An Implicit Adaptive Non-Linear Frequency Domain Method (pNLFD) for Viscous Periodic Steady State Flows on Deformable Grids

2011 ◽  
Author(s):  
Ali Mosahebi Mohamadi ◽  
Siva Nadarajah
Keyword(s):  
Steady State ◽  
Frequency Domain ◽  
Frequency Domain Method ◽  
Linear Frequency ◽  
Domain Method ◽  
Non Linear ◽  
Periodic Steady State

scholarly journals A Fast Frequency Domain Method for Steady-State Solution of Forced Vibration of System with Complex Damping

2020 ◽  
Vol 10 (10) ◽  
pp. 3442
Author(s):  
Wenrui Qi ◽  
Danguang Pan ◽  
Yongtao Gao ◽  
Wenyan Lu ◽  
Ying Huang
Keyword(s):  
Fourier Transform ◽  
Fourier Series ◽  
Steady State ◽  
Frequency Domain ◽  
Imaginary Part ◽  
Complete Solution ◽  
Time History ◽  
Frequency Domain Method ◽  
Domain Method ◽  
Complex Damping

The conventional frequency domain method (CFDM) and dual-force-based time domain method (DTDM) are often used to solve the steady-state response of system with complex damping under an arbitrary force. However, the calculation efficiency of the DTDM is low due to the straightforward summation operation of series even if the solution of the DTDM is the exact real part of the solution. In addition, since the CFDM only can obtain the real part of solution not the complete solution, it gives misleading information that the solution does not have an imaginary part. In this paper, a fast frequency domain method (FFDM) is proposed to calculate the complete response of complex damping system including the imaginary part with a higher accuracy in a much faster manner. The new FFDM uses half of the Fourier series of the discrete Fourier transform of the actual arbitrary force to construct the Fourier series of the dual force, followed by calculating the time history response using the inverse fast Fourier transform. The new developed method is validated through three numerical examples with harmonic and seismic excitations. The numerical results show that the accuracy of the new FFDM is compatible to the DTDM but with much higher computational efficiency.

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