Surface Mounted Flow State Estimation of Reduced Order POD Models: Shear Layer

2010 ◽  
Author(s):  
Casey Fagley ◽  
Mark Balas ◽  
Jurgen Seidel ◽  
Stefan Siegel ◽  
Thomas Mclaughlin
Keyword(s):  
Shear Layer ◽  
State Estimation ◽  
Flow State ◽  
Reduced Order

State Estimation Using a Reduced-Order Kalman Filter

2001 ◽  
Vol 58 (23) ◽  
pp. 3666-3680 ◽  
Author(s):  
Brian F. Farrell ◽  
Petros J. Ioannou
Keyword(s):  
Kalman Filter ◽  
State Estimation ◽  
Reduced Order

scholarly journals State Estimation with Reduced-Order Observer and Adaptive-LQR Control of Time Varying Linear System

2020 ◽  
Vol 26 (2) ◽  
pp. 24-31
Author(s):  
Omer Aydogdu ◽  
Mehmet Latif Levent
Keyword(s):  
Optimal Control ◽  
Linear System ◽  
State Estimation ◽  
Servo System ◽  
Variable Load ◽  
Time Varying ◽  
Load Effect ◽  
Reduced Order ◽  
Lqr Control ◽  
Reduced Order Observer

In this study, a new controller design was created to increase the control performance of a variable loaded time varying linear system. For this purpose, a state estimation with reduced order observer and adaptive-LQR (Linear–Quadratic Regulator) control structure was offered. Initially, to estimate the states of the system, a reduced-order observer was designed and used with LQR control method that is one of the optimal control techniques in the servo system with initial load. Subsequently, a Lyapunov-based adaptation mechanism was added to the LQR control to provide optimal control for varying loads as a new approach in design. Thus, it was aimed to eliminate the variable load effects and to increase the stability of the system. In order to demonstrate the effectiveness of the proposed method, a variable loaded rotary servo system was modelled as a time-varying linear system and used in simulations in Matlab-Simulink environment. Based on the simulation results and performance measurements, it was observed that the proposed method increases the system performance and stability by minimizing variable load effect.

scholarly journals CFD Simulation of Flow Tones From Grazing Flow Past a Deep Cavity

2006 ◽  
Author(s):  
Ted G. Bagwell
Keyword(s):  
Shear Layer ◽  
Cfd Simulation ◽  
Stokes Equations ◽  
Weak Interactions ◽  
Cavity Resonator ◽  
Navier Stokes ◽  
Flow State ◽  
Deep Cavity ◽  
Eddy Simulation ◽  
Lock In

Locked-in flow tones due to shear flow over a deep cavity are investigated using Large Eddy Simulation (LES). An isentropic from of the compressible Navier-Stokes equations (pseudo-compressibility) is used to couple the vertical flow over the cavity mouth with the deep cavity resonances (1). Comparisons to published experimental data (2) show that the pseudo-compressible LES formulation is capable of predicting the feedforward excitation of the deep cavity resonator, as well as the feedback process from the resonator to the flow source. By systematically increasing the resonator damping level, it is shown that strong lock-in results in a more organized shear layer than is observed for the locked-out flow state. By comparison, weak interactions (non-locked-in) produce no change in the shear layer characteristics. This supports the 40 dB definition of lock-in defined in the experiment.

Reduced Order Modelling of Combustion Instability in a Backward Facing Step Combustor

2013 ◽  
Author(s):  
C. Vamsi Krishna ◽  
Santosh Hemchandra
Keyword(s):  
Stability Analysis ◽  
Shear Layer ◽  
Phase Speed ◽  
Advection Equation ◽  
Destructive Interference ◽  
Flame Surface ◽  
Backward Facing Step ◽  
Combustion Dynamics ◽  
Reduced Order ◽  
Reduced Order Modelling

This paper develops a fully coupled time domain Reduced Order Modelling (ROM) approach to model unsteady combustion dynamics in a backward facing step combustor. The acoustic field equations are projected onto the canonical acoustic eigenmodes of the systems to obtain a coupled system of modal evolution equations. The heat release response of the flame is modelled using the G-equation approach. Vortical velocity fluctuations that arise due to shear layer rollup downstream of the step are modelled using a simplified 1D-advection equation whose phase speed is determined from a linear, local, temporal stability analysis of the shear layer, just downstream of the step. The hydrodynamic stability analysis reveals a abrupt change in the value of disturbance phase speed from unity for Re < Recrit to 0.5 for Re > Recrit, where Recrit for the present geometry was found to be ≈ 10425. The results for self-excited flame response show highly wrinkled flame shapes that are qualitatively similar to those seen in prior experiments of acoustically forced flames. The effect of constructive and destructive interference between the two contributions to flame surface wrinkling results in high amplitude wrinkles for the case when Kc → 1.

scholarly journals Reduced-order state estimation for linear time-varying systems

2009 ◽  
Vol 11 (6) ◽  
pp. 595-609
Author(s):  
In Sung Kim ◽  
Bruno O. S. Teixeira ◽  
Jaganath Chandrasekar ◽  
Dennis S. Bernstein
Keyword(s):  
State Estimation ◽  
Linear Time ◽  
Time Varying ◽  
Reduced Order ◽  
Time Varying Systems ◽  
Order State
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