A mapped Chebyshev pseudospectral method is developed as an accurate and yet efficient approach to solve unsteady flows. Preserving the conservation laws, the method discretizes a spatial-derivative term implicitly, whereas a time-derivative term is treated explicitly using the mapped Chebyshev collocation operator. Because standard Chebyshev points make the corresponding spectral derivative matrix ill-conditioned due to uneven distribution of the Chebyshev points clustered heavily toward the ends of the interval, an inverse sine mapping function is applied to the Chebyshev collocation operator so that the point distribution becomes more uniform in a time domain and mitigates numerical instabilities correspondingly. Computations of unsteady flows, including the one-dimensional Burgers’ equation and two-dimensional airfoil flows under oscillation and plunging motions, are carried out. Numerical results of the present study are compared with those of the conventional time-marching solution method and the harmonic balance method for each application and demonstrate high accuracy at much reduced computational cost. The method shows great potential to solve general unsteady flows involving both periodic and nonperiodic motions.
Mapped Chebyshev Pseudospectral Method for Unsteady Flow Analysis
AIAA Journal ; 53 , 12 ; 3805-3820
2015-12-01
Conference paper , Article (Journal)
Electronic Resource
English
Mapped Chebyshev Pseudospectral Method for Unsteady Flow Analysis
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