The effects of rotational flow, viscosity, thickness, and shape on transonic flutter dip phenomena

The transonic flutter dip phenomena on thin airfoils, which are employed for propfan blades, is investigated using an integrated Euler/Navier-Stokes code and a two degrees of freedom typical section structural model. As a part of the code validation, the flutter characteristics of the NACA 64A010 airfoil are also investigated. In addition, the effects of artificial dissipation models, rotational flow, initial conditions, mean angle of attack, viscosity, airfoil thickness and shape on flutter are investigated. The results obtained with a Euler code for the NACA 64A010 airfoil are in reasonable agreement with published results obtained by using transonic small disturbance and Euler codes. The two artificial dissipation models, one based on the local pressure gradient scaled by a common factor and the other based on the local pressure gradient scaled by a spectral radius, predicted the same flutter speeds except in the recovery region for the case studied. The effects of rotational flow, initial conditions, mean angle of attack, and viscosity for the Reynold's number studied seem to be negligible or small on the minima of the flutter dip.

[1]  John W. Edwards,et al.  Airfoil shape and thickness effects on transonic airloads and flutter , 1983 .

[2]  John W. Edwards,et al.  Computational methods for unsteady transonic flows , 1987 .

[3]  P. Goorjian,et al.  Computation of Unsteady Transonic Flows by the Indicial Method , 1977 .

[4]  Koji Isogai,et al.  Numerical Study of Transonic Flutter of A Two-dimensional Airfoil , 1980 .

[5]  G. V. Narayanan,et al.  Analytical flutter investigation of a composite propfan model , 1989 .

[6]  N. Sankar,et al.  Numerical solution of unsteady viscous flow past rotor sections , 1985 .

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

[8]  Thomas H. Pulliam,et al.  Artificial Dissipation Models for the Euler Equations , 1985 .

[9]  R. Sorenson,et al.  Two-Dimensional Grids About Airfoils and Other Shapes , 1982 .

[10]  Eli Turkel,et al.  Artificial dissipation and central difference schemes for the Euler and Navier-Stokes equations , 1987 .

[11]  Holt Ashley,et al.  Role of Shocks in the "Sub-Transonic" Flutter Phenomenon , 1980 .

[12]  F. E. Eastep,et al.  Transonic Flutter Analysis of a Rectangular Wing with Conventional Airfoil Sections , 1979 .

[13]  L. Sankar,et al.  Analysis of Viscous Transonic Flow Over Airfoil Sections , 1987 .

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

[15]  K. Isogai,et al.  Transonic dip mechanism of flutter of a sweptback wing. II , 1981 .

[16]  C. J. Borland,et al.  Nonlinear transonic flutter analysis , 1982 .

[17]  Rodrick V. Chima,et al.  Explicit multigrid algorithm for quasi-three-dimensional viscous flows in turbomachinery , 1987 .

[18]  W. Mccroskey,et al.  Numerical simulations of unsteady airfoil-vortex interactions , 1987 .

[19]  D. Rizzetta,et al.  Numerical Solution of Three-Dimensional Unsteady Transonic Flow over Swept Wings , 1982 .

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

[21]  Earl H. Dowell,et al.  Flutter Analysis Using Nonlinear Aerodynamic Forces , 1984 .

[22]  Alfred G. Striz,et al.  Application of Transonic Codes to Flutter Analysis of Conventional and Supercritical Airfoils , 1981 .

[23]  R. Sorenson.  A computer program to generate two-dimensional grids about airfoils and other shapes by the use of Poisson's equation , 1980 .

[24]  Robert E. Kielb,et al.  Bending-torsion flutter of a highly swept advanced turboprop , 1981 .

[25]  V. Elchuri,et al.  Flutter analysis of advanced turbopropellers , 1984 .