Characteristic model-based adaptive control for cryogenic wind tunnels

2020 ◽  
pp. 014233122096065
Author(s):  
Chenhui Yu ◽  
Fei Liao ◽  
Haibo Ji ◽  
Wenhua Wu
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Flow Field ◽  
Control Problem ◽  
Mimo System ◽  
Adaptive Controller ◽  
Characteristic Model ◽  
Model Based ◽  
Field Control ◽  
Cryogenic Wind Tunnel

With the increasing requirement of Reynolds number simulation in wind tunnel tests, the cryogenic wind tunnel is considered as a feasible method to realize high Reynolds number. Characteristic model-based adaptive controller design method is introduced to flow field control problem of the cryogenic wind tunnel. A class of nonlinear multi-input multi-output (MIMO) system is given for theoretical research that is related to flow field control of the cryogenic wind tunnel. The characteristic model in the form of second-order time-varying difference equations is provided to represent the system. A characteristic model-based adaptive controller is also designed correspondingly. The stability analysis of the closed loop system composed of the characteristic model or the exact discrete-time model and the proposed controller is investigated respectively. Numerical simulation is presented to illustrate the effectiveness of this control method. The modeling and control problem based on characteristic model method for a class of MIMO system are studied and first applied to the cryogenic wind tunnel control field.

Characteristic model–based adaptive controller with discrete extended state observer for servo systems

2017 ◽  
Vol 231 (4) ◽  
pp. 259-270 ◽  
Author(s):  
Xiang Wang ◽  
Yifei Wu ◽  
Enze Zhang ◽  
Jian Guo ◽  
Qingwei Chen
Keyword(s):  
Discrete Time ◽  
Adaptive Controller ◽  
State Observer ◽  
Lyapunov Theory ◽  
Extended State Observer ◽  
Recursive Least Squares ◽  
Extended State ◽  
Servo Systems ◽  
Characteristic Model ◽  
Model Based

Inertia variations and torque disturbances, most often considered as two of the major uncertainties in servo systems, highly affect the control performance. This article presents a characteristic model–based adaptive controller in the presence of large-range load inertia variations. A discrete-time characteristic model of the servo system, which has more advantages in describing time-varying dynamics, is established. The parameters of characteristic model are identified by a recursive least squares algorithm. To restrain the identification error and load torque disturbances, a discrete extended state observer is newly designed for the discrete-time system. Both the convergence of discrete extended state observer and the stability of closed-loop system are verified by the Lyapunov theory. Finally, simulation and experimental results demonstrate that the proposed controller provides better performance than the fuzzy proportional integral controller in terms of adaptability and robustness.

An Intermittent High-Reynolds-Number Wind Tunnel

1977 ◽  
Vol 28 (4) ◽  
pp. 259-264 ◽  
Author(s):  
J L Stollery ◽  
A V Murthy
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
High Reynolds Number ◽  
Reynolds Numbers ◽  
Simple Method ◽  
High Reynolds Numbers ◽  
Reservoir Conditions ◽  
High Reynolds ◽  
Cryogenic Wind Tunnel ◽  
Performance Estimates

SummaryThe paper suggests a simple method of generating intermittent reservoir conditions for an intermittent, cryogenic wind tunnel. Approximate performance estimates are given and it is recommended that further studies be made because this type of tunnel could be valuable in increasing the opportunities for research at high Reynolds numbers.

Temperature trajectory control of cryogenic wind tunnel with robust L1 adaptive control

2017 ◽  
Vol 40 (13) ◽  
pp. 3675-3689 ◽  
Author(s):  
Rusong Zhu ◽  
Guofu Yin ◽  
Gengsheng Tang ◽  
Hai Wang ◽  
Shuangxi Zhang
Keyword(s):  
Adaptive Control ◽  
Wind Tunnel ◽  
Temperature Control ◽  
Adaptive Controller ◽  
Linear Temperature ◽  
L1 Adaptive Control ◽  
State Dependent ◽  
Non Linear ◽  
Linear State ◽  
Cryogenic Wind Tunnel

Temperature control in a cryogenic wind tunnel is the key to realizing finely controlled Reynolds number close to true flight. This study deploys the L1 adaptive control methodology to ensure the total temperature profile of the cryogenic wind tunnel tracks a specified reference trajectory. After introducing a non-linear model of a cryogenic wind tunnel and a linear temperature model, a linear–quadratic–Gaussian (LQG) controller is implemented as the baseline controller. The L1 adaptive controller with piecewise constant adaptive law is used as an augmentation to the baseline controller to cancel the matched and unmatched uncertainties within the actuator’s bandwidth. By introducing two modifications to the standard L1 adaptive controller, which are the transportation delay modelling in the state predictor and the non-linear state dependent filter, the L1 adaptive controller improves the performance of the baseline controller in the presence of uncertainties in temperature control, guaranteeing proper stability and delay margin. The simulation results and analysis demonstrate the effectiveness of the proposed control architecture. The main contribution of this paper lies in the first applications of L1 adaptive control to the wind tunnel control problem and the non-linear state dependent filter in L1 adaptive control structure.

scholarly journals Reynolds number and wind tunnel wall effects on the flow field around a generic UHBR engine high-lift configuration

2020 ◽  
Vol 11 (4) ◽  
pp. 1009-1023 ◽  
Author(s):  
Junaid Ullah ◽  
Aleš Prachař ◽  
Miroslav Šmíd ◽  
Avraham Seifert ◽  
Vitaly Soudakov ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Flow Field ◽  
Test Section ◽  
Large Scale ◽  
Scale Model ◽  
Small Scale ◽  
Wall Effects ◽  
Tunnel Wall ◽  
High Lift

Abstract RANS simulations of a generic ultra-high bypass ratio engine high-lift configuration were conducted in three different environments. The purpose of this study is to assess small scale tests in an atmospheric closed test section wind tunnel regarding transferability to large scale tests in an open-jet wind tunnel. Special emphasis was placed on the flow field in the separation prone region downstream from the extended slat cut-out. Validation with wind tunnel test data shows an adequate agreement with CFD results. The cross-comparison of the three sets of simulations allowed to identify the effects of the Reynolds number and the wind tunnel walls on the flow field separately. The simulations reveal significant blockage effects and corner flow separation induced by the test section walls. By comparison, the Reynolds number effects are negligible. A decrease of the incidence angle for the small scale model allows to successfully reproduce the flow field of the large scale model despite severe wind tunnel wall effects.

High-Reynolds-Number Cryogenic Wind Tunnel

AIAA Journal ◽  
1973 ◽  
Vol 11 (5) ◽  
pp. 613-619 ◽  
Author(s):  
MICHAEL J. GOODYER ◽  
ROBERT A. KILGORE
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
High Reynolds Number ◽  
High Reynolds ◽  
Cryogenic Wind Tunnel

Blade Curve Influences on Performance of Savonius Rotors: Experimental and Numerical

2010 ◽  
Author(s):  
Ali Kianifar ◽  
Morteza Anbarsooz ◽  
Mohammad Javadi
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Wind Tunnel ◽  
Flow Field ◽  
Pressure Distribution ◽  
Power Coefficient ◽  
Blade Surface ◽  
Wind Tunnel Tests ◽  
Savonius Rotor ◽  
Circular Curves

In this study, the effect of blade curve on the power coefficient of a Savonius rotor is investigated by means of numerical simulation and wind tunnel tests. The tests were conducted on six rotors with identical dimensions but different blade curves, and the influences of blade curve and Reynolds number were studied. Followed by a simulation of the flow field around rotors with identical semi-circular curves and different overlaps, torque was calculated using pressure distribution on the blade surface, and the effect of Reynolds number and blade curve were studied on torque as well. Results indicate that changing the blade curve affects the power coefficient and torque by causing different drag coefficients. Also the rotor that yields the highest power coefficient and torque in one revolution compared with other rotors is highlighted.

Numerical Simulation of an Oscillating Cylinder at High Reynolds Number

2013 ◽  
Author(s):  
Simone Mandelli ◽  
Sara Muggiasca ◽  
Stefano Malavasi
Keyword(s):  
Reynolds Number ◽  
Wind Tunnel ◽  
Flow Field ◽  
High Reynolds Number ◽  
Fluid Dynamic ◽  
Numerical Results ◽  
Experimental Results ◽  
Dynamic Conditions ◽  
High Reynolds ◽  
Lock In

In this work a numerical investigation of the main flow field characteristics around a free oscillating rigid circular cylinder immersed in a turbulent flow is proposed (Re ≈ 5 · 104). The cylinder is characterized by high value of mass ratio and mass damping (m* = 145; ξ = 0.6 ÷ 1.14 · 10−3; m*ξ = 0.1 ÷ 0.25). The numerical results are compared with experimental data obtained in the wind tunnel under very similar fluid dynamic conditions. There are few works in literature that consider both numerical and experimental results under these conditions. This is probably due to the experimental facilities limitations and the computational difficulties correlated to modeling the flow at high Reynolds number. A numerical URANS model was developed through a CFD commercial code using a k–ω SST turbulence model in a 3D domain with the aim of matching the experimental results in the last years in the Politecnico di Milano Wind Tunnel on a suspended oscillating cylinder. The numerical setup is characterized by the use of the DFBI-Morphing (Dynamic Fluid Body Interaction) model that allows reproducing the body motion in response to fluid forces treating the cylinder as a mass-damping-spring system by introducing spring and damping forces acting on it. A preliminary check of this numerical setup was provided by a benchmark case involving a simple case of fixed cylinder at the same Reynolds number, where the movements of the cylinder were disabled. The numerical results of this case have been compared with experimental and numerical results reported in literature in terms of Drag and Lift coefficients and Strouhal number at high Reynolds numbers (Re ≈ 5 · 104). After that benchmark, the full setup has been checked by considering specific fluid dynamic conditions out of the lock in region in which the oscillations of the cylinder are negligible. Finally two points of the cylinder steady state response curve in the lock in region were investigated. The numerical model gave good results in terms of amplitude response of the cylinder and aerodynamic forces in agreement with experimental results. The analysis of the numerical reconstruction of the flow field evolution are therefore considered to have more information on the vortex shedding mode especially in the transition region between 2S and 2P mode.

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