Using automatic differentiation to create a nonlinear reduced-order-model aerodynamic solver

A novel nonlinear reduced-order-modeling technique for computational aerodynamics and aeroelasticity is presented. The method is based on a Taylor series expansion of a frequency-domain harmonic balance computational fluid dynamic solver residual. The first- and second-order gradient matrices and tensors of the Taylor series expansion are computed using automatic differentiation via FORTRAN 90=95 operator overloading. A Ritz-type expansion using proper orthogonal decomposition shapes is then used in the Taylor series expansion to create the nonlinear reduced-order model. The nonlinear reduced-order-modeling technique is applied to a viscous flow about an aeroelastic NLR 7301 airfoil model to determine limit cycle oscillations. Computational times are decreased from hours to seconds using the nonlinear reduced-order model. Copyright © 2009 by Jeffrey P. Thomas, Earl H. Dowell, and Kenneth C. Hall.

Duke Scholars

Author Jeffrey P. Thomas Thomas Lord Department of Mechanical Engineering and Materia ...

Author Earl H. Dowell Thomas Lord Department of Mechanical Engineering and Materia ...

Author Kenneth C. Hall Thomas Lord Department of Mechanical Engineering and Materia ...