scholarly journals Aerodynamic investigations of a Vertical Landing Launcher configuration by means of Computational Fluid Dynamics and Wind Tunnel Tests

2022 ◽  
Author(s):  
Jan B. Vos ◽  
Dominique Charbonnier ◽  
Ansgar Marwege ◽  
Ali Guelhan ◽  
Mariasole Laureti ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Wind Tunnel Tests ◽  
Vertical Landing

scholarly journals Wind-Induced Phenomena in Long-Span Cable-Supported Bridges: A Comparative Review of Wind Tunnel Tests and Computational Fluid Dynamics Modelling

2021 ◽  
Vol 11 (4) ◽  
pp. 1642
Author(s):  
Yuxiang Zhang ◽  
Philip Cardiff ◽  
Jennifer Keenahan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Careful Analysis ◽  
Wind Effects ◽  
Wind Tunnel Tests ◽  
Long Span Bridges ◽  
Long Span ◽  
Comparative Review ◽  
Dynamics Modelling

Engineers, architects, planners and designers must carefully consider the effects of wind in their work. Due to their slender and flexible nature, long-span bridges can often experience vibrations due to the wind, and so the careful analysis of wind effects is paramount. Traditionally, wind tunnel tests have been the preferred method of conducting bridge wind analysis. In recent times, owing to improved computational power, computational fluid dynamics simulations are coming to the fore as viable means of analysing wind effects on bridges. The focus of this paper is on long-span cable-supported bridges. Wind issues in long-span cable-supported bridges can include flutter, vortex-induced vibrations and rain–wind-induced vibrations. This paper presents a state-of-the-art review of research on the use of wind tunnel tests and computational fluid dynamics modelling of these wind issues on long-span bridges.

On the aerodynamic characteristics of stay cables attached with helical wires

2017 ◽  
Vol 21 (9) ◽  
pp. 1262-1272 ◽  
Author(s):  
Shouying Li ◽  
Yangchen Deng ◽  
Wei Zhong ◽  
Zhengqing Chen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Vortex Shedding ◽  
Aerodynamic Characteristics ◽  
Wind Tunnel Tests ◽  
Stay Cables ◽  
Computational Fluid Dynamics Simulations ◽  
The Mean ◽  
Dynamics Simulations

To investigate the aerodynamic characteristics of stay cables attached with helical wires, a series of wind tunnel tests and computational fluid dynamics simulations were both carried out on the smooth and helical-wire cable models. The diameters of helical wires include 2, 3, and 4 mm, and the distances between adjacent helical wires include 200, 300, and 600 mm. Pressure taps were uniformly arranged on seven cross sections of the cable models. First, wind tunnel tests including 50 test cases were conducted to measure the wind forces and wind pressures on the cables using the forced vibration system in HD-2 wind tunnel. The effects of the helical wires on the mean and fluctuating aerodynamic forces and the correlation coefficients along the cable axis were investigated in detail based on the experimental data. Second, large Eddy simulation module incorporated in software FLUENT® was used to simulate the aerodynamic forces on the smooth and helical-wire cables. The parameters of the cable and the helical wire are similar to those used in the wind tunnel tests. The results show that helical wires can attenuate vortex shedding and reduce the wind pressure correlation along the cable axis. Within the Reynolds number range from 0.4 × 105 to 1.6 × 105, the mean drag force of the helical-wire cable is lower than the value of the smooth cable, and the correlation coefficient decreases with the increase in wind velocity. The results obtained from wind tunnel tests and computational fluid dynamics simulations agree well with each other. Furthermore, the wind velocity contour around the helical-wire cables obtained from computational fluid dynamics simulations visually indicates that the approaching flow is forced to separate at the surface of the helical wire in advance, which makes the vortex shedding disorder along the cable axis.

Optimization of the three-segment aerofoil arrangement based on wind tunnel tests and numerical analysis

2020 ◽  
pp. 095441002092602
Author(s):  
Wojciech Grendysa ◽  
Bartosz Olszański
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Response Surface ◽  
Lift Coefficient ◽  
Light Transport ◽  
Optimization Approach ◽  
Wind Tunnel Tests ◽  
Transport Aircraft ◽  
Aerodynamic Configuration

This paper presents the optimization of multi-element aerofoil for the LAR-3 Puffin -- STOL light transport aircraft concept proposal. Based on the geometry and aerodynamic characteristics of the well-known and proven in flight three-segment NACA 63A416 aerofoil, the authors explore the possibility of enhancing its high-lift performance by the movement of slot and flap position in extended (deployed) aerodynamic configuration. In order to determine the optimum positions of aerofoil segments (elements), a multi-step optimization approach was developed. It combines computational fluid dynamics simulations that were used for design space screening and preliminary optimization together with low-turbulence wind tunnel tests which yielded certain results. To decrease the numerical cost of the computer simulation campaign, Design of experiment methods (optimal space-filling design among others) were employed instead of exhausting full factorial (parametric) design. Response surface models of major aerodynamic coefficients (lift, drag, pitching moment) at predicted maximum lift coefficient ( C L max) point allowed to narrow down search space and identify several candidates for optimal configuration to be checked experimentally. Wind tunnel tests campaign confirmed the major trends observed in computational fluid dynamics derived response surface contour plots. For the optimum aerodynamic configuration, chosen experimental C L max is over 3.9, which is a 10% increase over the baseline (initial slat and flap positions) case. In parallel, the maximum lift-to-drag ratio gain at that point was almost 19%. The research outlined in this paper was conducted on behalf of the aircraft production company and its results will be applied in a newly designed transport aircraft.

scholarly journals Impact of wheel rotation on the aerodynamic drag of a time trial cyclist

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
Fabio Malizia ◽  
T. van Druenen ◽  
B. Blocken
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Aerodynamic Drag ◽  
Front Wheel ◽  
Wind Tunnel Tests ◽  
Wheel Rotation ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations ◽  
Drag Area

AbstractAerodynamic drag is the main resistive force in cycling at high speeds and on flat terrain. In wind tunnel tests or computational fluid dynamics simulations, the aerodynamic drag of cycling wheels is often investigated isolated from the rest of the bicycle, and sometimes in static rather than rotating conditions. It is not yet clear how these testing and simulating conditions influence the wheel aerodynamic performance and how the inclusion of wheel rotation influences the overall measured or computed cyclist drag. This study presents computational fluid dynamics simulations, validated with wind tunnel tests, that indicate that an isolated static spoked front wheel has a 2.2% larger drag area than the same wheel when rotating, and that a non-isolated static spoked front wheel has a 7.1% larger drag area than its rotating counterpart. However, rotating wheels are also subjected to the rotational moment, which increases the total power required to rotate and translate the wheel compared to static conditions where only translation is considered. The interaction with the bicycle frame and forks lowers the drag area of the front wheel by 8.8% for static and by 12.9% for the rotating condition, compared to the drag area of the isolated wheels. A different flow behavior is also found for static versus rotating wheels: large low-pressure regions develop from the hub for rotating wheels, together with a lower streamwise velocity region inside the circumference of the wheel compared to static wheels. The results are intended to help in the selection of testing/simulating methodologies for cycling spoked wheels.

Vortex-induced vibration of a truss girder with high vertical stabilizers

2018 ◽  
Vol 22 (4) ◽  
pp. 948-959 ◽  
Author(s):  
Haojun Tang ◽  
KM Shum ◽  
Qiyu Tao ◽  
Jinsong Jiang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Vortex Shedding ◽  
Windward Side ◽  
Induced Response ◽  
Vortex Induced Vibration ◽  
Wind Tunnel Tests ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

To improve the flutter stability of a long-span suspension bridge with steel truss stiffening girder, two vertical stabilizers of which the total height reaches to approximately 2.9 m were planned to install on the deck. As the optimized girder presents the characteristics of a bluff body more, its vortex-induced vibration needs to be studied in detail. In this article, computational fluid dynamics simulations and wind tunnel tests are carried out. The vortex-shedding performance of the optimized girder is analyzed and the corresponding aerodynamic mechanism is discussed. Then, the static aerodynamic coefficients and the dynamic vortex-induced response of the bridge are tested by sectional models. The results show that the vertical stabilizers could make the incoming flow separate and induce strong vortex-shedding behind them, but this effect is weakened by the chord member on the windward side of the lower stabilizer. As the vortex-shedding performance of the optimized girder is mainly affected by truss members whose position relationships change along the bridge span, the vortex shed from the girder can hardly have a uniform frequency so the possibility of vortex-induced vibration of the bridge is low. The data obtained by wind tunnel tests verify the results by computational fluid dynamics simulations.

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.

Development of Boundary Layer in CRIACIV in Florence (Prato) and Comparison with CFD

2016 ◽  
Vol 820 ◽  
pp. 359-364
Author(s):  
Marek Magát ◽  
Ivana Olekšáková ◽  
Juraj Žilinský
Keyword(s):  
Fluid Dynamics ◽  
Boundary Layer ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Atmospheric Boundary Layer ◽  
Comparison Of The Results

In this article are described the results from testing profile of atmospheric boundary layer in BLWT (Boundary layer wind tunnel) in Florence (Prato), Italy with emphasis on comparison of the results with simulations in CFD (Computational fluid dynamics) software OpenFoam. The values are compared with calculated values from EuroCode.

scholarly journals Performance prediction of loop-type wind turbine

2020 ◽  
Vol 12 (2) ◽  
pp. 168781401984047
Author(s):  
Wonyoung Jeon ◽  
Jeanho Park ◽  
Seungro Lee ◽  
Youngguan Jung ◽  
Yeesock Kim ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Experimental Results ◽  
Scale Model ◽  
Dynamics Analysis ◽  
Blockage Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Computational Fluid Dynamics Analysis

An experimental and analytical method to evaluate the performance of a loop-type wind turbine generator is presented. The loop-type wind turbine is a horizontal axis wind turbine with a different shaped blade. A computational fluid dynamics analysis and experimental studies were conducted in this study to validate the performance of the computational fluid dynamics method, when compared with the experimental results obtained for a 1/15 scale model of a 3 kW wind turbine. Furthermore, the performance of a full sized wind turbine is predicted. The computational fluid dynamics analysis revealed a sufficiently large magnitude of external flow field, indicating that no factor influences the flow other than the turbine. However, the experimental results indicated that the wall surface of the wind tunnel significantly affects the flow, due to the limited cross-sectional size of the wind tunnel used in the tunnel test. The turbine power is overestimated when the blockage ratio is high; thus, the results must be corrected by defining the appropriate blockage factor (the factor that corrects the blockage ratio). The turbine performance was corrected using the Bahaj method. The simulation results showed good agreement with the experimental results. The performance of an actual 3 kW wind turbine was also predicted by computational fluid dynamics.

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