AN EXTENDED LIFTING LINE THEORY FOR THE LOADS ON A ROTOR BLADE IN THE VICINITY OF A VORTEX
MASSACHUSETTS INST OF TECH CAMBRIDGE AEROELASTIC AND STRUCTURES RESEARCH LAB
Pagination or Media Count:
An extension of the lifting line theory is described which is based upon the argument that in the vicinity of the vortex the flow pattern will be more like that on a low aspect ratio wing, while still retaining the characteristics of high aspect ratio well away from the vortex. Spanwise circulation distributions are given for a blade of aspect ratio 20 for vortex distances from the blade varying between chord and one-tenth chord. The results of lifting line and modified lifting theory are compared and it is found that, except when the vortex is very close to the blade, there is little to choose between the results. When the vortex is very close to the blade, the modified theory predicts appreciably smaller circulation and a less peaky spanwise distribution near to the vortex, but no fundamental changes are found and it is thought unlikely that a more sophisticated lifting surface theory will lead to any significant changes in the results. Some suggestions are made as to the proper procedure for developing a lifting surface theory.
- Fluid Mechanics