Recently, we published a manuscript for our research on the fluid-structure interaction of inflatable membrane aeroshell in the renowned journal: Aerospace Science and Technology. This work developed a numerical framework for the fluid-structure interaction of flexible reentry vehicles validated by the transonic wind tunnel experiment focusing on the structural deformation and oscillatory behavior in the subsonic flow regime.
Research Summary
Inflatable aeroshells experience significant aerodynamic loads during atmospheric entry. The flexible membrane deforms by the aerodynamic forces, and such deformation changes the flow field, which can change the aerodynamic characteristics and increase the deformation even further. So, complex fluid-structure interaction problems appear during atmospheric entry. Thus, the aerodynamic characteristics during atmospheric entry must be adequately evaluated through fluid-structure coupled modelling for the reliable performance prediction of such vehicles. Based on this newly established model, aerodynamic behavior and coupled fluid-structural characteristics are systematically examined under subsonic conditions and verified by experimental wind tunnel investigation, with particular attention given to the transient oscillatory behavior of the membrane aeroshell that was found in the free flight test.
Fig. 1: Experimental model
Fig.2: Instantaneous velocity distribution
The results revealed that the decelerated flow generated a high-pressure region in the front and a low-pressure region in the rear of the aeroshell. The separated flow produced a vortex ring behind the aeroshell, creating a shear layer in the wake region. Oscillatory swing motion, caused by force from the fluid, was reproduced by effectively setting Young’s modulus of the membrane material. The oscillation frequency of the swing motion was the same as the lift and pitching moment oscillation frequency. This indicated that the swing motion also affected the aerodynamics of the vehicle.
Thoughts
Aerospace Science and Technology is one of the most prestigious journals in aerospace engineering. The hardest part of publishing in this journal was preparing the response of the reviewers. In this case, the experts provided critical questions we had to respond to. There were several sources of error in the wind tunnel experiment, and it took an effort to find out and sensibly portray the limitations. Without the help of the co-authors, it would not be possible. Writing and publishing a manuscript is challenging; however, I enjoyed the whole process. It made me feel worthy and satisfied and enhanced my writing skills.
Manuscript
The published manuscript can be accessed at the following URL:
Saha, SK, Tobari, J., Takahashi, Y., Oshima, N., Moriyoshi, T., Yamada, K., & Shibata, R. (2023). Fluid-Structure Interaction Characteristics of Inflatable Reentry Aeroshell at Subsonic Speed. Aerospace Science and Technology, 108112.
Sanjoy Kumar Saha
March 10, 2023
