Summary of MIT Research on Dynamic Stall and Blade-Vortex Interaction, 1971-1974.
Abstract
A previous MIT investigation indicated that during the close interaction of a vortex with a rotating blade, the measured vortex-induced unsteady loading on the blade differed greatly from that predicted by lifting-surface theory, both in peak magnitude and in chordwise distribution. The experimental results suggested the occurrence of local separation in the region of most intense vortex-induced loading. During the past year, blade-vortex interaction was studied by subjecting the midsection of a pressure-instrumented airfoil, mounted horizontally and perpendicular to the wind-tunnel airstream, to the impingement of a vortex moving periodically in the vertical plane from a point below the airfoil to a point above the airfoil and back again. The results of this investigation have shown that the maximum vortex-induced lift coefficients are of the order of 0.2 to 0.3. The vortex-induced peak loadings were found to be independent of the frequency of vortex impingement (i.e., vortex approach velocity), proportional to vortex strength, and only weakly dependent upon airfoil angle of attack and angle of yaw.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1974
- Accession Number
- ADA008091
Entities
People
- Norman D. Ham
Organizations
- Massachusetts Institute of Technology