Accession Number : ADA183092

Title :   Unsteady Separation Characteristics of Airfoils Operating Under Dynamic Stall Conditions,

Corporate Author : DEUTSCHE GESELLSCHAFT FUER LUFT- UND RAUMFAHRT E V GOETTINGEN (GERMANY F R)

Personal Author(s) : Geissler,Wolfgang ; Carr,Lawrence W ; Cebeci,Tuncer

PDF Url : ADA183092

Report Date : 25 Sep 1986

Pagination or Media Count : 15

Abstract : Unsteady viscous/inviscid interaction phenomena were investigated on airfoils operating under dynamic stall conditions. It is well known from experiments that, in the upstroke region of a sinusoidally oscillating airfoil, the flow remains attached up to incidences considerably larger than the static stall angle. Reversed flow areas develop close to the airfoil surface without boundary layer separation. These complicated flow phenomena are investigated in the present study on the basis of coupling procedures between a time-dependent inviscid panel method and 2-d unsteady boundary layer codes. Two strategies are pursued: 1. Coupling of inviscid panel method with boundary layer code-direct mode; and 2. Strong coupling of inviscid panel method with boundary layer code-inverse mode. The main features of the unsteady time-marching panel method and boundary layer codes are discussed. Emphasis is placed on the investigation of numerical stability and the phenomenon of unsteady separation.

Descriptors :   *FLOW SEPARATION, *STALLING, *UNSTEADY FLOW, AIRFOILS, SURFACES, BOUNDARY LAYER, CODING, COUPLING(INTERACTION), FLOW, NUMERICAL ANALYSIS, STABILITY, MATHEMATICAL MODELS, PANELS, DYNAMICS, INVISCID FLOW, OSCILLATION, REVERSIBLE, TWO DIMENSIONAL, VISCOUS FLOW, ROTOR BLADES(ROTARY WINGS), HELICOPTERS, BOUNDARY LAYER FLOW, ANGLES, STALLING, STATICS, STRATEGY, TIME DEPENDENCE, WEST GERMANY

Subject Categories : Aerodynamics
      Numerical Mathematics

Distribution Statement : APPROVED FOR PUBLIC RELEASE