Generalized nonlinear time-domain tracking control model for advanced technology telescopes

1990 ◽  
Author(s):  
Bobby L. Ulich ◽  
Kent P. Pflibsen ◽  
Chris Sheppard ◽  
Lonnie K. Calmes
Keyword(s):  
Time Domain ◽  
Tracking Control ◽  
Control Model ◽  
Advanced Technology ◽  
Nonlinear Time Domain

Nonlinear time-domain macromodeling of OTA circuits

2003 ◽  
Author(s):  
B. Perez-Verdu ◽  
J. Cruz ◽  
B. Linares-Barranco ◽  
A. Rodriguez-Vazquez ◽  
J.L. Huertas ◽  
...  
Keyword(s):  
Time Domain ◽  
Nonlinear Time Domain

Non-Linear Time and Frequency Domain Methods for Multi-Row Aeromechanical Analysis

2012 ◽  
Author(s):  
M. T. Rahmati ◽  
L. He ◽  
D. X. Wang ◽  
Y. S. Li ◽  
R. G. Wells ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Computational Models ◽  
Linear Time ◽  
Navier Stokes ◽  
Frequency Domain Method ◽  
Domain Method ◽  
Frequency Domain Methods ◽  
Blade Row ◽  
Nonlinear Time Domain

An unsteady Navier-Stokes solution system for aeromechanical analysis of multiple blade row configurations is presented. A distinctive feature of the solver is that unified numerical methods and boundary condition treatments are consistently used for both a nonlinear time-domain solution mode and a frequency-domain one. This not only enables a wider range of physical aeromechanical problems to be tackled, but also provides a consistent basis for validating different computational models, identifying and understanding their relative merits and adequate working ranges. An emphasis of the present work is on a highly efficient frequency-domain method for multi-row aeromechanic analysis. With a new interface treatment, propagations and reflections of pressure waves between adjacent blade rows are modeled within a domain consisting of only a single passage in each blade row. The computational model and methods are firstly described. Then, extensive validations of the frequency-domain method against both experimental data and the nonlinear time-domain solutions are described. Finally the computational analysis and demonstration of the intra-row reflection effects on the rotor aerodynamic damping are presented.

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