Aerodynamics of inclined cylindrical bodies free-flying in a hypersonic flowfield

Patrick M. Seltner, Sebastian Willems, Ali Gülhan, Eric C. Stern, Joseph M. Brock, Michael J. Aftosmis

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Abstract: The influence of the flight attitude on aerodynamic coefficients and static stability of cylindrical bodies in hypersonic flows is of interest in understanding the re/entry of space debris, meteoroid fragments, launch-vehicle stages and other rotating objects. Experiments were therefore carried out in the hypersonic wind tunnel H2K at the German Aerospace Center (DLR) in Cologne. A free-flight technique was employed in H2K, which enables a continuous rotation of the cylinder without any sting interferences in a broad angular range from 0 to 90. A high-speed stereo-tracking technique measured the model motion during free-flight and high-speed schlieren provided documentation of the flow topology. Aerodynamic coefficients were determined in careful post-processing, based on the measured 6-degrees-of-freedom (6DoF) motion data. Numerical simulations by NASA’s flow solvers Cart3D and US3D were performed for comparison purposes. As a result, the experimental and numerical data show a good agreement. The inclination of the cylinder strongly effects both the flowfield and aerodynamic loads. Experiments and simulations with concave cylinders showed marked difference in aerodynamic behavior due to the presence of a shock–shock interaction (SSI) near the middle of the model. Graphic abstract: [Figure not available: see fulltext.]

Original languageEnglish (US)
Article number182
JournalExperiments in Fluids
Issue number9
StatePublished - Aug 13 2021
Externally publishedYes

Bibliographical note

Funding Information:
The present work has been performed within the framework of the Program Helmholtz Research School on Security Technologies (HRSST) and benefited from a funding by the DLR program directorate Defence & Security. Support was also given by NASA?s Planetary Defense Coordination Office (PDCO) managed by Mr. Lindley Johnson, who has funded the work of the Asteroid Threat Assessment Project (ATAP). Special thanks also go to Mr. Michael Kosbow and Mr. Marco Schmors for the operation of the H2K facility.

Publisher Copyright:
© 2021, The Author(s).


  • Atmospheric entry
  • CFD simulation
  • Free-flight technique
  • High-speed aerodynamics
  • Hypersonic wind tunnel
  • Shock–shock interaction


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