Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-17T22:41:24.762Z Has data issue: false hasContentIssue false

On the flow field of a rapidly oscillating airfoil in a supersonic flow

Published online by Cambridge University Press:  29 March 2006

M. Kurosaka
Affiliation:
Research and Development Center, General Electric Company, Schenectady, New York

Abstract

This paper examines the features of the flow field off the surface of an oscillating flat-plate airfoil immersed in a two-dimensional supersonic flow Although the exact linearized solution for a supersonic unsteady airfoil has been known for a long time, its expression in the form of an integral is not convenient for a physical interpretation. In the present paper, the quintessential features of the flow field are extracted from the exact solution by obtaining an asymptotic expansion in descending powers of a frequency parameter through the repeated use of the stationary-phase and steepest descent methods. It is found that the flow field consists of two dominant and competing signals: one is the acoustic ray or that component arising from Lighthill's ‘convecting slab’ and the other is the leading-edge disturbance propagating as a convecting wavelet. The flow field is found to be divided into several identifiable regions defined by the relative magnitude of the signals, and the asymptotic expansions appropriate for each flow region are derived along with their parametric restrictions. Such intimate knowledge of the flow field in unsteady, supersonic flow is of interest for interference aerodynamics and related acoustic problems.

Type
Research Article
Copyright
© 1974 Cambridge University Press

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ashley, H. & Zartarian, G. 1956 J. Aero. Sci. 23, 1109.
Candel, S. M. 1972 Ph.D. thesis, California Institute of Technology.
Garrick, I. E. & Rubinow, S. I. 1946 N.A.C.A. Rep. no. 846.
Hanin, M. 1960 Bull. Res. Counc. Israel, no. 8C, p. 25.
Hayes, W. D. 1947 Quart. Appl. Math. 5, 105.
Landahl, M., Ashley, H. & Mollo-Christensen, E. L. 1955 J. Aero. Sci. 22, 581.
Lighthill, M. J. 1953 J. Aero. Sci. 20, 402.
Miles, J. W. 1959 The Potential Theory of Unsteady Supersonic Flow. Cambridge University Press.
Morgan, H. G., Huckel, V. & Runyan, H. L. 1958 N.A.C.A. Tech. Note, no. 4335.
Morse, P. M. & Ingard, K. U. 1968 Theoretical Acoustics. McGraw-Hill.
Sommerfeld, A. 1954 Optics. Academic.