Photogrammetry measurements of blunt body dynamics in a supersonic wind tunnel
File(s)
Published version
Author(s)
Innocenzi, Pietro
Bruce, Paul
Navarro-Martinez, Salvador
Type
Journal Article
Abstract
Abstract
This paper presents free-oscillation experiments of a blunt body conducted in a high-speed wind tunnel, with the model motion measured using photogrammetry. A faceted blunt model, mounted on a spherical air bearing, is free to rotate in
roll, pitch, and yaw in response to the freestream flow (M= 2). Four synchronised high-speed cameras capture the model from multiple angles, and the unique coded targets printed on the model’s surface are reconstructed as points in 3D space, achieving accuracy within 1◦
for both static and dynamic measurements. The Kabsch algorithm is used to find the optimal rotation between two point clouds, hence allowing reconstruction of the angular motion over the entire run. The method
shows promise for free-oscillation tests in high-speed ground facilities, offering advantages over ballistic range and free flight tests such as a constant freestream velocity and hundreds of oscillation cycles. This capability enables the observation of dynamic instabilities that develop over extended timescales, thus revealing a precessional instability previously reported
only for slender bodies at hypersonic Mach numbers.
This paper presents free-oscillation experiments of a blunt body conducted in a high-speed wind tunnel, with the model motion measured using photogrammetry. A faceted blunt model, mounted on a spherical air bearing, is free to rotate in
roll, pitch, and yaw in response to the freestream flow (M= 2). Four synchronised high-speed cameras capture the model from multiple angles, and the unique coded targets printed on the model’s surface are reconstructed as points in 3D space, achieving accuracy within 1◦
for both static and dynamic measurements. The Kabsch algorithm is used to find the optimal rotation between two point clouds, hence allowing reconstruction of the angular motion over the entire run. The method
shows promise for free-oscillation tests in high-speed ground facilities, offering advantages over ballistic range and free flight tests such as a constant freestream velocity and hundreds of oscillation cycles. This capability enables the observation of dynamic instabilities that develop over extended timescales, thus revealing a precessional instability previously reported
only for slender bodies at hypersonic Mach numbers.
Date Issued
2026-02-01
Date Acceptance
2026-01-12
Citation
Experiments in Fluids, 2026, 67 (2)
ISSN
0723-4864
Publisher
Springer
Journal / Book Title
Experiments in Fluids
Volume
67
Issue
2
Copyright Statement
© The Author(s) 2026 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
License URL
Publication Status
Published
Article Number
23
Date Publish Online
2026-01-28