A new method for predicting rotor wake geometries and downwash veloicty field

摘要

A new method for predicting rotor wake in low speed and hovering flight is descibed to investigate the motion of the helical tip vortex. Beginning with the generalized wake model, a semi-empirical correction for the vortex core effect on rotor wake is made and free wake calculation is carried out. As an example of its engineering application, the calcualted downwash velocity field along the rocket laucnch line is presented and simply analysed. In terms of theory, the method developed here may provide a referable basis for futher study of the formation mode of the tip vortex core interior structure.