a

program of the US–Japan Council. For more information on TOMODACHI program,

see http://tomodachistem.rice.edu/. We are grateful to Tatsuya Tanaka for using

some of the background material from his poster.

- Governing Equations

Structural mechanics equations

- Spatial Discretization

Finite element method

Parachute configuration [1]

Mach number 0.5

Altitude (ft) 35,000

Base conditions

• Case 3 parachute shape settles sooner than Case 0.

• Case 3 parachute shape is almost the same as it was in Case 0.

• Case 4 parachute shape settles even sooner than Case 3.

• Case 4 parachute shape is almost the same as it was in Case 0.

• Larger time-step sizes save computing time.

• Parachute canopy in Case 1 is positioned lower than it was in Case 0.

• Parachute diameter in Case 1 is smaller than it was in Case 0.

Case 1 Case 2

Case 3 Case 4

Case 0 results look reasonable. We test

• different pressures

• different time-step sizes (Dt)• different structural damping coefficients (η)

to see how the settled parachute shape changes.

• Obtain deformed parachute shape for fluid computations of the

Orion drogue parachute [1] in compressible-flow regime [2]

• Study the pressure dependence and effect of time-step size, and

damping coefficient

• Mesh resolution effect

• Fluid computations with the deformed shape

Pressure (Pa) Dt (s) η (s-1)

1,000 0.001 0

Pressure (Pa) Dt (s) η (s-1)

1,500 0.002 0

Pressure (Pa) Dt (s) η (s-1)

1,500 0.003 0

• Parachute canopy in Case 2 is positioned higher than it was in Case 0.

• Parachute diameter in Case 2 is larger than it was in Case 0.

Pressure (Pa) Dt (s) η (s-1)

1,500 0.001 0

Pressure (Pa) Dt (s) η (s-1)

3,000 0.001 0

Case 0 (76.0% D0) Case 4 (76.8% D0)Case 3 (76.4% D0)

Initial shape (D0 = 23 ft)

Settled shape (76.0% D0)

Objective

Case 0 (76.0% D0) Case 1 (75.6% D0) Case 2 (76.8% D0)

Acknowledgement

Conclusions

Damping Effect

Case 5 Case 6

• Parachute movement in Case 5 is close to what it was in Case 0.

• Movement details in Case 6 are not captured, but not needed.

• Settled parachute diameter in both cases is close to what it was in Case 0.

• Initial movement in both cases is different from what it was in Case 0.

• The settled shape is almost the same.

Pressure (Pa) Dt (s) η (s-1)

1,500 0.001 14

Pressure (Pa) Dt (s) η (s-1)

1,500 0.001 140

Future Directions

Case 5 (76.2% D0) Case 6 (76.3% D0)Case 0 (76.0% D0)