Study of hypersonic aerodynamics using free flight experiments

An aerodynamic database (AEDB) documents the forces acting on a flight vehicle over its design range of attitudes and flight conditions. It is critical for calculating stability and designing control algorithms. Today, most hypersonic vehicle AEDBs are created numerically and validated with force balance measurements on fixed, sting-mounted models in wind tunnels. However, the results can be challenging to resolve and are unavoidably compromised by sting interference. This thesis describes experimental studies conducted using the University of Southern Queensland’s hypersonic wind tunnel (TUSQ) to enhance the capabilities of the free flight ground testing (FFGT) technique. In FFGT, models are released into the test flow core and fly freely in it. The length of the steady test flow permits significant motion of the model, allowing significant regions of the vehicle’s flight envelope to be examined in a single experiment. The model’s accelerations and rates of turn are measured and recorded in flight using miniaturised onboard instrumentation. The AEDB is built from the aerodynamic forces deduced directly from this data. Direct acceleration measurement is inherently superior in determining aerodynamic force when compared to image analysis, where displacements are measured, and forces are inferred from the differentiated result. The differentiation process is very sensitive to noise, hence will introduce uncertainty. The technique was applied to sub-scale models of ESA’s HEXAFLY-INT flight test vehicle. The significant regions of an AEDB constructed in this way compared well with numerical predictions and other experimental studies existing in the literature. The technique was then extended to the case of multiple instrumented bodies interacting within a flow field simulating the stage separation dynamics between a generic payload and a scaled second stage booster. Measured results served as validation for inviscid numerical simulations conducted by a third party. Temporally resolved surface pressure maps were successfully acquired for the first time on a generic free flying model coated with pressure sensitive paint moving significantly relative to its size. Experimental results compared well with analytical and numerical predictions.

Grantor dc:publisher

UNSW, Sydney

Year dc:date

2018

Author dc:creator

• Kennell, Christopher

• Experimental
• Aerospace
• Hypersonic
• Free flight
• Scaling
• Pressure Sensitive Paint
• IMU
• 3D printing

Statement dc:rights

• open access
• CC BY-NC-ND 3.0
• free_to_read

Licence

• https://purl.org/coar/access_right/c_abf2
• https://creativecommons.org/licenses/by-nc-nd/3.0/au/

Language dc:language

EN

Identifier

https://doi.org/10.26190/unsworks/20905

OAI identifier oai:identifier

oai:unsworks.library.unsw.edu.au:1959.4/61194