scholarly journals Aerodynamic study of a suspension bridge deck by CFD simulations, wind tunnel tests and full-scale observations

2021 ◽  
Vol 1201 (1) ◽  
pp. 012007
Author(s):  
I. Kusano ◽  
E. Cheynet ◽  
J. B. Jakobsen ◽  
J. Snæbjörnsson
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Suspension Bridge ◽  
Aerodynamic Characteristics ◽  
Full Scale ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Wide Range

Abstract Assessing the aerodynamic characteristics of long-span bridges is fundamental for their design. Depending on the terrain complexity and local wind conditions, episodes of large angles of attack (AoA) of 15° may be observed. However, such large AoAs ( above 10°) are often overlooked in the design process. This paper studies the aerodynamics properties of a flow around a single-box girder for a wide range of AoAs, from –20° to 20°, using numerical simulations. The simulations are based on a 2D unsteady Reynolds-averaged Navier–Stokes (URANS) approach using the k − ω SST turbulence model with a Reynolds number of 1.6 × 105. Numerically obtained aerodynamic static coefficients were compared to wind tunnel test data. The CFD results were generally in good agreement with the wind tunnel tests, especially for small AoAs and positive AoAs. More discrepancies were observed for large negative AoA, likely due to the limitation of modelling 3D railings with 2D simulations. The simulated velocity deficit downstream of the deck was consistent with the one measured in full-scale using short-range Doppler wind lidar instruments. Finally, the Strouhal number from the CFD simulations were in agreement with the value obtained from the full-scale data.

Pressure Distributions on Sails Investigated Using Three Methods: On-Water Measurements, Wind-Tunnel Measurements, and Computational Fluid Dynamics

2011 ◽  
Author(s):  
Ignazio Maria Viola ◽  
Richard G. J. Flay
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Full Scale ◽  
Navier Stokes ◽  
Pressure Measurements ◽  
Wind Tunnel Tests ◽  
Pressure Distributions ◽  
Unstable Environment ◽  
Full Scale Tests ◽  
Good Agreement

The main results of a two-year project aimed at comparing full-scale tests, wind tunnel tests, and numerical analysis predictions are presented. Pressure measurements were obtained from both full-scale tests and wind-tunnel tests, in upwind and downwind conditions. The upwind wind tunnel test condition was modelled using a Vortex Lattice code, while the downwind wind-tunnel test was modelled using a Navier-Stokes code. The pressures obtained from the three different methods are compared on three horizontal sections of the headsail, mainsail, and asymmetric spinnaker. In general the pressures from the three experiments showed good agreement. In particular, very good agreement was obtained between the numerical computations and the wind tunnel test results. Conversely, the results from the downwind full-scale pressure measurements showed less similarity due to a slightly tightened trim being used for the spinnaker in the on-water tests. Full-scale tests allow the action of unsteadiness due to the wind, wave and yacht movements to affect the results. This unstable environment caused the asymmetric spinnaker to move around, and a tightened trim was required to prevent the spinnaker from collapsing.

Wind Tunnel Experimental Research on Flutter Stability of Liujiaxia Bridge

2013 ◽  
Vol 361-363 ◽  
pp. 1105-1109
Author(s):  
Chun Sheng Shu
Keyword(s):  
Wind Tunnel ◽  
Critical Velocity ◽  
Experimental Research ◽  
Wind Tunnel Test ◽  
Suspension Bridge ◽  
Wind Tunnel Tests

Liujiaxia Bridge is a truss stiffening girder suspension bridge which span is 536m, and it is the narrowest suspension bridge with the same scale, so the problems of flutter stability are prominent. Results of wind tunnel test show that its critical velocity cannot meet the requirements without any aerodynamic measures. Based on above considerations, seven kinds of aerodynamic measures are proposed, respectively wind tunnel tests are conducted. The results show that the program, in which the upper central stable board is 1.12m high and the under central stable board is 1.28m high, can meet the requirements. The results of this study provide some references to solving the problem of wind-resistant stability of narrow deck suspension bridge.

Flutter mitigation of a superlong-span suspension bridge with a double-deck truss girder through wind tunnel tests

2020 ◽  
pp. 107754632094615
Author(s):  
Yanguo Sun ◽  
Yongfu Lei ◽  
Ming Li ◽  
Haili Liao ◽  
Mingshui Li
Keyword(s):  
Wind Tunnel ◽  
Damping Ratio ◽  
Suspension Bridge ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Long Span ◽  
Upper Deck ◽  
Torsional Damping ◽  
And Control ◽  
Wind Induced Vibration

As flutter is a very dangerous wind-induced vibration phenomenon, the mitigation and control of flutter are crucial for the design of long-span bridges. In the present study, via a large number of section model wind tunnel tests, the flutter performance of a superlong-span suspension bridge with a double-deck truss girder was studied, and a series of aerodynamic and structural measures were used to mitigate and control its flutter instability. The results show that soft flutter characterized by a lack of an evident divergent point occurred for the double-deck truss girder. Upper central stabilizers on the upper deck, lower stabilizers below the lower deck, and horizontal flaps installed beside the bottoms of the sidewalks are all effective in suppressing flutter for this kind of truss girder. By combining the structural design with aerodynamic optimizations, a redesigned truss girder with widened upper carriers and sidewalks, and double lower stabilizers combined with the inspection vehicle rails is identified as the optimal flutter mitigation scheme. It was also found that the critical flutter wind speed increases with the torsional damping ratio, indicating that the dampers may be efficient in controlling soft flutter characterized by single-degree-of-freedom torsional vibration. This study aims to provide a useful reference and guidance for the flutter design optimization of long-span bridges with double-deck truss girders.

Study on the Aerodynamic Characteristics and Galloping Instability of Conductors Covered with Sector-Shaped Ice by a Wind Tunnel Test

2020 ◽  
Vol 20 (06) ◽  
pp. 2040016
Author(s):  
Jia-Xiang Li ◽  
Jian Sun ◽  
Ye Ma ◽  
Shu-Hong Wang ◽  
Xing Fu
Keyword(s):  
Wind Tunnel ◽  
Drag Coefficient ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Ice Thickness ◽  
Shape Parameters ◽  
Aerodynamic Coefficient ◽  
Wind Tunnel Tests ◽  
And Control

Conductors with sector-shaped ice are susceptible to galloping. To prevent and control galloping, it is necessary to study the conductor aerodynamic characteristics. Wind tunnel tests were performed to study the influence of two shape parameters (ice thickness and ice angle) of a conductor with sector-shaped ice on the aerodynamic characteristics considering the roughness of the surface. In addition, the unstable areas for galloping are discussed according to Den Hartog theory and Nigol theory. The results show that with increasing ice thickness, the aerodynamic coefficient curves fluctuate more strongly, and galloping tends to occur; with increasing ice angle, the unstable area becomes larger according to Nigol theory, and the increasing drag coefficient will suppress the unstable areas according to Den Hartog theory. With the increasing two shape parameters, the most affected ranges of the aerodynamic coefficient curves are 150–180∘.

scholarly journals Wind Tunnel Tests of Influence of Boosters and Fins on Aerodynamic Characteristics of the Experimental Rocket Platform

2017 ◽  
Vol 2017 (4) ◽  
pp. 82-102
Author(s):  
Paweł Ruchała ◽  
Robert Placek ◽  
Wit Stryczniewicz ◽  
Jan Matyszewski ◽  
Dawid Cieśliński ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Drag ◽  
Wind Tunnel Test ◽  
Longitudinal Axis ◽  
Aerodynamic Characteristics ◽  
Scale Model ◽  
Wind Tunnel Tests ◽  
Aerodynamic Loads ◽  
Microgravity Experiments ◽  
Image Velocimetry

Abstract The paper presents results of wind tunnel tests of the Experimental Rocket Platform (ERP), which is developed in Institute of Aviation. It is designed as an easy accessible and affordable platform for microgravity experiments. Proposed design enables to perform experiments in microgravity for almost 150 seconds with apogee of about 100 km. The full-scale model of the ERP has been investigated in the T-3 wind tunnel in Institute of Aviation. During the investigation, the aerodynamic loads of the rocket has been measured for the angle of attack up to 10° and the different rotation angle around the longitudinal axis (up to 90°, depending on the configuration). Three configurations has been investigated: • without fins and boosters • with fins and without boosters • with fins and boosters Additionally, the measurements of velocity field around the ERP using the Particle Image Velocimetry (PIV) has been performed. Based on the wind tunnel test, an influence of fins and boosters on aerodynamic characteristics of the rocket has been described. Results of the wind tunnel tests show relatively high contribution of boosters in total aerodynamic drag. Some conclusions concerning performance and stability of the rocket have been presented.

scholarly journals Assessing the Capability of Computational Fluid Dynamics Models in Replicating Wind Tunnel Test Results for the Rose Fitzgerald Kennedy Bridge

CivilEng ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 1065-1090
Author(s):  
Yuxiang Zhang ◽  
Philip Cardiff ◽  
Fergal Cahill ◽  
Jennifer Keenahan
Keyword(s):  
Wind Tunnel ◽  
Bridge Deck ◽  
Wind Tunnel Test ◽  
Verification And Validation ◽  
Bridge Engineering ◽  
Test Results ◽  
Cfd Model ◽  
Cfd Simulations ◽  
Wind Tunnel Tests ◽  
The Rose

Despite its wide acceptance in various industries, CFD is considered a secondary option to wind tunnel tests in bridge engineering due to a lack of confidence. To increase confidence and to advance the quality of simulations in bridge aerodynamic studies, this study performed three-dimensional RANS simulations and DESs to assess the bridge deck aerodynamics of the Rose Fitzgerald Kennedy Bridge and demonstrated detailed procedures of the verification and validation of the applied CFD model. The CFD simulations were developed in OpenFOAM, the results of which are compared to prior wind tunnel test results, where general agreements were achieved though differences were also found and analyzed. The CFD model was also applied to study the effect of fascia beams and handrails on the bridge deck aerodynamics, which were neglected in most research to-date. These secondary structures were found to increase drag coefficients and reduce lift and moment coefficients by up to 32%, 94.3%, and 52.2%, respectively, which emphasized the necessity of including these structures in evaluations of the aerodynamic performance of bridges in service. Details of the verification and validation in this study illustrate that CFD simulations can determine close results compared to wind tunnel tests.

scholarly journals Wind Tunnel Tests of the Tu-154M Aircraft Aerodynamic Characteristics

2019 ◽  
Vol 26 (3) ◽  
pp. 113-120
Author(s):  
Andrzej Krzysiak
Keyword(s):  
Wind Tunnel ◽  
Aerodynamic Characteristics ◽  
Full Scale ◽  
Control Surface ◽  
Rolling Moment ◽  
Wind Tunnel Tests ◽  
Aircraft Model ◽  
University Of Technology ◽  
The Military ◽  
Control Surfaces

Abstract Determination of possible manoeuvres to be performed by the aircraft requires knowledge of its aerodynamic characteristics including, in particular, characteristics of the aircraft at configuration with deflected control surfaces. In this article, the wind tunnel tests results of the model of passenger Tu-154M aircraft manufactured at the scale 1:40 are presented. The model was designed and manufactured by the Military University of Technology based on the Tu-154M aircraft geometry obtained by full-scale object scanning. The model mapped all aircraft control surfaces, along with the gaps between these surfaces and the main wing part. During the tests all the model’s control surface like, flaps, ailerons, spoilers, slots, rudder, elevator and tail plane were deflected at the same deflection angles range as they are used in the full scale aircraft. The aerodynamic characteristics of the tested Tu-154M aircraft model were measured by the 6-component internal balance. Based on the obtained measurements the aircraft model aerodynamic coefficients were calculated. In the article the basic aerodynamic characteristics of the tested Tu-154M aircraft model i.e. lift, drag coefficients as well as pitching, yawing and rolling moment coefficients versus model angles of attack and sideslip angles were presented. The tests were performed in the Institute of Aviation low speed wind tunnels T-1 of the 1.5 m diameter test section at the undisturbed velocity, V∞ = 40 m/s.

Open Rotor Design Strategy: From Wind Tunnel Tests to Full Scale Multi-Disciplinary Design

2015 ◽  
Author(s):  
Jonathan Vlastuin ◽  
Clément Dejeu ◽  
Anthony Louet ◽  
Jérôme Talbotec ◽  
Ingrid Lepot ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Design Methodology ◽  
Wind Tunnel Test ◽  
Design Strategy ◽  
Design Guidelines ◽  
Full Scale ◽  
Wind Tunnel Tests ◽  
Open Rotor ◽  
Definition Of

For several years, Safran has been involved in the design and optimization of contra rotating open rotors. This innovative architecture is known for allowing drastic reduction in fuel burn, but its development is facing complex technological challenges such as acoustics, aerodynamics, and weight penalty due to the mechanical complexity of an Open Rotor. Since 2010, Safran has been developing the experimental test bench HERA (1/5 mock-up scale) to improve the understanding of the complex aerodynamics and acoustics phenomena involved in the counter rotating propellers configuration. Isolated and installed low speed and high speed wind tunnel campaigns, including PIV measurements have been extremely helpful in defining design guidelines for full scale open rotor specification. These tests have been used as CFD feed-back among other purposes. An iterative process involving CFD optimization (in close collaboration with Cenaero) and wind tunnel test campaigns has been developed over the last 4 years and has led to the definition of an innovative design strategy, which has been successfully tested during the process of the full scale counter rotating propellers design for the SAGE2 ground test demonstrator engine. This phase has evidenced the absolute necessity of a multi-disciplinary design method when it comes to full scale and “rig-ready” design. Ensuring high propulsive efficiency and at the same time, minimizing the acoustic level, while maintaining severe mechanical constraints such as weight, inertia and proper dynamic positioning under control, requires a dedicated and integrated “all inclusive” design process. The aim of this paper is to present the design methodology and some of the wind tunnel tests results carried out over the last 4 years, which have led to the definition of a novel multidisciplinary design methodology that involves CFD, FEM and acoustics.

scholarly journals Convergence of transonic wind tunnel test results of the AGARD-B standard model

2020 ◽  
Vol 48 (4) ◽  
pp. 761-769
Author(s):  
Dijana Damljanović ◽  
Đorđe Vuković ◽  
Goran Ocokoljić ◽  
Boško Rašuo
Keyword(s):  
Wind Tunnel ◽  
Wind Tunnel Test ◽  
Aerodynamic Characteristics ◽  
Test Results ◽  
Aerodynamic Coefficients ◽  
Supersonic Wind Tunnel ◽  
Mean Values ◽  
Wide Range ◽  
Production Technologies ◽  
Mach Numbers

AGARD-B is a widely-used configuration of a standard wind tunnel model. Beside its originally intended application for correlation of data from supersonic wind tunnel facilities, it was tested in a wide range of Mach numbers and, more recently, used for assessment of wall interference effects, validation of computational fluid dynamics codes and validation of new model production technologies. The researchers and wind tunnel test engineers would, naturally, like to know the "true" aerodynamic characteristics of this model, for comparison with their own work. Obviously, such data do not exist, but an estimate can be made of the dispersion of test results from various sources and of the probable "mean" values of the aerodynamic coefficients. To this end, comparable transonic test results for the AGARD-B model at Mach numbers 0.77, Mach 1.0 and Mach 1.17 from six wind tunnels were analyzed and average values and dispersions of the aerodynamic coefficients were computed.

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