Analysis of Similitude Requirements and Scaling Laws for Transonic Buffeting
Report Number: RTD-TDR 63-4197 Part I, p. 49
Author(s): Peterson, H. C., Ezra, A. A.
Corporate Author(s): The Martin Company
Laboratory: Air Force Flight Dynamics Laboratory
Date of Publication: 1964-03
Pages: 32
DoD Task:
Abstract:
When a launch vehicle accelerates through Mach 1, a shock wave forms, remains attached to the nose for a brief time and then separates as the Mach number increases. During the period of shock wave attachment, intense local unsteady aerodynamic pressures of an oscillatory nature are generated. These unsteady pressures which give rise to the violent shaking referred to as transonic buffeting forces must be specified, for analytical purposes, as a non-dimensional plot of power spectral density versus frequency. Due to the limitations of the present theoretical knowledge, these power spectral density curves must be derived from wind-tunnel tests. In order to conduct valid scale model tests, to determine the transonic buffeting excitation, a careful analysis of similitude requirements is necessary; and it is mandatory to determine the importance of those similitude requirements that cannot be provided due to the limitations of existing wind tunnels. This paper derives the similitude requirements and the corresponding scaling laws for small scale experimental work and describes the different experimental approaches that can be used to circumvent the practical difficulties of fulfilling all the similitude requirements.
Provenance: Bombardier/Aero
Author(s): Peterson, H. C., Ezra, A. A.
Corporate Author(s): The Martin Company
Laboratory: Air Force Flight Dynamics Laboratory
Date of Publication: 1964-03
Pages: 32
DoD Task:
Abstract:
When a launch vehicle accelerates through Mach 1, a shock wave forms, remains attached to the nose for a brief time and then separates as the Mach number increases. During the period of shock wave attachment, intense local unsteady aerodynamic pressures of an oscillatory nature are generated. These unsteady pressures which give rise to the violent shaking referred to as transonic buffeting forces must be specified, for analytical purposes, as a non-dimensional plot of power spectral density versus frequency. Due to the limitations of the present theoretical knowledge, these power spectral density curves must be derived from wind-tunnel tests. In order to conduct valid scale model tests, to determine the transonic buffeting excitation, a careful analysis of similitude requirements is necessary; and it is mandatory to determine the importance of those similitude requirements that cannot be provided due to the limitations of existing wind tunnels. This paper derives the similitude requirements and the corresponding scaling laws for small scale experimental work and describes the different experimental approaches that can be used to circumvent the practical difficulties of fulfilling all the similitude requirements.
Provenance: Bombardier/Aero
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This report is part of the following conference:
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Proceedings of Symposium on Aeroelastic & Dynamic Modeling Technology
RTD TDR 63-4197 Part I