ACTA AERONAUTICAET ASTRONAUTICA SINICA >
Time Spectral Method for Numerical Simulation of Unsteady Viscous Flow over Oscillating Airfoil and Wing
Received date: 2012-04-06
Revised date: 2012-05-27
Online published: 2013-04-23
Supported by
National Natural Science Foundation of China (11172070); Shanghai Municipal Natural Science Foundation (09ZR1411400); Graduates' Innovation Foundation (EYH2126022) *Corresponding author. Tel.: 021-55665534 E-mail: amyang@fudan.edu.cn
The traditional dual time stepping formula is comparatively inefficient in solving unsteady problems due to its repeated transitional iteration stepping. In view of the characteristics of periodical unsteady flow, a high efficiency time spectral method based on discrete fourier transformation is hereby developed for such type of flow over an oscillating airfoil and wing. Roe's flux difference splitter scheme is utilized to discretize the convective terms of the time-space coupled Reynolds-averaged Navier-Stokes (RANS) equations. Time spectral method is used to treat the physical time derivative terms while the implicit LU-SGS (Lower-Upper Symmetric Gauss-Seidel) scheme deals with pseudo time stepping. Meanwhile, the physi-cal time terms of Spalart-Allmaras's one equation turbulence model, which acts as our turbulence model, is also discretized by the time spectral method in consideration of the turbulence's time-space coupling effect. In order to further improve efficiency, methods like local time step and multigrid algorithm are used to accelerate the convergence of RANS equation's solution. In the numerical examples section, the periodical unsteady flow field over an oscillating NACA0012 airfoil and Lann wing is simulated numerically. Results show that the time spectral method possesses obvious advantages in reducing computational cost and improving calculation accuracy as compared with the conventional dual time stepping formula.
YANG Xiaoquan , CHENG Sukun , YANG Aiming , SUN Gang . Time Spectral Method for Numerical Simulation of Unsteady Viscous Flow over Oscillating Airfoil and Wing[J]. ACTA AERONAUTICAET ASTRONAUTICA SINICA, 2013 , 34(4) : 787 -797 . DOI: 10.7527/S1000-6893.2013.0138
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