CFD based methods for the computation of generalized aerodynamic forces

In the present work time and frequency domain generalized aerodynamic forces (GAFs) are presented. For this purpose the first four structural modes of the AGARD 445.6 configuration are used to compute the corresponding generalized aerodynamic forces with the Euler methods AER-Eu (time domain) and AER-SDEu (frequency domain). Furthermore a reduced order model (ROM) of the aerodynamic system is generated as a linear state space model for fast computations of GAFs in the time domain. In order to generate the ROM the impulse response in the form of GAFs are computed with AER-Eu and further processed for the system identification of the CFD-System. The transfer from time domain into frequency domain is achieved via the Fourier analysis of the time series of the harmonic responses as well as the discrete Fourier transformation of the impulse responses for modal movement of the body. The results correlate well between the full CFD solution and the solution of the ROM.