Dynamic stall of a constant-rate pitching airfoil

A computational study is presented for the dynamic stall of an airfoil that is pitched at a constant rate from zero incidence to a high angle of attack. The unsteady flow is simulated employing the mass-averaged NavierStokes equations and an algebraic turbulent eddy viscosity model. The approach is first validated by comparison of computed and experimental results for a pitching airfoil at low freestream Mach numbers. The computed dynamic stall events, as well as the computed effects of pitch rate and axis location, are found in qualitative agreement with experimental observations. The effect of compressibility on dynamic stall is investigated. As the freestream Mach number increases, the appearance of a supersonic region provides—through the shock/boundarylayer interaction—an additional mechanism in the dynamic stall process. The main effects of compressibility are found to be 1) a change from trailing-edge stall to leading-edge stall and 2) a reduction in the stall delay and in the attained maximum lift.

[1]  C. D. Harris.  Two-dimensional aerodynamic characteristics of the NACA 0012 airfoil in the Langley 8 foot transonic pressure tunnel , 1981 .

[2]  L. Ericsson.  Review of transition effects on the problem of dynamic simulation , 1988 .

[3]  L. Ericsson,et al.  Dynamic Effects of Shock-Induced Flow Separation , 1975 .

[4]  M. Visbal,et al.  Evaluation of an implicit Navier-Stokes solver for some unsteady separated flows , 1986 .

[5]  M. Francis,et al.  Airfoil dynamic stall performance with large-amplitude motions , 1985 .

[6]  O. Lambert,et al.  Dynamic Stall on Advanced Airfoil Sections , 1981 .

[7]  M. Visbal,et al.  Generation of orthogonal and nearly orthogonal coordinates with gridcontrol near boundaries , 1982 .

[8]  James D. Lang,et al.  Unsteady Aerodynamics and Dynamic Aircraft Maneuverability , 1985 .

[9]  D. Chou,et al.  Forced Unsteady Vortex Flows Driven by Pitching Airfoils , 1987 .

[10]  M. Visbal,et al.  Comparative Study Between Two Navier-Stokes Algorithms for Transonic Airfoils , 1986 .

[11]  F. Carta,et al.  Airfoil dynamic stall at constant pitch rate and high Reynolds number , 1987 .

[12]  M. Robinson,et al.  Visualization of three-dimensional forced unsteady separated flow , 1986 .

[13]  Terry L. Holst,et al.  Viscous transonic airfoil workshop compendium of results , 1988 .

[14]  Hank E. Helin,et al.  Interrelated Effects of Pitch Rate and Pivot Point on Airfoil Dynamic Stall , 1985 .

[15]  W. Mccroskey,et al.  Dynamic Stall Experiments on Oscillating Airfoils , 1975 .

[16]  H. Lomax,et al.  Thin-layer approximation and algebraic model for separated turbulent flows , 1978 .

[17]  L. Carr.  Progress in analysis and prediction of dynamic stall , 1988 .

[18]  J. P. Reding,et al.  Unsteady airfoil stall , 1969 .

[19]  E. Jumper,et al.  The Effect of Pitch Location on Dynamic Stall , 1989 .

[20]  R. F. Warming,et al.  An Implicit Factored Scheme for the Compressible Navier-Stokes Equations , 1977 .

[21]  Lars E. Ericsson,et al.  Unsteady airfoil stall review and extension , 1971 .

[22]  J. H. Strickland,et al.  Force coefficients for a NACA-0015 airfoil undergoing constant pitchrate motions , 1987 .

[23]  W. C. Rose,et al.  The turbulent mean-flow, Reynolds-stress, and heat flux equations in mass-averaged dependent variables , 1973 .

[24]  J. Steger.  Implicit Finite-Difference Simulation of Flow about Arbitrary Two-Dimensional Geometries , 1978 .

[25]  I. Tuncer,et al.  Unsteady aerodynamics of rapidly pitched airfoils , 1986 .

[26]  M. Visbal,et al.  Investigation of the flow structure around a rapidly pitching airfoil , 1989 .

[27]  Eric J. Jumper,et al.  Lift-curve characteristics for an airfoil pitching at constant rate , 1986 .

[28]  M. J. Stanek,et al.  Investigation of vortex development on a pitching slender body of revolution , 1991 .