Accession Number:

ADA191336

Title:

Tip Vortices of Isolated Wings and Helicopter Rotor Blades.

Descriptive Note:

Final rept. Nov 84-Nov 87,

Corporate Author:

JAI ASSOCIATES INC MOUNTAIN VIEW CA

Personal Author(s):

• Srinivasan, Ganapathi R.

Report Date:

1987-12-01

Pagination or Media Count:

86.0

Abstract:

Thin layer Navier-Stokes equations are solved numerically for simulating the flowfields of isolated wings and helicopter rotor blades with a particular emphasis on understanding the formation and roll-up of tip vortices in subsonic and transonic flows. Several test cases consisting of wings and rotor blades of different planforms have been considered to examine the influence of the tip-cap shape, the tip-planform, the freestream Mach number, and the effect of centrifugal forces of rotation. A fairly good definition of the formation and roll-up of the tip vortex is demonstrated for all the cases considered here. Finally, the calculated lift, drag and pitching-moment coefficients agree well with the experimentally determined values, where available. Alternate methods of simulating the hovering rotor flowfields in blade-fixed mode that have the circulation distribution as hovering blade are explored. The results and discussion are presented. Keywords Viscous, Unsteady flows Zonal grid topology Thin layer Navier-Stokes Tip vortices Inertial reference frame Three-dimensional flow separation Steady flows, Fluid dynamics.

Descriptors:

• *ROTOR BLADES(ROTARY WINGS)
• *VORTICES
• *WING TIPS
• BLADES
• CENTRIFUGAL FORCE
• CIRCULATION
• DISTRIBUTION
• DRAG
• FLOW FIELDS
• FLOW SEPARATION
• FLUID DYNAMICS
• FREE STREAM
• GRIDS
• HELICOPTER ROTORS
• HOVERING
• ISOLATION
• LAYERS
• MACH NUMBER
• NAVIER STOKES EQUATIONS
• ROTATION
• ROTOR BLADES
• ROTORS
• STEADY FLOW
• SUBSONIC FLOW
• THINNESS
• THREE DIMENSIONAL FLOW
• TOPOLOGY
• TRANSONIC FLOW
• UNSTEADY FLOW
• VISCOUS FLOW
• WINGS
• FRONT ENDS AND SURFACES

Subject Categories:

• Aerodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE