Relevant bibliographies by topics / Leading edge tubercles

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  2. Dissertations / Theses
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  4. Book chapters
  5. Conference papers

Academic literature on the topic 'Leading edge tubercles'

Author: Grafiati
Published: 4 June 2021
Last updated: 6 February 2022

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Journal articles on the topic "Leading edge tubercles"

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Weber, Paul W., Laurens E. Howle, and Mark M. Murray. "Lift, Drag, and Cavitation Onset On Rudders With Leading-edge Tubercles." Marine Technology and SNAME News 47, no. 01 (January 1, 2010): 27–36. http://dx.doi.org/10.5957/mtsn.2010.47.1.27.

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This paper presents the experimental measurement of lift and drag as well as the determination of the onset of cavitation on rudders with leading-edge protuberances (tubercles) that are operating at low to moderate Reynolds Numbers in water. The leading-edge shape used for the rudders in this study is derived from our earlier work concerning the analysis of the leading-edge morphology found on the pectoral flippers of humpback whales. While humpback whales do not swim at speeds that induce cavitation, engineered control surfaces based on this bio-inspired control surface modification might operate in cavitation conditions. This point motivates our present work to investigate the onset of cavitation on small aspect ratio rudders with tubercles. Our findings are that (i) the presence of leading-edge tubercles accelerates the onset of cavitation, (ii) the tubercles can modify the location of the onset of cavitation, (iii) the tubercle geometry has an influence on the rudder's hydrodynamic performance, (iv) for the lower Reynolds Numbers considered in this paper, the tubercles decrease lift and increase drag for angles of attack between 15 and 22 deg, (v) for angles above 22 deg, rudders with tubercles generate more lift than smooth rudders, and (vi) for the higher Reynolds Numbers investigated, the difference in performance between the smooth and tubercled rudders diminishes, suggesting the existence of a critical Reynolds Number for a given tubercle geometry beyond which tubercles have no significant effect on hydrodynamic performance.
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Chang, Xin, Xin Ning Wang, and Xiang Ru Cheng. "Research on Hydrodynamic Performance of Three-Dimensional Airfoil with Tubercles on Leading-Edge." Applied Mechanics and Materials 575 (June 2014): 405–13. http://dx.doi.org/10.4028/www.scientific.net/amm.575.405.

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This paper aims to improve and control hydrodynamic performance of three-dimensional airfoils and investigate hydrodynamic performance of three-dimensional airfoil with tubercles on leading-edge by imitating the sinusoidal leading-edge systematically. Based on the DES method, a series of parameters, such as amplitudes and numbers of tubercles, had been studied via the FLUENT software with model constructed by ICEM software and divided by structural grid. According to the results, the amplitudes significantly affect the hydrodynamic performance of three-dimensional airfoil. With maintaining other conditions,tubercle airfoils can make stall angle delay, raise the lift and the drag ratio coefficient. Especially, if there is a bigger attack angle, it is better to reduce resistance and save energy, which will be a cornerstone for further study. It is of vital importance to find out appropriate amplitudes and numbers of tubercles to achieve further progress in hydrodynamic performance of three-dimensional airfoil.
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Baofeng, Tu, Zhang Kai, and Hu Jun. "Investigation on Performance of Compressor Cascade with Tubercle Leading Edge Blade." International Journal of Turbo & Jet-Engines 37, no. 3 (August 27, 2020): 295–303. http://dx.doi.org/10.1515/tjj-2019-0023.

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AbstractIn order to improve compressor performance using a new design method, which originates from the fins on a humpback whale, experimental tests and numerical simulations were undertaken to investigate the influence of the tubercle leading edge on the aerodynamic performance of a linear compressor cascade with a NACA 65–010 airfoil. The results demonstrate that the tubercle leading edge can improve the aerodynamic performance of the cascade in the post-stall region by reducing total pressure loss, with a slight increase in total pressure loss in the pre-stall region. The tubercles on the leading edge of the blades cause the flow to migrate from the peak to the valley on the blade surface around the tubercle leading edge by the butterfly flow. The tubercle leading edge generates the vortices similar to those created by vortex generators, splitting the large-scale separation region into multiple smaller regions.
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Gopinathan, Veerapathiran Thangaraj, John Bruce Ralphin Rose, and Mohanram Surya. "Investigation on the effect of leading edge tubercles of sweptback wing at low reynolds number." Mechanics & Industry 21, no. 6 (2020): 621. http://dx.doi.org/10.1051/meca/2020095.

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Aerodynamic efficiency of an airplane wing can be improved either by increasing its lift generation tendency or by reducing the drag. Recently, Bio-inspired designs have been received greater attention for the geometric modifications of airplane wings. One of the bio-inspired designs contains sinusoidal Humpback Whale (HW) tubercles, i.e., protuberances exist at the wing leading edge (LE). The tubercles have excellent flow control characteristics at low Reynolds numbers. The present work describes about the effect of tubercles on swept back wing performance at various Angle of Attack (AoA). NACA 0015 and NACA 4415 airfoils are used for swept back wing design with sweep angle about 30°. The modified wings (HUMP 0015 A, HUMP 0015 B, HUMP 4415 A, HUMP 4415 B) are designed with two amplitude to wavelength ratios (η) of 0.1 & 0.24 for the performance analysis. It is a novel effort to analyze the tubercle vortices along the span that induce additional flow energy especially, behind the tubercles peak and trough region. Subsequently, Co-efficient of Lift (CL), Co-efficient of Drag (CD) and boundary layer pressure gradients also predicted for modified and baseline (smooth LE) models in the pre & post-stall regimes. It was observed that the tubercles increase the performance of swept back wings by the enhanced CL/CD ratio in the pre-stall AoA region. Interestingly, the flow separation region behind the centerline of tubercles and formation of Laminar Separation Bubbles (LSB) were asymmetric because of the sweep.
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Hansen, Kristy L., Nikan Rostamzadeh, Richard M. Kelso, and Bassam B. Dally. "Evolution of the streamwise vortices generated between leading edge tubercles." Journal of Fluid Mechanics 788 (January 12, 2016): 730–66. http://dx.doi.org/10.1017/jfm.2015.611.

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Sinusoidal modifications to the leading edge of a foil, or tubercles, have been shown to improve aerodynamic performance under certain flow conditions. One of the mechanisms of performance enhancement is believed to be the generation of streamwise vortices, which improve the momentum exchange in the boundary layer. This experimental and numerical study investigates the formation and evolution of these streamwise vortices at a low Reynolds number of $Re=2230$, providing insight into both the averaged and time-dependent flow patterns. Furthermore, the strength of the vortices is quantified through calculation of the vorticity and circulation, and it is found that the circulation increases in the downstream direction. There is strong agreement between the experimental and numerical observations, and this allows close examination of the flow structure. The results demonstrate that the presence of strong pressure gradients near the leading edge gives rise to a significant surface flux of vorticity in this region. As soon as this vorticity is created, it is stretched, tilted and diffused in a highly three-dimensional manner. These processes lead to the generation of a pair of streamwise vortices between the tubercle peaks. A horseshoe-shaped separation zone is shown to initiate behind a tubercle trough, and this region of separation is bounded by a canopy of boundary-layer vorticity. Along the sides of this shear layer canopy, a continued influx of boundary-layer vorticity occurs, resulting in an increase in circulation of the primary streamwise vortices in the downstream direction. Flow visualisation and particle image velocimetry studies support these observations and demonstrate that the flow characteristics vary with time, particularly near the trailing edge and at a higher angle of attack. Numerical evaluation of the lift and drag coefficients reveals that, for this particular flow regime, the performance of a foil with tubercles is slightly better than that of an unmodified foil.
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Pena, Blanca, Ema Muk-Pavic, Giles Thomas, and Patrick Fitzsimmons. "Numerical analysis of a leading edge tubercle hydrofoil in turbulent regime." Journal of Fluid Mechanics 878 (September 6, 2019): 292–305. http://dx.doi.org/10.1017/jfm.2019.611.

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This paper presents a numerical performance evaluation of the leading edge tubercles hydrofoil with particular focus on a fully turbulent flow regime. Efforts were focused on the setting up of an appropriate numerical approach required for an in-depth analysis of this phenomenon, being able to predict the main flow features and the hydrodynamic performance of the foil when operating at high Reynolds numbers. The numerical analysis was conducted using an improved delayed detached eddy simulation for Reynolds numbers corresponding to the transitional and fully turbulent flow regimes at different angles of attack for the pre-stall and post-stall regimes. The results show that tubercles operating in turbulent flow improve the hydrodynamic performance of the foil when compared to a transitional flow regime. Flow separation was identified behind the tubercle troughs, but was significantly reduced when operating in a turbulent regime and for which we have identified the main flow mechanisms. This finding confirms that the tubercle effect identified in a transitional regime is not lost in a turbulent flow. Furthermore, when the hydrofoil operates in the turbulent flow regime, the transition to a turbulent regime takes place further upstream. This phenomenon suppresses a formation of a laminar separation bubble and therefore the hydrofoil exhibits a superior hydrodynamic performance when compared to the same foil in the transitional regime.
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Fish, Frank E., Paul W. Weber, Mark M. Murray, and Laurens E. Howle. "Marine Applications of the Biomimetic Humpback Whale Flipper." Marine Technology Society Journal 45, no. 4 (July 1, 2011): 198–207. http://dx.doi.org/10.4031/mtsj.45.4.1.

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AbstractThe biomimetic approach seeks technological advancement through a transfer of technology from natural technologies to engineered systems. The morphology of the wing-like flipper of the humpback whale has potential for marine applications. As opposed to the straight leading edge of conventional hydrofoils, the humpback whale flipper has a number of sinusoid-like rounded bumps, called tubercles, which are arranged periodically along the leading edge. The presence of the tubercles modifies the water flow over the wing-like surface, creating regions of vortex generation between the tubercles. These vortices interact with the flow over the tubercle and accelerate that flow, helping to maintain a partially attached boundary layer. This hydrodynamic effect can delay stall to higher angles of attack, increases lift, and reduces drag compared to the post-stall condition of conventional wings. As the humpback whale functions in the marine environment in a Reynolds regime similar to some engineered marine systems, the use of tubercles has the potential to enhance the performance of wing-like structures. Specific applications of the tubercles for marine technology include sailboat masts, fans, propellers, turbines, and control surfaces, such as rudders, dive planes, stabilizers, spoilers, and keels.
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Chen, Shuling, Yan Liu, Changzhi Han, Shiqiang Yan, and Zhichao Hong. "Numerical Investigation of Turbine Blades with Leading-Edge Tubercles in Uniform Current." Water 13, no. 16 (August 13, 2021): 2205. http://dx.doi.org/10.3390/w13162205.

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Inspired by the tubercles on humpback whale flippers, leading-edge tubercles have been incorporated into the design of wings and turbine blades in an attempt to improve their hydrodynamic performance. Although promising improvements, especially in terms of the stall performance, have been demonstrated in the limited research that exists to date, the effectiveness of the leading-edge tubercles seems to be influenced by the base blade. This paper focuses on the introduction of sinusoidal leading-edge tubercles to a base blade developed from the classic NACA0018 airfoil, and numerically investigates the effectiveness of leading-edge tubercles on the hydrodynamics associated with the blade in uniform current with different attack angles. Both the macroscopic parameters, such as the lift and drag forces, and the micro-scale flow characteristics, including the vortex and flow separation, are analyzed. The results indicate that the leading-edge tubercles brings a significant influence on the hydrodynamic forces acting on the blade when subjected to an attack angle greater than 15°. This study also reveals the important role of the turbulence and flow separation on hydrodynamic loading on the blade and the considerable influence of the tubercles on such micro-scale flow characteristics. Although the conditions applied in this work are relatively ideal (e.g., the blade is fixed in a uniform flow and the end effect is ignored), the satisfactory agreement between the numerical and corresponding experimental data implies that the results are acceptable. This work builds a good reference for our future work on the hydrodynamic performance of tidal turbines which adopt this kind of blade for operating in both uniform and shearing currents.
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Zhang, Li Hong, Wei Jie Li, and Ji Xin Yin. "Numerical Simulation of Bionic Wing for Drag Reduction." Advanced Materials Research 602-604 (December 2012): 1761–64. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.1761.

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According to the presence of the rounded protuberances or tubercles located on the leading edge, a similar leading edge of humpback whale pectoral fin with the “paraganglioma” has been made on the leading edge of NACA63-210 wing, an bionic NACA63-210 airfoil is designed with convex-concaved leading edges, and the 3-dimensional flows around the bionic wing are simulated for the drag reduction purpose.
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Xingwei, Zhang, Zhou Chaoying, Zhang Tao, and Ji Wenying. "Numerical study on effect of leading‐edge tubercles." Aircraft Engineering and Aerospace Technology 85, no. 4 (June 28, 2013): 247–57. http://dx.doi.org/10.1108/aeat-feb-2012-0027.

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Dissertations / Theses on the topic "Leading edge tubercles"

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Stanway, Michael Jordan. "Hydrodynamic effects of leading-edge tubercles on control surfaces and in flapping foil propulsion." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/42917.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2008.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 99-101).
This thesis investigates the hydrodynamic effects of biologically-inspired leading-edge tubercles. Two complementary studies examine the performance of three-dimensional hydrofoils based on the pectoral flippers of the Humpback whale (novangilae megaptera). The first study uses a static foil, with application to conventional control surfaces--such as rudders or dive planes--found on marine vehicles. The second study uses a dynamic foil, with application to flapping foil propulsion. The lift and drag characteristics of foils with and without tubercles are compared using force measurements from experiments conducted in a water tunnel at four Reynolds numbers between 4.4 x 104 and 1.2 x 105. Results from these experiments indicate the foils stall from the trailing edge in the range of Reynolds numbers tested. Stall was delayed on the foil with tubercles; maximum lift was reduced in all cases but the highest Re. PIV flow visualization at Re = 8.9 x 104 showed flow separation at the trailing edge of both foils as attack angle was increased, confirming that the foils were in trailing edge stall. Surface normal vorticity in ensemble averaged flow fields showed distinct pairs of opposite sign vortical structures being generated by the tubercles, providing some insight into the fluid dynamic mechanism that leads to changes in the performance of a foil with tubercles. Tubercles were used on a flapping foil for the first time. Mean thrust coefficient, CT , power coefficient, CP , and efficiency, n, were measured over a wide parametric space. The maximum thrust coefficient and efficiency measured using the smooth control foil were CT = 3.511 and n = 0.678. The maxima using the tubercled test foil were CT = 3.366 and n = 0.663. In general, the foil with tubercles performed worse than the control, and this performance deficit grew with increased loading.
(cont.) These results suggest that the vortical structures generated by the tubercles interfere with the thrust wake generated by flapping, ultimately degrading performance.
by Michael Jordan Stanway.
S.M.
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2

Fassmann, Wesley N. "An Experimental Study of Bio-Inspired Force Generation by Unsteady Flow Features." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5316.

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As the understanding of the workings of the biological world expands, biomimetic designs increasingly move into the focus of engineering research studies. For this thesis, two studiesinvolving leading edge vortex generation for lift production as observed in nature were explored intheir respective flow regimes. The first study focused on the steady state analysis of streamwise vortices generated byleading edge tubercles of an adult humpback whale flipper. A realistic scaled model of a humpbackflipper was fabricated based on the 3D reconstruction from a sequence of 18 images taken whilecircumscribing an excised flipper of a beached humpback whale. Two complementary modelswith smooth leading edges were transformed from this original digitized model and fabricatedfor testing to further understand the effect of the leading edge tubercles. Experimentally-obtainedforce and qualitative flow measurements were used to study the influence of the leading edgetubercles. The presence of leading edge tubercles are shown to decrease maximum lift coefficient(Cl ), but increase Cl production in the post-stall region. By evaluating a measure of hydrodynamicefficiency, humpback whale flipper geometry is shown to be more efficient in the pre-stall regionand less efficient in the post-stall region as compared to a comparable model with a smooth leadingedge. With respect to a humpback whale, if the decrease in efficiency during post-stall angles ofattack was only required during short periods of time (turning), then this decrease in efficiencymay not have a significant impact on the lift production and energy needs. For the pursuit ofbiomimetic designs, this decrease in efficiency could have potential significance and should beinvestigated further. Qualitative flow measurements further demonstrate that these force results aredue to a delay of separation resulting from the presence of tubercles.The second study investigated explored the effects of flapping frequency on the passive flowcontrol of a flapping wing with a sinusoidal leading edge profile. At a flapping frequency of f =0.05 Hz, an alternating streamwise vortical formation was observed for the sinusoidal leading edge,while a single pair of vortices were present for the straight leading edge. A sinusoidal leading edgecan be used to minimize spanwise flow by the generation of the observed alternating streamwisevortices. An increase in flapping frequency results in these streamwise vortices becoming stretchedin the path of the wing. The streamwise vortices are shown to minimize spanwise flow even afterbeing stretched. Once instabilities are formed at f ≥ 0:1 Hz due to velocity shearing generatedby the increase in cross-radial velocity, the alternating streamwise vortices begin to break downresulting in a increase of spanwise flow.
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Cho, Byong-Chun Ben. "The effect of biologically-inspired, passive, leading-edge tubercles on static and flapping wing flight." 2007. http://link.library.utoronto.ca/eir/EIRdetail.cfm?Resources__ID=452781&T=F.

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Nemirini, Tshamano. "Improving the performance of horizontal axial wind turbines using Bioinspired." Diss., 2021. http://hdl.handle.net/10500/27838.

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Small-scale wind turbines were not considered viable in the past due to their poor efficiencies, mainly because of their aerodynamic effects around the irfoil shape. Recently researchers have renewed interest in enhancing the aerodynamic performances of the blades’ designs inspired by the aerodynamic pattern of biological characteristics of insects and marine mammals such as locusts, dragonflies, damselflies, Humpback Whales etc. Bioinspired wing designs have advantages compared to conventional smooth irfoil blades as they can counter the bending forces that the wings experience during flapping. Bio-inspired corrugated airfoil based on dragonfly wing geometries have been reported to perform well compared to conventional airfoil at low Reynolds numbers. Corrugated airfoils reduce flow separation and enhance aerodynamic performance by trapping vortices in the corrugations thus drawing flow towards the airfoil’s surface. This results in the higher lift whilst incurring only marginally higher drag. Such airfoils also have an advantage when it comes to span-wise structural stiffness due to the corrugated cross-sections. Replacing conventional turbine blades by tubercles or corrugated blades could enhance turbine performance by reducing the pressure gradient along the leading edge; however, the aerodynamic effects at the leading edge will depend on the variations of wavelength and amplitude. In this study, two types of computational studies were investigated: Optimising a corrugated airfoil and investigating the aerodynamic effects of a sinusoidal shape at the leading edge of a blade. Previous studies used an idealized geometry based on the dragonfly wing cross-section profile but did not attempt to optimize the geometry. In the present study: a two-dimensional CFD model is constructed using ANSYS Fluent Workbench-Design Explorer to determine the optimal corrugated blade profile for four angles of attack (AOA) from 5° to 20° corresponding to typical AOA of small-scale wind turbine blades. Two modified blades with variations of wavelength and amplitude at the leading edge were studied to investigate the aerodynamic effects. Three-dimensional models were constructed using Qblade software and 3D points were exported to AutoCAD Inventor to generate the CAD model. The governing equations used are continuity and Navier-Stokes equations written in a frame reference rotating with the blade. The CFD package used is ANSYS FLUENT 19.0. The simulation was run under steady-state, using SST-k omega turbulence model. The modifications have improved the aerodynamic performance. The optimised corrugated blade produced a maximum increase of CL and L/D. Both modified blades (1 and 2) had their performances measured separately and compared to that of baseline blade SG6042 (Conventional blade). Modified blade 1 had a lower wavelength and amplitude at the leading edge of 14.3 % and 4 % respectively of the chord. It was noted that the aerodynamic performance decreased by 6%. Modified model 2, on the other hand had a higher wavelength and amplitude at the leading edge. of 40.4 % and 11.9 % respectively of the chord. It was also noted the aerodynamic performance increased by 6%. From the empirical evidence highlighted above, it can be observed that there is a direct correlation between wavelength, amplitude, and aerodynamic performance of the blade.
Electrical and Mining Engineering
M. Tech. (Engineering)
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Wang, Shih-Jie, and 王識捷. "Numerical Simulations of Wingtip-Mounted Tractor Propeller and Tubercle Leading Edge Airfoil." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/ca7b76.

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碩士
國立交通大學
機械工程系所
108
In this research, the improvement of the aerodynamic characteristics of a wing by means of reduction of wingtip vortex using wingtip-mounted propeller setup and tubercle leading edge design will be discussed. The effect to the wingtip vortex of tip-mounted propeller on a straight wing, as well as on a tubercle design wing, will be inspected; the overall differences brought by the two designs to lift and drag performance of the airfoil will be assessed as well. The 3-D transient simulation in this research is carried out using ANSYS Fluent, applying RANS equation with Spalart-Allmaras turbulence model and solved by SIMPLE algorithm. Sliding Mesh Method is used for the implementation of the rotation of the propeller. The result shows massive lift/drag improvement of tip-mounted propeller when both environment flow speed and the angle of attack is low, but quickly diminishes as the angle of attack increases; under higher flow speed, the benefits are incremental at any angle of attack. The tubercle designs applied in the research show little effect to the wing-propeller setup.
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Yung-ShiunJuang and 莊詠勛. "An Experimental Study on the Flow Field Structure of Low Aspect Ratio Foils with Leading Edge Tubercle." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/26607103324194069939.

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碩士
國立成功大學
系統及船舶機電工程學系
102
Leading edge tubercle is a kind of flow field control method inspired from the humpback whale flippers. In the past, several researches have proving leading edge tubercle enhances lift and drag force of foil at high attack angle, but the principle of performance still has not been clearly realized, so in this research the difference of flow field structure between NACA0012 foil with leading edge tubercle and origin foil will be compared in order to discuss the influence of tubercle to foil. In this study, we use flow visualization method and flow field velocimetry as research tools. The method of flow visualization is suggested by ship model test. By ink tracing, we can realize several complex phenomenon like vortex, flow field reattachment, and turbulence. We use LDV (Laser Doppler Velocimetry) to measure flow speed. By comparing between foils with leading edge tubercles and the origin foil, it is suggested that vortex close to tubercle trough is the main reason of flow structure change, and the results of foil surface speed measurement clarified that leading edge tubercle delayed the development of flow field.
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LIN, YU-CHEN, and 林諭辰. "Study Of The Effect Of Wing With Bionic Tubercles Design On Leading Edges On The Aerodynamic Performance And Tip-Vortex Structure." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/5h3cnh.

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碩士
國立雲林科技大學
機械工程系
107
The presence of the wing tip vortex not only causes the reduction of the aircraft's lift and the increase of the resistance, but also greatly affects the performance of the aircraft, generates noise, and even threatens the safety of the surrounding aircraft. Therefore, it is a big problem that cannot be ignored. The methods used to destroy the wing tip vortex structure are constantly being introduced. The current methods can be divided into active and passive types, and the main difference is whether or not any auxiliary power is used. This study focuses on the effects of bionic tubercles (passive design) on aerodynamic performance, wing tip vortex, and flow field separation. The object of the study was the NACA0021 three-dimensional wing model with bionic tubercles. Six different amplitude/wavelength ratio nodule designs were considered. During the research, the balance instrument, the pitot static tube, the smoke flow field observation experiment and the experiment were carried out. The measurement and simulation results of the commercial simulation software ANSYS Fluent are used to explore and compare the performance differences. According to the comparison and analysis of the experimental and simulation results, it is found that the addition of tubercles is effective for increasing the lift and reducing the resistance, but the degree of improvement will vary with the wind speed or angle of attack. The smaller the wavelength of the tubercles, the more significant the improvement in performance. If we observe the change of the horizontal velocity distribution in the vertical direction of the wing tail edge, it can be found that after adding the tubercles, the size range of the separation zone can be obviously improved within the angle of attack of 10-20 degrees. As far as the wing tip vortex structure is concerned, the strength of the vortex can be effectively suppressed after the addition of the tubercles, especially when the angle of attack is 15 degrees, the wing tip vortex improvement effect is most obvious.
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Books on the topic "Leading edge tubercles"

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New, Daniel T. H., and Bing Feng Ng, eds. Flow Control Through Bio-inspired Leading-Edge Tubercles. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-23792-9.

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New, Daniel T. H., and Bing Feng Ng. Flow Control Through Bio-inspired Leading-Edge Tubercles: Morphology, Aerodynamics, Hydrodynamics and Applications. Springer, 2020.

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Cho, Byong-Chun Ben. The effect of biologically-inspired, passive, leading-edge tubercles on static and flapping wing flight. 2007.

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Book chapters on the topic "Leading edge tubercles"

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New, T. H., Zhaoyu Wei, Y. D. Cui, I. Ibrahim, and W. H. Ho. "Flow Control by Hydrofoils with Leading-Edge Tubercles." In Flow Control Through Bio-inspired Leading-Edge Tubercles, 85–109. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-23792-9_4.

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Feng, Lihao, and Jinjun Wang. "Leading-Edge Tubercles on Swept and Delta Wing Configurations." In Flow Control Through Bio-inspired Leading-Edge Tubercles, 111–29. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-23792-9_5.

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Hrynuk, John, and Douglas Bohl. "Effects of Leading-Edge Tubercles on Dynamically Pitching Airfoils." In Flow Control Through Bio-inspired Leading-Edge Tubercles, 131–46. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-23792-9_6.

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Rostamzadeh, N., K. Hansen, and R. Kelso. "Tubercled Wing Flow Physics and Performance." In Flow Control Through Bio-inspired Leading-Edge Tubercles, 41–68. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-23792-9_2.

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Kelso, R., N. Rostamzadeh, and K. Hansen. "Tubercle Geometric Configurations: Optimization and Alternatives." In Flow Control Through Bio-inspired Leading-Edge Tubercles, 69–84. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-23792-9_3.

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Ng, Bing Feng, Edwin Jit Guan Ong, Rafael Palacios, and T. H. New. "Effects of Leading-Edge Tubercles on Structural Dynamics and Aeroelasticity." In Flow Control Through Bio-inspired Leading-Edge Tubercles, 147–73. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-23792-9_7.

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Fish, Frank E. "Biomimetics and the Application of the Leading-Edge Tubercles of the Humpback Whale Flipper." In Flow Control Through Bio-inspired Leading-Edge Tubercles, 1–39. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-23792-9_1.

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Mishra, Alok, Saravana Kumar Lakshmanan, and Ashoke De. "Effect of Leading-Edge Tubercle on Aerodynamic Performance of NACA 0021 Airfoil." In Lecture Notes in Mechanical Engineering, 163–70. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-5849-3_17.

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Lositaño, Ian Carlo M., and Louis Angelo M. Danao. "Modelling the Performance of a Vertical Axis Wind Turbine with Cambered Tubercle Leading Edge Blades." In Transactions on Engineering Technologies, 73–86. Singapore: Springer Singapore, 2019. http://dx.doi.org/10.1007/978-981-32-9531-5_6.

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Prakash, Punit, Abhishek Nair, Joseph Manoj, Thomas Mathachan Thoppil, and Nishant Mishra. "Parametric Study of Leading-Edge Tubercle: Bio-inspired Design of Darrieus Vertical Axis Wind Turbine." In Innovations in Sustainable Energy and Technology, 243–51. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-1119-3_22.

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Conference papers on the topic "Leading edge tubercles"

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Sidhu, Satpreet S., Asad Asghar, and William D. E. Allan. "Performance Evaluation of Leading Edge Tubercles Applied to the Blades in a 2-D Compressor Cascade." In ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/gt2021-58798.

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Abstract In the present paper, the performance of compressor blades modified with leading edge tubercles was evaluated and compared with that of a baseline profile at a high subsonic Mach number in a 2-D cascade. Specific tubercle geometries were selected based on an extensive literature survey and a Self-Organizing Map analysis. The compressor blade geometry of a popular aero-engine was reverse-engineered using laser-scanning. Baseline and tubercled compressor blades were 3-D printed and tested. Two sinusoidal tubercle shapes based on different amplitudes and wavelengths and one with a power law profile were selected. A 2-D compressor cascade was designed and commissioned to test these blades at high subsonic Mach number in the transonic wind tunnel at Royal Military College of Canada. Surface flow visualizations were performed with oil for observing and locating compressor blade stall for different sets of blades. Flow direction and the total pressure at the cascade exit were measured using a 5-hole, fast-response, traversing probe. Compressor blade performance was measured and compared with various tubercled blades at various angles of incidence, while maintaining periodicity at the inlet and exit planes. Total pressure loss coefficients were calculated for all 4 blades and compared for 6 positive angle of incidence. Power series tubercled profile resulted in slight improvements in the loss coefficient at 0° incidence and none of tubercled geometry compromized performance at the design point. The baseline blade stalled at 8° and tubercles were capable of delaying stall at this condition. Power series profile outperformed the baseline at all angle of incidence (AOI) with significant improvements at 8° AOI. Power series tubercled profiles performed better than other tubercled geometries at almost all AOI except 10° where sinusoidal tubercled profiles performed better. The presence of smaller valley and broader peaks is attributed with the performance improvement, supported by the flow visualization results.
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Zheng, Tan, Mingmin Zhu, Xiaoqing Qiang, Jinfang Teng, and Jinzhang Feng. "Influence of Leading Edge Tubercles in an Annular Compressor Cascade With Different Hub-Tip Ratios and Aspect Ratios." In ASME Turbo Expo 2017: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/gt2017-64054.

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Humpback whale flippers’ scalloped tubercles on the leading edge are thought to enhance the whale’s underwater maneuverability. Inspired by the flippers, leading edge tubercles are applied in a low speed annular compressor cascade as a type of passive flow control techniques in this paper. A numerical study is performed to investigate the influence of tubercles on the aerodynamic losses and corner separation in the low speed cascades. Different low speed cascades based on a CDA airfoil profile are built with several hub-tip ratios and aspect ratios. Steady RANS simulations are carried out for these cascades with and without leading edge tubercles. The aerodynamic performance and corner separation features are subsequently investigated in these cascades. The influence of tubercles under the variation of hub-tip ratio and aspect ratio is understood and concluded from the comparison of the performance attained by different cascades. Flow visualizations at a post-stall incidence angle show that the interaction between the tubercle-induced streamwise vortices and corner separation vortices plays a crucial role in attenuating the corner separation and reducing losses. By combining the performance analysis and flow visualizations, this paper discusses the mechanism of leading edge tubercles in a low speed annular compressor cascade with different hub-tip ratios and aspect ratios.
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Colpitts, Robert R., Ruben E. Perez, and Peter W. Jansen. "Effect of Leading-Edge Tubercles on Rotor Blades." In AIAA AVIATION 2020 FORUM. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2020. http://dx.doi.org/10.2514/6.2020-2763.

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Du, Longhuan, Robert G. Dominy, and Grant Ingram. "Experimental Investigation of the Performance of H-Darrieus Wind Turbines With Tubercle Leading Edge Blades." In ASME Turbo Expo 2020: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/gt2020-14156.

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Abstract The most significant challenge associated with employing small-scale H-Darrieus wind turbines is to ensure that they self-start without compromising their efficiency at the design operating condition. One of the key and straightforward methods to improve the turbine performance is to choose an optimized blade profile. It has been shown that by creating rounded protuberances (tubercles) around the blade leading edge, not only do the blades demonstrate a more gradual stall characteristic but also that the tubercles significantly increase the blade lift performance in the post-stall regime at the expense of slightly degraded lift performance in the pre-stall regime. This effect might be beneficial for the H-Darrieus turbine application where the blades experience extreme incidence range during the turbine start-up period. Therefore, in this study the performance of standard NACA0021 blades is compared experimentally to a modified set of blades which have a sinusoidal tubercle configuration along the original NACA0021 blade leading edge (0 ≤ x ≤ 0.3c). Time-accurate, self-starting data were recorded from wind tunnel tests under different flow conditions and the power coefficient (Cp) versus tip speed ratio (λ) curve was calculated. It is demonstrated conclusively that blades with an appropriate configuration of tubercle leading edges can considerably improve turbine self-starting capability. To the best of the authors’ knowledge, this study provides the first experimental data of H-Darrieus wind turbine performance with tubercle leading edge blades and the data are valuable for future designs and for the validation of simulation models.
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Marino, Alessandro, Mehmet Atlar, and Yigit K. Demirel. "An Investigation of the Effect of Biomimetic Tubercles on a Flat Plate." In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-96276.

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Abstract This paper describes the investigation, by means of Computational Fluid Dynamics (CFD), of the effect of biomimetic tubercles on the hydrodynamics of a fully submerged flat plate. The application of these tubercles takes inspiration from the features of the humpback whale (Megaptera Novaeangliae). These huge marine mammals are capable of quick and agile movements in the water, despite their bulky bodies. Researchers investigated the causes of this ability by studying some peculiar somatic characteristics of these animals, in particular the tubercles on the leading edge of their pectoral fins. These tubercles were applied in the form of sinusoidal perturbations of the leading edge of wing profiles and foils, and they proved to cause a positive effect on the overall performance. The aim of this paper is to investigate another type of tubercles, which appear in the shape of bumps on the whales head. The effect of these tubercles has not been studied yet, and this paper presents a study on the fundamental phenomena they generate in the water flowing on the surface of a flat plate. The tubercles are modelled as axisymmetric sinusoidal bumps placed on the flat plate. Different combinations of these tubercles are studied, in order to assess what the effect of a single tubercle is, and how more tubercles interact when they are placed closed to each other, in different configurations (number of tubercles and relative position). In addition, a systematic study of the effect of a single row of tubercles spanning perpendicularly to the flow is carried out. The tubercles change systematically in amplitude and position along the plate. One further objective of this paper is to investigate if an optimised application of the biomimetic tubercles can lead to a drag reduction for the flat plate. Preliminary simulations show that the rows of tubercles interact with the boundary layer by modifying the pressure distribution, velocity and direction of the flow. The tubercles appear to generate vortices that are similar to those created by sinusoidal tubercles on the leading edge of foils, which tend to thin the boundary layer. A change in the total drag of the plate with tubercle is also noticeable, which even decreases from the baseline (flat plate with no tubercles), at certain combinations of position and tubercle amplitude.
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Bouchard, D., A. Asghar, J. Hardes, R. Edwards, W. D. E. Allan, and M. LaViolette. "Influence of a Novel Three-Dimensional Leading Edge Geometry on the Aerodynamic Performance of Transonic Cascade Vanes." In ASME Turbo Expo 2012: Turbine Technical Conference and Exposition. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/gt2012-69926.

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This paper addresses the issue of aerodynamic performance of a novel 3D leading edge modification to a reference vane. An analysis of tubercles found in nature and some engineering applications was used to synthesize new leading edge geometry. Three variations of the reference low pressure turbine vane were obtained by changing the characteristic parameters of the tubercles. Shock structure, surface flow visualization and total pressure measurements were made through experiments in a cascade rig, as well as through computational fluid dynamics. The tests were carried out at design zero incidence and off-design ±10-deg and ±5-deg incidences. The performance of the new 3D leading edge geometries was compared against the reference vane. Some leading edge tubercle configurations were effective at decreasing total pressure losses at positive inlet incidence angles. Numerical results supplemented experimental results.
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Asghar, Asad, Ruben E. Perez, and William Allan. "Application of Leading Edge Tubercles to Enhance Propeller Performance." In 2018 Applied Aerodynamics Conference. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2018. http://dx.doi.org/10.2514/6.2018-3647.

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Abbasi, Afaq A., Huaxing Li, Xuanshi Meng, Shiqing Yin, and Yuqi Qin. "Effect of Plasma Leading Edge Tubercles on Wing Performance." In 2018 AIAA Aerospace Sciences Meeting. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2018. http://dx.doi.org/10.2514/6.2018-0679.

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Adson Agrico de Paula, Julio Romano Meneghini, Bruno Ricardo Massucatto Padilha, Bento Silva de Mattos, and Roberto Gil Annes da Silva. "Performance of leading edge tubercles for a thin airfoil." In 23rd ABCM International Congress of Mechanical Engineering. Rio de Janeiro, Brazil: ABCM Brazilian Society of Mechanical Sciences and Engineering, 2015. http://dx.doi.org/10.20906/cps/cob-2015-1699.

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Shi, Weichao, Mehmet Atlar, Kwangcheol Seo, Rosemary Norman, and Roslynna Rosli. "Numerical Simulation of a Tidal Turbine Based Hydrofoil With Leading-Edge Tubercles." In ASME 2016 35th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/omae2016-54796.

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The tubercles along the leading edges of the humpback whale flippers can provide these large mammals with an exceptional maneuverability. This is due to the fact that the leading-edge tubercles have largely a 3D benefit for the finite hydrofoils, which can maintain the lift, reduce the drag and delay the stall angle. Newcastle University launched a series study to improve a tidal turbine’s performance with the aid of this concept. This paper presents a numerical simulation of the tested hydrofoil, which is representative of a tidal turbine blade, to investigate the flow around the foil and also to numerically model the experiment. This hydrofoil was designed based on an existing tidal turbine blade with the same chord length distribution but a constant pitch angle. The model tests have been conducted in the Emerson Cavitation Tunnel measuring the lift and drag. The results showed that the leading-edge tubercles can significantly improve the performance of the hydrofoil by improving the lift-to-drag ratio and delaying the stall. By applying Shear Stress Transport (SST), Detached Eddy Simulation (DES) and Large Eddy Simulation (LES) via using the commercial CFD solver, Star-CCM+, the tested hydrofoil models were simulated and more detailed flow information has been achieved to complement the experiment. The numerical results show that the DES model is in close agreement with the experimental results. The flow separation pattern indicates the leading-edge tubercles can energize the flow around the hydrofoil to keep the flow more attached and also separate the flow into different channels through the tubercles.
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