Perturbation Analysis and Control of Mach Number 2.4-Meter Transonic Wind Tunnel

2020 ◽  
Vol 57 (6) ◽  
pp. 1148-1155
Author(s):  
Wenshan Yu ◽  
Ning Du ◽  
Zhengzhou Rao ◽  
Zhi Wei ◽  
Ping Yuan
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Perturbation Analysis ◽  
And Control ◽  
Transonic Wind Tunnel

scholarly journals Prediction of transients and control reactions in a transonic wind tunnel

2000 ◽  
Vol 22 (2) ◽  
pp. 317-339 ◽  
Author(s):  
João Batista Pessoa Falcão Filho ◽  
Marcos Aurélio Ortega ◽  
Luiz Carlos Sandoval Góes
Keyword(s):  
Wind Tunnel ◽  
And Control ◽  
Transonic Wind Tunnel

Interference Effects at Sonic Speeds for a Biconvex Aerofoil in a Wind Tunnel with Slotted Liners

1966 ◽  
Vol 70 (663) ◽  
pp. 446-448 ◽  
Author(s):  
W. J. Graham ◽  
A. G. J. MacDonald
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Static Pressure ◽  
Area Ratio ◽  
Interference Effects ◽  
Open Area ◽  
Sonic Speed ◽  
Reference Pressure ◽  
The Relationship ◽  
Transonic Wind Tunnel

The purpose of this note is to present some recently acquired data showing the effects of variations in the open area of slotted liners on the pressures on a twodimensional aerofoil at sonic speed in the 36 inch X 14 inch transonic wind tunnel at the NPL. The basic slotted liners for this tunnel have eleven longitudinal slots, giving an open-area ratio (σ) of 0.091. Other slot openings are obtained by closing appropriate slots with “Sellotape.” Nine values of σ ranging from 0 to 0.091, were used in this investigation. A wall static-pressure orifice, sufficiently far upstream of the model to be unaffected by its presence (3-6 chords), was used as a reference pressure for tunnel speed. The relationship between the Mach number given by this reference pressure and the true tunnel Mach number (M0), at the model location, was obtained by careful calibration.

scholarly journals Measurementimprovement of flow quality of slotted test section in transonic wind tunnel

2021 ◽  
Vol 39 (3) ◽  
pp. 660-667
Author(s):  
Shenghao Wu ◽  
Jiming Chen ◽  
Qin Chen ◽  
Haitao Pei
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Test Section ◽  
Experimental Studies ◽  
Flow Characteristics ◽  
Area Ratio ◽  
Straight Section ◽  
Flow Quality ◽  
Transonic Wind Tunnel

Experimental studies were carried out in the 0.6 m×0.6 m continuous transonic wind tunnel of CARDC in order to investigate the flow characteristics of the slotted test section. Experimental results show that the root-mean-square deviation of axial Mach number in the model area is above 0.01 when the test section Mach number is above 1.0.Numerical simulation under the same conditions to investigate the flow characteristics of the slotted section, together with the experimental studies indicate tow phenomena may directly cause the Mach number fluctuation. Firstly, a straight section was installed to connect the nozzle and the test section in the wind tunnel. Weak shock waves due to the curvature discontinuity at the joint of the test section and the straight section contribute to Mach number fluctuation. Secondly, the open-area ratio of both the upper and lower wall of test section, each with 8 slots, is of 10%. The larger porosity leads to stronger expansion waves in the acceleration zone located at the inlet of the test section. The flow was over accelerated because of the stronger expansion wave and thus fluctuate the flow field severely. Two measures were taken to improve the flow quality of the slotted test section based on the above-mentioned analysis: ①Flexible plate instead of solid straight plate was installed to bridge nozzle and test section to eliminate the curvature discontinuity; ②Decreasing the open-area ratio of the upper and lower test section wall to 6% and the number of slots to 6. Numerical and experimental results show that the Mach number fluctuation in the model area was suppressed to a satisfactory degree.

Heuristic open-loop output feedback model predictive control for control of intermittent transonic wind tunnel

2019 ◽  
Vol 42 (4) ◽  
pp. 832-839
Author(s):  
Jianchen Hu ◽  
Baocang Ding
Keyword(s):  
Steady State ◽  
Mach Number ◽  
Wind Tunnel ◽  
Predictive Control ◽  
Output Feedback ◽  
Total Pressure ◽  
Dynamic Control ◽  
Open Loop ◽  
Feedback Model ◽  
Transonic Wind Tunnel

For intermittent transonic wind tunnel (ITWT), Mach number and total pressure are crucial features of the flow field in the test section. However, they are typically difficult to control due to system nonlinearities, uncertainties, coupling and delays. This paper proposes an output feedback model predictive control (MPC) strategy to ensure the tracking of Mach number and total pressure of the ITWT to a specified reference trajectory. The proposed approach includes open-loop prediction, steady state target calculation (SSTC) and dynamic control, where the lower layer dynamic control tracks the steady state target obtained from the upper SSTC layer. By adding an artificial disturbance in the identified linear parameter varying (LPV) model for ITWT, and utilizing the resulting LPV model in both SSTC and dynamic control layers, a heuristic open-loop output feedback MPC approach is proposed. The experimental results for the control of Mach number and total pressure for ITWT demonstrate the effectiveness of the proposed approach.

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