Experimental Investigation of a 2D-circulation Controlled Cylinder in an Adaptive Wall Wind Tunnel PDF Download

Author: Fabrizio Adalberto Maria Dionisio
Publisher:
ISBN:
Category : Wind tunnels
Languages : en
Pages : 320

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Author: Roland Gunther Berndt
Publisher:
ISBN:
Category :
Languages : en
Pages : 266

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Author: Michael Joseph Bishop
Publisher:
ISBN:
Category :
Languages : en
Pages : 140

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Book Description
A renovation of an adaptive-wall wind tunnel was completed to improve flow quality, automate data acquisition, integrate a three-axis traversing mechanism, and regain functionality of an adaptive-wall test section. Redesign of the settling chamber significantly improved flow quality, with the resulting turbulence intensity of 0.3% and flow uniformity of ±0.6% matching characteristics of research-grade wind tunnels. The functionality of the adaptive-wall test section was tested by analyzing the effect of wall adaptation on flow development over a circular cylinder. Experiments were carried out for a Reynolds number (Red) of 57,000 for three blockage ratios: 5%, 8%, and 17%. Measurements were made in three wall configurations: geometrically straight walls (GSW), aerodynamically straight walls (ASW), and streamlined walls (SLW). Solid blockage effects were clearly evident in cylinder surface pressure distributions for the GSW and ASW configurations, manifested by an increased peak suction and base suction. Upon streamlining the walls, pressure distributions for each blockage ratio matched distributions expected for low blockage ratios. Wake blockage limited wake growth in the GSW configuration at 7.75 and 15 diameters downstream of the cylinder for blockages of 17% and 8%, respectively. This adverse effect was rectified by streamlining the walls with the resulting wake width development matching that expected for low blockage ratios. Wake vortex shedding frequency and shear layer instability frequency increased in the GSW and ASW configurations with increasing blockage ratio. Invariance of the near wake width with wall configuration suggests that frequency increase is caused by the increased velocity due to solid blockage effects. For all the blockage ratios investigated, the increased wake vortex shedding frequency observed in the ASW and GSW configurations was corrected in the SLW configuration, with the resulting Strouhal numbers of about 0.19, matching that expected for low blockage ratios at the investigated Red.

Author: Edward T. Schairer
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 40

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Author: Joel L. Everhart
Publisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 52

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Author: Zeki Celik
Publisher:
ISBN:
Category : Wall pressure (Aerodynamics)
Languages : en
Pages : 178

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Author: J. C Erickson (Jr)
Publisher:
ISBN:
Category :
Languages : en
Pages : 83

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Book Description
The results of a program of research on transonic wind tunnels with adaptive walls for eliminating wall interference are presented. A description is given of related experimental research performed at other laboratories using several alternative methods for controlling the flow. Features of the segmented- plenum, perforated-wall, two-dimensional test section of the Calspan One-Foot Tunnel and the associated instrumentation for measuring the flow disturbance quantities are reviewed and necessary modifications made to the original experimental configuration are described. Details of adaptive-wall iteration experiments with a 4%-blockage NACA 0012 airfoil model are presented, particularly those at a free-stream Mach number of 0.9 and nominal angles of attack of 3, 2 and 1 deg. In these experiments, regions of supercritical flow terminated by shock waves extended to the tunnel walls. The results of the experiments indicate that successful iterations toward interference-free flow conditions are achieved. For another phase of the research, conceptual design studies of a three-dimensional transonic adaptive-wall test section using the segmented-plenum, perforated-wall method of flow control are reported. Finally, numerical simulations of low-speed flow within the Calspan test section, including the interaction of the transpired boundary layer at the walls with the flow over the model, are described in AIAA Paper No. 81-0160, which is appended to the report.

Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 704

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Author: Chester D. Mayerson
Publisher:
ISBN:
Category :
Languages : en
Pages : 91

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Author: Jiaju He
Publisher:
ISBN:
Category :
Languages : en
Pages : 21

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Book Description
This article discusses the selection of the design parameters and the special structural points of the Northwestern Polytechnical Univ low speed, two-dimensional flexible wall self-streamlining wind tunnel. It also introduces the wind tunnel flow field operation, the self-streamlining iterative substitution design, the experimental operation programming, and the initial experimental results. As far as concerns the cylinder model with blockage ratio epsilon = 13.7% and the NACA0012 airfoil zero lift configuration with height to chord ratio of H/c = 1.28, after going through the process of 2-4 iterative substitutions in the self-streamlining model, it is even easier to get convergence and obtain a non-interference value which corresponds with the relevent reference materials and the self-correcting wind tunnels outside China. (Chinese translations).