A Computational and Experimental Study of High-Speed Impulsive Noise from a Rotating Cylinder,
Abstract
This work presents an alternative to current integral approaches that do not accurately predict noise from a delocalized rotor. The two-dimensional model of this study is essentially an airfoil shape mounted on the side of cylinder which spins at transonic speeds between two end-walls. A finite-difference conservative formulation of the two-dimensional, transonic full-potential equations solves the flow field away from the body directly and hence predicts the beginning of delocalization and the associated wave propagation. The potential method has an inherent stability limit a free-stream velocity of Mach 1.4 and shows a troubling sensitivity to the choice of outer boundary conditions. Methods for correctly handling these two problems are shown. A two-dimensional experiment that described. The computer prediction of the flow expected in the experiment is presented as are some limited experimental results. Results taken from a three-dimensional results correlate to those from an actual rotor. Results for low-aspect-ratio rotors show a higher delocalization Mach number for decreasing aspect ratio and a greater dependence on thickness. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1987
- Accession Number
- ADA178986
Entities
People
- T. W. Purcell