scholarly journals Geometric Effects Analysis and Verification of V-Shaped Support Interference on Blended Wing Body Aircraft

2020 ◽  
Vol 10 (5) ◽  
pp. 1596
Author(s):  
Xin Xu ◽  
Qiang Li ◽  
Dawei Liu ◽  
Keming Cheng ◽  
Dehua Chen
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Pitching Moment ◽  
Straight Section ◽  
Test Results ◽  
Wind Tunnel Tests ◽  
Blended Wing Body ◽  
Support Interference ◽  
Geometric Effects ◽  
Good Agreement

A special V-shaped support for blended wing body aircraft was designed and applied in high-speed wind tunnel tests. In order to reduce the support interference and explore the design criteria of the V-shaped support, interference characteristics and geometric parameter effects of V-shaped support on blended wing body aircraft were numerically studied. According to the numerical results, the corresponding dummy V-shaped supports were designed and manufactured, and verification tests was conducted in a 2.4 m × 2.4 m transonic wind tunnel. The test results were in good agreement with the numerical simulation. Results indicated that pitching moment of blended wing body aircraft is quite sensitive to the V-shaped support geometric parameters, and the influence of the inflection angle is the most serious. To minimize the pitching moment interference, the straight-section diameter and inflection angle should be increased while the straight-section length should be shortened. The results could be used to design special V-shaped support for blended wing body aircraft in wind tunnel tests, reduce support interference, and improve the accuracy of test results.

Using Wind Tunnel Tests for Slung-Load Clearance, Part 2: Other Loads

2014 ◽  
Vol 59 (4) ◽  
pp. 1-12
Author(s):  
Reuben Raz ◽  
Aviv Rosen ◽  
Luigi S. Cicolani ◽  
Jeffery Lusardi ◽  
Bryan Gassaway ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Flight Test ◽  
Test Results ◽  
Wind Tunnel Tests ◽  
Reduce Risk ◽  
Good Agreement

The first new load is the TRIO container that can be flown in three configurations with different heights. The second new load is a ribbon bridge interior bay section. Wind tunnel results with models of the new loads exhibit in general good agreement with flight-test results. The results of the new loads strengthen further the approach of using wind tunnel tests to accelerate slung-load clearance, as well as reduce risk and cost.

scholarly journals Wind Tunnel Testing of ONERA-M, AGARD-B and HB-2 Standard Models at Off-Design Conditions

Aerospace ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 275
Author(s):  
Dijana Damljanović ◽  
Đorđe Vuković ◽  
Goran Ocokoljić ◽  
Biljana Ilić ◽  
Boško Rašuo
Keyword(s):  
Wind Tunnel ◽  
Standard Test ◽  
Wind Tunnel Testing ◽  
Test Results ◽  
Technical Institute ◽  
Wind Tunnel Tests ◽  
Test Conditions ◽  
Standard Models ◽  
The Military ◽  
Good Agreement

Published results for standard wind tunnel models at non-standard test conditions are quite rare and/or may not be available. It has been found that those results are a useful aid in preparations for a number of wind tunnel tests in the Military Technical Institute (VTI) in Belgrade. Test campaigns of standard models at non-standard conditions are performed to serve as an internal database for future wind tunnel tests in such environments. Those tests, that partially overlap the referenced Mach number and/or angle of attack ranges, are conducted in different VTI’s test facilities; different model sizes and support stings were used. The standard models used in static measurements in VTI, ranging from simple missile shapes and re-entry bodies to complicated airplanes, are briefly described and sample non-standard test results are given. The correlation of the test results among models and facilities has been done with references in the available ranges, and, after confirming a good agreement, it is assumed that the results are also valid in the extended ranges of conditions. These results may be useful for researchers in other wind tunnel facilities and for those who handle CFD tools.

scholarly journals Experimental Results of Pitching Moment Tests on Parabolic-Trough Solar-Collector Array Configurations

1984 ◽  
Vol 106 (2) ◽  
pp. 223-230
Author(s):  
D. E. Randall ◽  
R. E. Tate ◽  
D. A. Powers
Keyword(s):  
Wind Tunnel ◽  
Solar Collector ◽  
Experimental Results ◽  
Pitching Moment ◽  
Test Results ◽  
Parabolic Trough ◽  
Wind Tunnel Tests ◽  
Array Configuration ◽  
Parabolic Trough Solar Collector ◽  
Shielding Effects

Two wind-tunnel tests were conducted to investigate specifically the pitching moment characteristics of parabolic-trough solar-collector modules deployed within a collector array. The collector modules were located within various rows of a simulated array configuration to investigate shielding effects from upstream collector rows and/or windscreen fences. Selected fence configurations and fence spacing upstream from the initial array row were studied. The test results demonstrate that pitching moment is significantly reduced by shielding provided by upstream fencing or collector rows.

scholarly journals Cable Suspension and Balance System with Low Support Interference and Vibration for Effective Wind Tunnel Tests

2021 ◽  
Author(s):  
Keum-Yong Park ◽  
Yeol-Hun Sung ◽  
Jae-Hung Han
Keyword(s):  
Wind Tunnel ◽  
Vibration Suppression ◽  
Aerodynamic Load ◽  
Test Model ◽  
Wind Tunnel Tests ◽  
Balance System ◽  
Motion Responses ◽  
Vibration Responses ◽  
Aerodynamic Interference ◽  
Support Interference

AbstractA cable-driven model support concept is suggested and implemented in this paper. In this case, it is a cable suspension and balance system (CSBS), which has the advantages of low support interference and reduced vibration responses for effective wind tunnel tests. This system is designed for both model motion control and aerodynamic load measurements. In the CSBS, the required position or the attitude of the test model is realized by eight motors, which adjust the length, velocity, and acceleration of the corresponding cables. Aerodynamic load measurements are accomplished by a cable balance consisting of eight load cells connected to the assigned cables. The motion responses and load measurement outputs were in good agreement with the reference data. The effectiveness of the CSBS against aerodynamic interference and vibration is experimentally demonstrated through comparative tests with a rear sting and a crescent sting support (CSS). The advantages of the CSBS are examined through several wind tunnel tests of a NACA0015 airfoil model. The cable support of the CSBS clearly showed less aerodynamic interference than the rear sting with a CSS, judging from the drag coefficient profile. Additionally, the CSBS showed excellent vibration suppression characteristics at all angles of attack.

scholarly journals Numerical Analysis of Vibration Responses in High-Speed Railways considering Mud Pumping Defect

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Ting Li ◽  
Qian Su ◽  
Kang Shao ◽  
Jie Liu
Keyword(s):  
High Speed ◽  
Coupled Model ◽  
Test Results ◽  
External Excitation ◽  
Slab Track ◽  
Vibration Responses ◽  
Track Irregularity ◽  
Mud Pumping ◽  
Element Theory ◽  
Good Agreement

As a newly appeared defect under slab tracks in high-speed railways, mud pumping weakens the support ability of the subgrade to slab track, bringing about deviations on the vibration responses of the vehicle, slab track, and subgrade. Therefore, this paper proposes a vehicle-slab track-subgrade coupled model based on the multibody simulation principle and the finite element theory to highlight the influences of mud pumping defect. As an external excitation to this model, random track irregularity is considered. In order to simulate the mud pumping defect, the contact between the concrete base and subgrade is described as a spring-damper system. This model is validated by field test results and other simulation results, and a very good agreement is found. The vibration responses of the vehicle, slab track, and subgrade under different mud pumping lengths and train speeds are studied firstly. The deviations of vibration responses in high-speed railways induced by mud pumping are then obtained, and the limited mud pumping length is put forward finally to provide a recommendation for maintenance works of high-speed railways in practice.

Preparation and execution of the NICETRIP low- and high-speed wind tunnel tests

2016 ◽  
Vol 7 (2) ◽  
pp. 167-184
Author(s):  
O. Schneider ◽  
M. Przybilla ◽  
E. Brehl ◽  
H. Mainz ◽  
Y. Govers ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Wind Tunnel Tests

scholarly journals A technique to predict the aerodynamic effects of battle damage on an aircraft’s wing

2015 ◽  
Vol 119 (1218) ◽  
pp. 937-960 ◽  
Author(s):  
T.W. Pickhaver ◽  
P.M. Render
Keyword(s):  
Wind Tunnel ◽  
Lower Surface ◽  
Surface Flow ◽  
Internal Cavity ◽  
Flow Visualisation ◽  
Pitching Moment ◽  
Wind Tunnel Tests ◽  
Tunnel Model ◽  
Circular Holes ◽  
The Difference

Abstract A technique is developed that can be used to predict the effects of battle damage on the aerodynamic performance of an aircraft’s wing. The technique is based on results obtained from wind tunnel tests on a NASA LS(1)-0417MOD aerofoil with simulated gunfire damage. The wind tunnel model incorporated an internal cavity to represent typical aircraft construction and this was located between 24% and 75% of chord. The damage was simulated by circular holes with diameters between 20% and 40% of chord. To represent different attack directions, the inclination of the hole axis relative to the aerofoil chord was varied between ±60° pitch and 45° of roll. The aerofoil spanned the wind tunnel to create approximate two-dimensional conditions and balance measurements were carried out at a Reynolds number of 500,000 for incidences, increased in 2° increments, from –4° to 16°. Surface flow visualisation and pressure measurements were also carried out. For a given hole size, the increments in lift, drag and pitching moment coefficients produced trends when plotted against the difference between the upper and lower surface pressure coefficients on the undamaged aerofoil taken at the location of the damage. These trends are used as the basis of the predictive technique. The technique is used to predict the effects of a previously untested damage case, and these are compared with wind tunnel tests carried out on a half model finite aspect ratio wing. For all coefficients the trends in the predicted data are similar to experiment, although there are some discrepancies in absolute values. For the drag coefficient these discrepancies are partly accounted for by limitations in the technique, whilst discrepancies in the lift and pitching moment coefficients are attributed to limitations in the aerofoil test arrangements.

The Effect of Cross-Winds on Trains

1981 ◽  
Vol 103 (1) ◽  
pp. 170-178 ◽  
Author(s):  
R. K. Cooper
Keyword(s):  
Wind Tunnel ◽  
Model Experiment ◽  
High Speed ◽  
Wind Tunnel Tests ◽  
Turbulent Wind ◽  
Wind Speeds ◽  
High Speed Trains ◽  
Low Mass

Low mass, high speed trains may be in danger of being overturned by strong crosswinds. This paper examines the aerodynamic data required to estimate overturning wind speeds. The results of wind tunnel tests and a moving model experiment, including the effect of the turbulent wind, are described.

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