Accession Number : ADA182389

Title :   Free-Wake Analysis of a Rotor in Hover,

Corporate Author : OHIO STATE UNIV COLUMBUS

Personal Author(s) : Chen,C S ; Velkoff,H R ; Tung,C

PDF Url : ADA182389

Report Date : Jan 1987

Pagination or Media Count : 9

Abstract : A numerical method based on the axisymmetric, incompressible Navier-Stokes equations is combined with a lifting surface code to predict the vortex wake of hovering rotors. The lifting surface code, AMI Hover, is used to obtain the circulation distribution on the blade. This circulation distribution is fed into the Navier-Stokes code to compute the vortex wake under this specified circulation distribution. An iteration approach is used between these two codes to converge the circulation distribution and the shape of the vortex wake. A relaxation scheme is developed to resolve the instability encountered among the tip vortices. A reconcentration scheme is used to solve the diffusion problem due to the strong artificial viscosity. The results from the present method are compared with experimental data obtained by smoke-flow visualization and hot-wire measurements for several rotor blade configurations. The comparisons show that the present method is able to predict the complex wake system shed by a hovering rotor.

Descriptors :   **HOVERING, *HELICOPTER ROTORS, *VORTEX SHEDDING, VISCOSITY, CIRCULATION, DISTRIBUTION, DIFFUSION, ROTORS, CODING, LIFTING SURFACES, NUMERICAL METHODS AND PROCEDURES, AXISYMMETRIC, INCOMPRESSIBILITY, NAVIER STOKES EQUATIONS, HOT WIRE, MEASUREMENT, ITERATIONS, RELAXATION, ROTOR BLADES(ROTARY WINGS), SMOKE, FLOW VISUALIZATION, HOT WIRE ANEMOMETERS, VORTICES, WAKE

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE