Factors Influencing the Performance of Porous Wind Shields

Xu, Yigeng; Virk, Muhammad Shakeel; Knight, Jason; Mustafa, Mohamad Y.; Haritos, George

doi:10.4028/www.scientific.net/amm.321-324.799

Cited by 6 publications

(5 citation statements)

References 16 publications

(21 reference statements)

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“…It would also be of interest in the work of using shielding fences to protect the workforce whilst maintaining some ventilation. 26 However, this is beyond the current scope of work, whereby we concentrate on reducing aerodynamic forces with higher wind velocities.…”

Section: Introductionmentioning

confidence: 99%

Fluid-Structure Interaction of a Spring-Mounted Symmetrical Rigid Wing for Drag Reduction of Cars at Higher Wind Velocities

Knight¹,

Fels

Haritos³

et al. 2020

SAE Technical Paper Series

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This paper details an aeroelastic concept for an adaptive and passive wing, which is primarily aimed for use within automotive sector to reduce drag and fuel emissions. The work will also be of interest in the motorsport sector to improve performance and also some applications within aerospace and renewable energy sectors. The wind tunnel testing of a spring mounted symmetrical NACA 0012 wing in freestream is studied over 0° to 40° angles of incidence. General operation of the concept is verified at low angles in the prestall region with that of a theoretical estimation using finite and infinite wings. Three distinct regions are identified, pre-stall, near-stall and post-stall. The transient limitations associated in the near-stall region with variations in spring loading and flow velocities are discovered. It is identified as a periodic self-sustained oscillation with non-dimensional reduced frequencies in a range of 0.14 to 0.22. Furthermore, performance in the post-stall region along with pre-stall is reported and methods for the adjustment of the elastic element for a desired response are introduced. Evaluation is conducted with regard to an automotive application such as a rear wing on a high downforce race car. Typically a 25% increase in wind velocity in the pre-stall region results in a 3°-5° change in angle of incidence corresponding to a 25-40 % reduction of drag coefficient depending on spring stiffness. Reductions of 20° in angle of incidence with similar 25% increase in wind velocity are typically found in the post-stall region. Even larger reductions are found when transitioning through the stall region. This work provides a valuable insight for a novel concept, but we only recommend its use in the pre-stall region to achieve steady results. Use at higher angles is only recommended if transient effects are not important. Limitations to this proof of concept work are highlighted and future development work is suggested to achieve further increases in performance.

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Section: Introductionmentioning

confidence: 99%

Fluid-Structure Interaction of a Spring-Mounted Symmetrical Rigid Wing for Drag Reduction of Cars at Higher Wind Velocities

Knight¹,

Fels

Haritos³

et al. 2020

SAE Technical Paper Series

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“…Other potential applications of this work could include the fluid-structure interaction of hydrofoils to improve performance [33,34], as well as managing forces on sails used in shipping or wind turbines [35,36] in order to prevent damage in harsh conditions. The work could be applied to the protection of a workforce by using fences that moderate flow while maintaining levels of ventilation in harsh conditions [37]. Certain micro air vehicle and unmanned air vehicle applications could also potentially benefit from passive aerodynamic systems [38][39][40].…”

Section: Introductionmentioning

confidence: 99%

Fluid–Structure Interaction of Symmetrical and Cambered Spring-Mounted Wings Using Various Spring Preloads and Pivot Point Locations

et al. 2021

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The fluid–structure interaction of a pivoting rigid wing connected to a spring and subjected to freestream airflow in a wind tunnel is presented. Fluid–structure interactions can, on the one hand, lead to undesirable aerodynamic behaviour or, in extreme cases, to structural failure. On the other hand, improved aerodynamic performance can be achieved if a controlled application within certain limitations is provided. One application is the reduction of drag of road vehicles at higher speeds on a straight, while maintaining downforce at lower speeds during cornering. Conversely, another application concerns increased downforce at higher windspeeds, enhancing vehicle stability. In our wind tunnel experiments, the angle of incidence of the spring-mounted wing is either increased or decreased depending on the pivot point location and spring torque. Starting from a specified initial angle, the aerodynamic forces overcome a pre-set spring preload at incrementally increased freestream velocity. Reynolds numbers at a range of Re = 3 × 104 up to Re = 1.37 × 105 are considered. The application of a symmetrical NACA 0012 and a cambered NACA 6412 airfoil are tested in the wind tunnel and compared. For both airfoils mounted ahead of the aerodynamic centre, stable results were achieved for angles above 15 and below 12 degrees for the symmetrical airfoil, and above 25 and between 10 and −2 degrees for the cambered airfoil. Unsteady motions were observed around the stall region for both airfoils with all spring torque settings and also below −2 degrees for the cambered airfoil. Stable results were also found outside of the stall region when both airfoils were mounted behind the aerodynamic centre, although the velocity ranges were much smaller and highly dependent on the pivot point location. An analysis is reported concerning how changing the spring torque settings at each pivot point location effects performance. The differences in performance between the symmetrical and cambered profiles are then presented. Finally, an evaluation of the systems’ effects was conducted with conclusions, future improvements, and potential applications.

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“…need to be considered in the optimization. All of which will have non-negligible impacts on the performance of a porous A c c e p t e d M a n u s c r i p t fence [4,6,7].…”

Section: Introductionmentioning

confidence: 99%

Feasibility of Computational Fluid Dynamics for Analyzing Airflow Around Porous Fences

Calay

Mustafa

2019

Heat Transfer Engineering

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This paper presents using the computational fluid dynamics (CFD) modelling to analyze the flow around porous fences. The feasibility of applying two-and three-dimensional models was assessed with respect to corresponding wind tunnel experiments. Comparisons between the flow structures on leeward of the fence as predicted by CFD models and the wind tunnel measurements were discussed. Velocity values for the two modelling approaches were in good agreement. However, there is a noticeable discrepancy in predicting the turbulence structure. Both two-and three-dimensional model have demonstrated the capability to predict flow characteristics necessary for the design of porous fences. However, the selection between two-and three-dimensional model is dependent on, design stage and the extent of accuracy required by the application. The A c c e p t e d M a n u s c r i p t Notes on Contributors Yizhong Xu received his PhD degree in Mechanical Engineering from University of Hertfordshire, UK. His research work covers a wide range of the topics related to civil engineering, composite materials, environmental technology and fluid dynamics. He has expertise in wind tunnel experiments and numerical simulations. He has published about 20 peer-reviewed journal papers and international conference proceedings. At present his is a researcher at Department of Building, Energy and Material Technology at UiT/ the Arctic University of Norway, and is a member of the department research group (BEaM). Rajnish K. Calay has a broad engineering background with Bachelors in Civil Engineering, India and masters and PhD in Mechanical Engineering from Cranfield University, UK. She has 30 years of experience in academia and industry in UK and India. At present, she is professor in Energy Systems and research leader at the Department of Building, Energy and Material Technology at the Arctic University of Norway, UiT. Her research has a strong focus on investigating thermofluid problems related to buildings, automotive and aerospace applications and providing solutions for better energy efficiency and developing sustainable energy technologies. She has published about 100 peer-reviewed journal publications and international conference papers. Her research outputs cover essential topics related to sustainable built environment (energy saving, thermal comfort and heat transfer), HVAC flows, renewable energy technologies (such as wind energy, bio energy, fuel cell modelling and design). She is a member of Accreditation panel of and Energy Institute, UK, committee member BSI, UK, Editorial Board Member.

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Factors Influencing the Performance of Porous Wind Shields

Cited by 6 publications

References 16 publications

Fluid-Structure Interaction of a Spring-Mounted Symmetrical Rigid Wing for Drag Reduction of Cars at Higher Wind Velocities

Fluid-Structure Interaction of a Spring-Mounted Symmetrical Rigid Wing for Drag Reduction of Cars at Higher Wind Velocities

Fluid–Structure Interaction of Symmetrical and Cambered Spring-Mounted Wings Using Various Spring Preloads and Pivot Point Locations

Feasibility of Computational Fluid Dynamics for Analyzing Airflow Around Porous Fences

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