scholarly journals UNCERTAINTY IN STATIC PRESSURE CORRECTION IN A SUBSONIC WIND TUNNEL

2004 ◽  
Vol 3 (2) ◽  
Author(s):  
M. L. C. C. Reis ◽  
O. A. F. Mello ◽  
M. Chisaki
Keyword(s):  
Wind Tunnel ◽  
Static Pressure ◽  
Uncertainty Propagation ◽  
Wind Tunnel Test ◽  
Absolute Pressure ◽  
Input Quantity ◽  
Flow Parameters ◽  
Subsonic Wind Tunnel ◽  
Measured Flow ◽  
The One

The static pressure p on the subsonic Wind Tunnel of the Aerodynamic Testing Laboratory of the Institute of Aeronautics and Space – IAE, Aerospace Technical Center – CTA, is measured using an absolute pressure sensor, located on the upper test section wall. This measurement is not taken at the same location as the one where the model is mounted during the actual wind tunnel test. This fact raises the need for a correction during data reduction. The identification and evaluation of the associated error source is important because the static pressure is an input quantity for the calculation of the total pressure pt, Mach number M and density ρ during the test. The present paper is concerned with the determination of the relationship between the static pressure measured on the tunnel’s upper wall and that at the model location, and with the analysis of the uncertainty propagation for the measured flow parameters.

scholarly journals UNCERTAINTY IN STATIC PRESSURE CORRECTION IN A SUBSONIC WIND TUNNEL

2004 ◽  
Vol 3 (2) ◽  
pp. 122
Author(s):  
M. L. C. C. Reis ◽  
O. A. F. Mello ◽  
M. Chisaki
Keyword(s):  
Wind Tunnel ◽  
Static Pressure ◽  
Wind Tunnel Test ◽  
Absolute Pressure ◽  
Input Quantity ◽  
Flow Parameters ◽  
Subsonic Wind Tunnel ◽  
Measured Flow ◽  
The One

The static pressure p on the subsonic Wind Tunnel of the Aerodynamic Testing Laboratory of the Institute of Aeronautics and Space – IAE, Aerospace Technical Center – CTA, is measured using an absolute pressure sensor, located on the upper test section wall. This measurement is not taken at the same location as the one where the model is mounted during the actual wind tunnel test. This fact raises the need for a correction during data reduction. The identification and evaluation of the associated error source is important because the static pressure is an input quantity for the calculation of the total pressure pt, Mach number M and density ρ during the test. The present paper is concerned with the determination of the relationship between the static pressure measured on the tunnel’s upper wall and that at the model location, and with the analysis of the uncertainty propagation for the measured flow parameters.

Aerodynamic Interference Correction Methods Case: Subsonic Closed Wind Tunnels

2012 ◽  
Vol 225 ◽  
pp. 60-66 ◽  
Author(s):  
Surjatin Wiriadidjaja ◽  
Azmin Shakrine Mohd Rafie ◽  
Fairuz Izzuddin Romli ◽  
Omar Kassim Ariff
Keyword(s):  
Wind Tunnel ◽  
Classical Method ◽  
Wind Tunnel Test ◽  
Analytical Techniques ◽  
Wind Tunnels ◽  
New Techniques ◽  
Subsonic Wind Tunnel ◽  
Small Model ◽  
Active Research ◽  
Solid Walls

The approach to problems of wall interference in wind tunnel testing is generally based on the so-called classical method, which covers the wall interference experienced by a simple small model or the neo-classical method that contains some improvements as such that it can be applied to larger models. Both methods are analytical techniques offering solutions of the subsonic potential equation of the wall interference flow field. Since an accurate description of wind tunnel test data is only possible if the wall interference phenomena are fully understood, uncounted subsequent efforts have been spent by many researchers to improve the limitation of the classical methods by applying new techniques and advanced methods. However, the problem of wall interference has remained a lasting concern to aerodynamicists and it continues to be a field of active research until the present. The main objective of this paper is to present an improved classical method of the wall interference assessment in rectangular subsonic wind tunnel with solid-walls.

Wind Tunnel Test of a Blended Wing Aircraft in Ground Effect With Active Flow Control

2016 ◽  
Author(s):  
Michael Mayo ◽  
Jonathan Carroll ◽  
Nicholas Motahari ◽  
Warren Lee ◽  
Robert Englar
Keyword(s):  
Wind Tunnel ◽  
Active Flow Control ◽  
Wind Tunnel Test ◽  
Ground Effect ◽  
Circulation Control ◽  
Wing Model ◽  
Subsonic Wind Tunnel ◽  
Test Methodology ◽  
Tunnel Floor ◽  
Lift And Drag

This paper describes the test methodology and results for a wind tunnel experiment featuring a blended wing aircraft in ground effect with built-in circulation control. A 82.55cm wingspan blended wing model was tested in a subsonic wind tunnel at velocities ranging from 18m/s – 49m/s and corresponding Reynolds numbers ranging from 130k – 350k. Pitch angle was held constant at 0 degrees and the height above the wind tunnel floor was modified to determine lift and drag modification due to ground effect. At a normalized height (y/bw) of 0.06, ground effect increased lift production by 24% and reduced drag by 22% when compared to a normalized height of 0.5. The addition of the circulation control significantly increased the lift production of the model at a cost of increased drag. At a normalized height of 0.031, the lift production increased by 200% at a blowing coefficient of 0.01, but the drag also increased by 72%, ultimately increasing L/D by 178%. Experimental results also suggest that ground effect and circulation control have a synergistic effect when used simultaneously. The effects of Reynolds number and circulation control slot height are also investigated.

The Test Study of Shape Coefficient of Low-Rise Buildings Roof with Different Positions of Openings

2012 ◽  
Vol 446-449 ◽  
pp. 3092-3095
Author(s):  
Ji Zhou ◽  
Yuan Ming Dou ◽  
Xi Yuan Liu ◽  
Ji Shu Sun
Keyword(s):  
Wind Tunnel ◽  
Pressure Measurement ◽  
Wind Tunnel Test ◽  
Wind Pressure ◽  
Wind Damage ◽  
Building Roof ◽  
Wind Resistance ◽  
Shape Coefficient ◽  
Test Study ◽  
The One

The majority of low-rise buildings are generally susceptible to wind damage in previous wind disaster, thus it is necessary to gain understanding of the characteristics of wind pressure for these types of building. Based on Wind Tunnel Test, the shape coefficients were studied with pressure measurement on gable roofs laying aside purlin of low-rise building roof in this paper. Three aspects were arerespectively discussed: the lows of shape coefficients and the shape coefficient value with specific wind angle on roofs of the houses completely closed, the house opened doors and windows and the house opened the hole on roof with different wind angle. The laws of shape coefficients were propounded for low-rise buildings with different positions of openings in contrast to load code. A detailed analysis of the experimental results shows that the shape coefficients will increase notably when there are the openings on metope and on roof, and the one is outward of roof, another is inward of roof. It is expected that the results should be valuable for the wind-resistance design of low-rise buildings.

scholarly journals Wind tunnel testing of powered lift, all-wing STOL model

2009 ◽  
Vol 113 (1140) ◽  
pp. 129-137 ◽  
Author(s):  
S. W. Collins ◽  
B. W. Westra ◽  
J. C. Lin ◽  
G. S. Jones ◽  
C. H. Zeune
Keyword(s):  
Wind Tunnel ◽  
State Of The Art ◽  
Wind Tunnel Test ◽  
Field Measurements ◽  
Wind Tunnel Testing ◽  
High Lift ◽  
Computational Tools ◽  
Subsonic Wind Tunnel ◽  
Model Configuration ◽  
Langley Research Center

Abstract Short take-off and landing (STOL) systems can offer significant capabilities to warfighters and, for civil operators thriving on maximising efficiencies they can improve airspace use while containing noise within airport environments. In order to provide data for next generation systems, a wind tunnel test of an all-wing cruise efficient, short take-off and landing (CE STOL) configuration was conducted in the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC) 14ft by 22ft Subsonic Wind Tunnel. The test’s purpose was to mature the aerodynamic aspects of an integrated powered lift system within an advanced mobility configuration capable of CE STOL. The full-span model made use of steady flap blowing and a lifting centerbody to achieve high lift coefficients. The test occurred during April through June of 2007 and included objectives for advancing the state-of-the-art of powered lift testing through gathering force and moment data, on-body pressure data, and off-body flow field measurements during automatically controlled blowing conditions. Data were obtained for variations in model configuration, angles of attack and sideslip, blowing coefficient, and height above ground. The database produced by this effort is being used to advance design techniques and computational tools for developing systems with integrated powered lift technologies.

Wind Tunnel Test of Effect of Sound-Absorbing Material on Lift of Two-Element Airfoil

2013 ◽  
Vol 830 ◽  
pp. 17-23
Author(s):  
Yong Wei Gao ◽  
Qi Liang Zhu ◽  
Long Wang
Keyword(s):  
Wind Tunnel ◽  
High Frequency ◽  
Lift Coefficient ◽  
Wind Tunnel Test ◽  
Low Frequency ◽  
Leading Edge ◽  
Aerodynamic Characteristics ◽  
Fluctuating Pressure ◽  
Flow Parameters ◽  
Absorbing Material

The flow parameters of fluctuating pressure and fluctuating velocity in the gap can be changed by the porous absorption material on the leading edge of upper surface of the flap of multi-element airfoil (GAW-1),and the aerodynamic characteristics is also altered. Experiment was conducted in the NF-3 wind tunnel. It turns out that porous absorption material has a significant effect on fluctuating velocity (i.e. turbulent kinetic energy), and the lift coefficient drops when fluctuating velocity increases ; but the influence on RMS of fluctuating pressure on upper surface is not obvious; the average speed in gap is reduced. The PSD of fluctuating pressure and fluctuating velocity show that low-frequency signal has a more obvious influence on lift of multi-element airfoils than high-frequency.

Wind Tunnel Test on Cable Dome of Geiger Type

2007 ◽  
Vol 2 (3) ◽  
pp. 218-224 ◽  
Author(s):  
Zhi-hong Zhang ◽  
Yukio Tamura
Keyword(s):  
Wind Tunnel ◽  
Dynamic Instability ◽  
Wind Tunnel Test ◽  
Harmonic Excitation ◽  
Degree Of Freedom ◽  
Shaking Table ◽  
Frequency Components ◽  
The One ◽  
Cable Dome ◽  
Cauchy Number

This paper presents preliminary results of an aeroelastic wind tunnel test on a cable dome. The structural design of the model is given in detail. Similarity requirements based on dimensional analysis are discussed, including Froude number, Cauchy number, and Scruton number. Structural tests are conducted on the aeroelastic model. Dynamic instability subject to harmonic excitation like a single-degree-of-freedom hardening system is verified. Both odd and even frequency components are excited when the shaking table shakes at 29Hz. For the one-degree-of-freedom Duffing model, even frequency components will be impossible due to the symmetry of the motion equation if symmetry-breaking bifurcation behaviors do not occur. Phase plane is checked and discussed when the shaking table shakes at 7Hz. A strange attractor appears to exist on the basis of the Poincare map. Some statistical results of wind tunnel tests are presented. The possibility of aeroelastic instability of the cable dome is discussed.

scholarly journals A preliminary study on static pressure probe mobile measurement method for flow field in transonic wind tunnel

2021 ◽  
Vol 39 (4) ◽  
pp. 786-793
Author(s):  
Haijun Deng ◽  
Bo Xiong ◽  
Xinfu Luo ◽  
Shaozun Hong ◽  
Qi Liu ◽  
...  
Keyword(s):  
Mach Number ◽  
Wind Tunnel ◽  
Flow Field ◽  
Static Pressure ◽  
Wind Tunnel Test ◽  
Flow Characteristics ◽  
Pressure Probe ◽  
Number Distribution ◽  
Mach Number Distribution ◽  
Transonic Wind Tunnel

The axial Mach number distribution of the core flow for model in a transonic wind tunnel is an important index to evaluate the performance of the flow field, which is usually measured by the centerline probe. In order to simulate the incoming flow characteristics without interference, the probe will extend from the support section to the shrinkage section, so the probe usually must has longer inches, more static pressure measuring points and smaller blockage requirements. In order to study the influence of the points of the centerline probe on the uniformity distribution of flow field, a new static pressure probe is designed, which is smaller and shorter than the centerline probe. On the basis of the stability of the flow field, the Mach number distribution of the flow field measured by the static pressure probe which is driven by the moving measuring mechanism. The characteristics of the measured values are studied by wind tunnel test. The results show that: when Ma ≤ 0.95, the overall distribution and value of Mach number obtained by the static pressure probe is basically the same as those obtained by the centerline probe, but some flow field details, which mainly shows that Mach number of the static pressure probe has smaller fluctuation, higher accuracy and better uniformity index.

Wind Tunnel Test and Wind Effects on Cable Dome

2006 ◽  
Author(s):  
Zhi-hong Zhang ◽  
Yukio Tamura
Keyword(s):  
Wind Tunnel ◽  
Dynamic Instability ◽  
Wind Tunnel Test ◽  
Harmonic Excitation ◽  
Shaking Table ◽  
Aeroelastic Model ◽  
Frequency Components ◽  
The One ◽  
Cable Dome ◽  
Cauchy Number

This paper presents preliminary results of an aeroelastic wind tunnel test on a cable dome. The structural design of the model is given in detail. Similarity requirements based on dimensional analysis are discussed, including Froude number, Cauchy number and Scruton number. Structural tests are conducted on the aeroelastic model. Dynamic instability subject to harmonic excitation like SDOF hardening system is verified. Both odd and even frequency components are excited when the shaking table dowels at 29Hz. For the one-degree-of-freedom Duffing model, even frequency components will be impossible due to the symmetry of the motion equation if symmetry-breaking bifurcation behaviors do not occur. Phase plane is checked and discussed when the shaking table dowels at 7Hz. A strange attractor is found from Poincare map. Some statistical results of wind tunnel tests are presented. The possibility of aeroelasic instability of the cable dome is discussed.

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