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 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.

scholarly journals Wind tunnel test analysis to determine pantograph noise contribution on a high-speed train

2019 ◽  
Vol 11 (10) ◽  
pp. 168781401988477
Author(s):  
Hee-Min Noh
Keyword(s):  
Wind Tunnel ◽  
Noise Reduction ◽  
High Speed ◽  
Acoustic Noise ◽  
Microphone Array ◽  
Wind Tunnel Test ◽  
Full Scale ◽  
Scale Model ◽  
Test Analysis ◽  
Noise Contribution

In this study, we investigated the characteristics and the influence of the aero-acoustic noise generated from a pantograph using various experimental approaches in a wind tunnel. First, the noise generated at various flow velocities was measured and analyzed using a full-scale pantograph model. Then, the noise generated from the main position of the pantograph was derived using a microphone array attached to one side of a wind tunnel. The noise contributions of the main components of the pantograph were derived from the noise measurements obtained from a step-by-step disassembly of the full-scale model. In addition, the noise reduction achieved by panhead collectors, which are some of the most important noise sources on a pantograph, was examined by studying the results obtained when varying their geometry. In order to analyze the noise-reduction effect achieved by varying the height of the collector, different types of collectors were fabricated and wind tunnel tests were conducted. Through this study, we have investigated the aero-acoustic noise contribution of the major components of a pantograph, and we have developed effective noise-reduction measures for the panhead collector.

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.

Aerodynamic Coefficients of a High-Speed Train in Presence of Windbreaks With Different Gap Configurations

2020 ◽  
Author(s):  
Elia Brambilla ◽  
Gisella Tomasini ◽  
Stefano Giappino
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Full Scale ◽  
High Speed Train ◽  
European Standard ◽  
Aerodynamic Coefficients ◽  
Scaled Model ◽  
Wind Tunnel Tests ◽  
Cfd Analyses ◽  
High Band

Abstract In the present paper the force aerodynamic coefficients measured, according the European Standard Specifications, by means of wind tunnel tests carried out on a 1:15 scaled model of ETR1000 train in presence of different windbreaks configurations, are presented. In particular, 3m high band barriers (40% of porosity) have been tested with different gaps (from 0,5m to 30m, full scale) in the windbreaks and considering different positions of the train with respect to the gaps. The results shown in this paper allow to evaluate the effect of different windbreak parameters (gap amplitude, train position) on the train overturning risk and they represent a complete database for validation of CFD analyses.

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.

Sailing Yacht Rig Improvements Through Viscous Computational Fluid Dynamics

2005 ◽  
Author(s):  
Vincent G. Chapin ◽  
Romaric Neyhousser ◽  
Stephane Jamme ◽  
Guillaume Dulliand ◽  
Patrick Chassaing
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
High Speed ◽  
Stokes Equations ◽  
Wind Tunnel Test ◽  
Physical Modelling ◽  
Optimized Design ◽  
Linear Interaction ◽  
Sailing Yacht

In this paper we propose a rational viscous Computational Fluid Dynamics (CFD) methodology applied to sailing yacht rig aerodynamic design and analysis. After an outlook of present challenges in high speed sailing, we emphasized the necessity of innovation and CFD to conceive, validate and optimize new aero-hydrodynamic concepts. Then, we present our CFD methodology through CAD, mesh generation, numerical and physical modelling choices, and their validation on typical rig configurations through wind-tunnel test comparisons. The methodology defined, we illustrate the relevance and wide potential of advanced numerical tools to investigate sailing yacht rig design questions like the relation between sail camber, propulsive force and aerodynamic finesse, and like the mast-mainsail non linear interaction. Through these examples, it is shown how sailing yacht rig improvements may be drawn by using viscous CFD based on Reynolds Averaged Navier-Stokes equations (RANS). Then the extensive use of viscous CFD, rather than wind-tunnel tests on scale models, for the evaluation or ranking of improved designs with increased time savings. Viscous CFD methodology is used on a preliminary study of the complex and largely unknown Yves Parlier Hydraplaneur double rig. We show how it is possible to increase our understanding of his flow physics with strong sail interactions, and we hope this methodology will open new roads toward optimized design. Throughout the paper, the necessary comparison between CFD and wind-tunnel test will be presented to focus on limitations and drawbacks of viscous CFD tools, and to address future improvements.

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