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Andreas, Edgar L., i Larry Mahrt. "On the Prospects for Observing Spray-Mediated Air–Sea Transfer in Wind–Water Tunnels". Journal of the Atmospheric Sciences 73, nr 1 (21.12.2015): 185–98. http://dx.doi.org/10.1175/jas-d-15-0083.1.
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Abstract Nature is wild, unconstrained, and often dangerous. In particular, studying air–sea interaction in winds typical of tropical cyclones can place researchers, their instruments, and even their research platforms in jeopardy. As an alternative, laboratory wind–water tunnels can probe 10-m equivalent winds of hurricane strength under conditions that are well constrained and place no personnel or equipment at risk. Wind–water tunnels, however, cannot simulate all aspects of air–sea interaction in high winds. The authors use here the comprehensive data from the Air–Sea Interaction Salt Water Tank (ASIST) wind–water tunnel at the University of Miami that Jeong, Haus, and Donelan published in this journal to demonstrate how spray-mediated processes are different over the open ocean and in wind tunnels. A key result is that, at all high-wind speeds, the ASIST tunnel was able to quantify the so-called interfacial air–sea enthalpy flux—the flux controlled by molecular processes right at the air–water interface. This flux cannot be measured in high winds over the open ocean because the ubiquitous spray-mediated enthalpy transfer confounds the measurements. The resulting parameterization for this interfacial flux has implications for modeling air–sea heat fluxes from moderate winds to winds of hurricane strength.
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Tabatabaei, Narges, Ramis Örlü, Ricardo Vinuesa i Philipp Schlatter. "Aerodynamic Free-Flight Conditions in Wind Tunnel Modelling through Reduced-Order Wall Inserts". Fluids 6, nr 8 (27.07.2021): 265. http://dx.doi.org/10.3390/fluids6080265.
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Parallel sidewalls are the standard bounding walls in wind tunnels when making a wind tunnel model for free-flight condition. The consequence of confinement in wind tunnel tests, known as wall-interference, is one of the main sources of uncertainty in experimental aerodynamics, limiting the realizability of free-flight conditions. Although this has been an issue when designing transonic wind tunnels and/or in cases with large blockage ratios, even subsonic wind tunnels at low-blockage-ratios might require wall corrections if a good representation of free-flight conditions is intended. In order to avoid the cumbersome streamlining methods especially for subsonic wind tunnels, a sensitivity analysis is conducted in order to investigate the effect of inclined sidewalls as a reduced-order wall insert in the airfoil plane. This problem is investigated via Reynolds-averaged Navier–Stokes (RANS) simulations, and a NACA4412 wing at the angles of attack between 0 and 11 degrees at a moderate Reynolds number (400 k) is considered. The simulations are validated with well-resolved large-eddy simulation (LES) results and experimental wind tunnel data. Firstly, the wall-interference contribution in aerodynamic forces, as well as the local pressure coefficients, are assessed. Furthermore, the isolated effect of confinement is analyzed independent of the boundary-layer growth. Secondly, wall-alignment is modified as a calibration parameter in order to reduce wall-interference based on the aforementioned assessment. In the outlined method, we propose the use of linear inserts to account for the effect of wind tunnel walls, which are experimentally simple to realize. The use of these inserts in subsonic wind tunnels with moderate blockage ratio leads to very good agreement between free-flight and wind tunnel data, while this approach benefits from simple manufacturing and experimental realization.
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Liu, Jie, Yimeng Wu, Zhanyou Sa, Bingke Wang, Haijun Wang, Hao Wang i Shouqing Lu. "Study on the influence of cross-section shape on the characteristics of wind flow field in heavy-daty railway tunnel". E3S Web of Conferences 536 (2024): 01024. http://dx.doi.org/10.1051/e3sconf/202453601024.
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In order to reduce the coal dust pollution when the heavy train enters the tunnel and to ensure the safety of railroad operation, this paper adopts numerical simulation to study the characteristics of the wind flow field of the heavy train passing through different shapes of tunnels. The results show that the shape of the tunnel section has a significant effect on the piston wind characteristics of the train entering the tunnel. When the train passes through the tunnel, the value of the wind pressure and the gradient of the pressure on the surface of the carriages increase from horseshoe shape, high wall shape and high arch shape. The vortex structure generated at the entrance of the horseshoe tunnel is the smallest and the flow field is more stable, and the wind turbulence shows significant weakening effect; when the rear end of the car enters the tunnel, the range of the influence of the piston winds outside the tunnel is in order of smallest to largest for the horseshoe, high wall, and high arch tunnels; in the wake region, the central region of the strong vorticity zone in the horseshoe tunnel is more continuous, reducing the instability of the airflow in the tunnel. The results of this study are of great significance in understanding the characteristics of the wind flow field and the effect on dust generation when heavy trains pass through the tunnel.
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Yao, Yahu. "Numerical Simulation Analysis of the Influence of Entrance Wind Speed on the Wind Speed Distribution of Coal Mine Tunnel Sections". Academic Journal of Science and Technology 7, nr 3 (29.10.2023): 208–12. http://dx.doi.org/10.54097/ajst.v7i3.13399.
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In order to further accurately obtain the wind speed of coal mine tunnels and achieve intelligent ventilation, taking the Wuhushan coal mine tunnel as the research object, the COMSOL Multiphysics numerical simulation software was used to simulate and analyze the influence of inlet wind speed on the wind speed distribution on the tunnel section, and the wind speed distribution law of the semi circular arch tunnel section under different inlet wind speed conditions was obtained. The research results indicate that the wind speed contour is basically parallel to the tunnel wall, and the wind speed gradient near the tunnel wall is large, while the wind speed gradient in the middle of the tunnel is small. The thickness of the boundary layer decreases with increasing wind speed. The ratio of the maximum wind speed to the average wind speed of the tunnel section is approximately 1.2125. The distance between the average wind speed line of the semi circular arch tunnel and the roof is 10.76%~11.02% of the tunnel height, and the error between the simulation results and theoretical calculation results is within 4%. The research results provide strong support for precise measurement of the average wind speed at fixed points in coal mine underground tunnels.
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Hasan, Mohammed Munif, i Shabudin Mat. "Data Reduction Analysis on UTM-LST External Balance". International Journal for Research in Applied Science and Engineering Technology 10, nr 10 (31.10.2022): 952–59. http://dx.doi.org/10.22214/ijraset.2022.47097.
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Abstract: The effective use of wind-tunnel testing in determining aerodynamic properties of a body is very much dependent upon the reliability and speed with which wind-tunnel data can be reduced. The operating efficiency of the wind tunnels is substantially improved by the capability of providing lower aerodynamic coefficients in real time, or online, which decreases the expensive wind-tunnel time necessary for each test. This paper describes a system for presenting reduced wind-tunnel data in real time for UTM-LST. The requirements for data-handling equipment and data reduction procedures for wind tunnels are quite diverse, and depend upon the wind tunnel design and the type of tests for which they are used. The supersonic wind tunnels mentioned in this description have a variety of force-balance systems and are used for force tests, pressure tests, and other research projects. Consequently, the problems associated with in order to solve this diversity we build a computerized program where we can find the transformation of axis and aerodynamic characteristics at ease. This program can find the values of different aerodynamic coefficients with certain angle of attacks.
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Allan, M. R., K. J. Badcock, G. N. Barakos i B. E. Richards. "Wind-tunnel interference effects on a 70° delta wing". Aeronautical Journal 108, nr 1088 (październik 2004): 505–13. http://dx.doi.org/10.1017/s0001924000000336.
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Abstract This paper considers the effects of both wind-tunnel walls and a downstream support structure, on the aerodynamics of a 70° delta wing. A RANS model of the flow was used with the wind-tunnel walls and supports being modelled with inviscid wall boundary conditions. A consistent discretisation of the domain was employed such that grid dependence effects were consistent in all solutions, thus any differences occurring were due to varying boundary conditions (wall and support locations). Comparing solutions from wind-tunnel simulations and simulations with farfield conditions, it has been shown that the presence of tunnel walls moves the vortex breakdown location upstream. It has also been seen that vortex strength, helix angle, and mean incidence also increase, leading to a more upstream breakdown location in wind-tunnels. The secondary separation line was also observed to move outboards. It was observed that for high Reynolds numbers, with a support downstream of the wing, vortex breakdown can be delayed due to blockage effects providing the vortices do not impinge on the support This was observed to be the case for smaller supports also.
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Ma, Xiaojun, Yu Zhao, Xueying Wen i Jiujiu Chen. "Accessibility Study of a Compact Wind Tunnel with an Unequal Spacing Grid for the Outdoor Wind Environment". Buildings 12, nr 12 (9.12.2022): 2188. http://dx.doi.org/10.3390/buildings12122188.
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One of the key issues in architectural design and regional planning is to create a safe and comfortable outdoor building environment, which calls for more studies. Wind tunnel experiments and computational fluid dynamic (CFD) simulations are the primary methods for the current studies. The airflow and boundary conditions are controllable for the wind tunnel experiment, and the data is reliable. In most wind tunnel platforms, spires and roughness elements are applied to create the gradient wind of the atmospheric boundary layer, leading to the oversized, high construction cost, and complex operation. In this paper, in order to explore a simple method for measuring and studying the outdoor building wind environment using wind tunnels, a compact wind tunnel platform adopting grids with unequal spacing was designed and tested, based on the theoretical model of the atmospheric boundary layer. A comparison between the test results and the theoretical values indicated that this new wind tunnel platform could achieve a gradient wind field and is accessible in applying low-speed wind tunnels to the measurement and research of the building wind environment. The application case in a high-rise building of the central business district (CBD) region in Beijing, was presented in this paper. Compared with another analytical method, the CFD simulation, the compact wind tunnel revealed its applicability that could be used for predicting and evaluating the outdoor wind environment around the building. This compact wind tunnel is more flexible and convenient than the traditional ones, with a smaller size, easier construction and operation, and lower costs. Therefore, we suggest more applications of this compact wind tunnel platform in future experimental studies of outdoor wind environments.
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NISHIMURA, Hiroaki. "Wind Tunnel Experiment and Wind Tunnel Test". Wind Engineers, JAWE 39, nr 4 (2014): 333–34. http://dx.doi.org/10.5359/jawe.39.333.
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Flamand, Olivier, Philippe Delpech, Pierre Palier i Jean-Paul Bouchet. "Benefit of Wind Tunnels with Large Test Sections for Wind Engineering Applications". Mathematical Modelling in Civil Engineering 15, nr 2 (1.06.2019): 14–19. http://dx.doi.org/10.2478/mmce-2019-0005.
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Abstract Atmospheric Boundary layer wind tunnels (ABLWT) dedicated to building safety and comfort have been operated by CSTB in Nantes since 1971. Because ABLWT only deal with reduced scale models of real structures, the necessity of a larger wind tunnel, the Jules Verne Climatic wind tunnel (CWT), able to reproduce extreme wind loads on real scale structures arose in the years 80. Hence, it became a major European facility operating for improvement of the safety, quality and environmental impact of buildings and civil engineering works as well as products from industrial fields (transportation, energy…) with respect to strong winds and other climatic hazards. Both wind tunnel types, the ABLWT and the CWT are complementary and used for studying the effect of wind on the same structures at two different scales, when the effect of wind scaling is important. During the 2018 year, several modifications were made to the CWT facility. The atmospheric test section of the existing facility was elongated preserving the initial advantages, very large test section (approximately 120 m2) with wind velocity performance compatible with many applications (up to 90 km/h). This new test section makes it possible to simulate turbulent wind and driving rain testing. The sand winds capabilities have been maintained in the new design, despite the closed loop configuration, by fitting a filtering. The modifications of the wind tunnel geometry now offer a long test section upstream the turning vanes where a whole set of new tests can be carried out, as windmill field, natural ventilation of urban environments, slender structures (large bridges, pylons, cable transport systems,)
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Zhang, Ying Chao, Wei Ding, Zhe Zhang i Jie Li. "Comparison Research on Aerodynamic Drags and Pressure Coefficients of Reference Car Models in Automotive Wind Tunnel". Advanced Materials Research 989-994 (lipiec 2014): 2834–38. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.2834.
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The aerodynamic drags of different reference car models were investigated to calibrate the performance of the Automotive Wind Tunnel in Jilin University. The two kinds of reference models--MIRA and SAE reference car models were involved in this paper, considering the actual situation of the Automotive Wind Tunnel in Jilin University. The results of the research show that the Automotive Wind Tunnel in Jilin University can meet the demand for automotive wind tunnel tests and it can get the same performances as other wind tunnels have and reliable test data can be obtained in it.
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Wang, Fei, Xingsen He, Lin Xu, Shengzhong Zhao i Miaocheng Weng. "Train-Induced Unsteady Airflow in a Metro Tunnel with a Ventilation Shaft". Applied Sciences 14, nr 20 (10.10.2024): 9177. http://dx.doi.org/10.3390/app14209177.
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To ensure only one train operates in each ventilation section within an extra-long tunnel, a ventilation shaft was typically installed to divide the entire tunnel into multiple sections. Given the crucial role of piston wind in the metro tunnel environment and ventilation, a deeper understanding of train-induced unsteady airflow in a metro tunnel with a ventilation shaft is desirable. This study uses the unsteady flow theory of the Bernoulli equation to mathematically model piston wind in metro tunnels both with and without ventilation shafts. The influence of various shaft parameters on piston wind development is systematically analyzed. The results indicate that the shaft significantly impacts the piston wind. The maximum piston wind speed and ventilation rate in tunnels with ventilation shafts surpass those in tunnels without them. Moreover, shaft location and the cross-sectional area notably affect the maximum piston wind speed, ventilation rate, and airflow in the shaft, whereas shaft height has no significant effect. It is found that a ventilation shaft with a larger cross-sectional area positioned in the middle of the tunnel enhances the performance of piston ventilation.
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Vukovic, Djordje, i Dijana Damljanovic. "Thermal effects influencing measurements in a supersonic blowdown wind tunnel". Thermal Science 20, nr 6 (2016): 2101–12. http://dx.doi.org/10.2298/tsci160404175v.
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During a supersonic run of a blowdown wind tunnel, temperature of air in the test section drops which can affect planned measurements. Adverse thermal effects include variations of the Mach and Reynolds numbers, variation of airspeed, condensation of moisture on the model, change of characteristics of the instrumentation in the model, et cetera. Available data on thermal effects on instrumentation are pertaining primarily to long-run-duration wind tunnel facilities. In order to characterize such influences on instrumentation in the models, in short-run-duration blowdown wind tunnels, temperature measurements were made in the wing-panel-balance and main-balance spaces of two wind tunnel models tested in the T-38 wind tunnel. The measurements showed that model-interior temperature in a run increased at the beginning of the run, followed by a slower drop and, at the end of the run, by a large temperature drop. Panel-force balance was affected much more than the main balance. Ways of reducing the unwelcome thermal effects by instrumentation design and test planning are discussed.
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Stalker, R. J. "Modern developments in hypersonic wind tunnels". Aeronautical Journal 110, nr 1103 (styczeń 2006): 21–39. http://dx.doi.org/10.1017/s0001924000004346.
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AbstractThe development of new methods of producing hypersonic wind-tunnel flows at increasing velocities during the last few decades is reviewed with attention to airbreathing propulsion, hypervelocity aerodynamics and superorbital aerodynamics. The role of chemical reactions in these flows leads to use of a binary scaling simulation parameter, which can be related to the Reynolds number, and which demands that smaller wind tunnels require higher reservoir pressure levels for simulation of flight phenomena. The use of combustion heated vitiated wind tunnels for propulsive research is discussed, as well as the use of reflected shock tunnels for the same purpose. A flight experiment validating shock-tunnel results is described, and relevant developments in shock tunnel instrumentation are outlined. The use of shock tunnels for hypervelocity testing is reviewed, noting the role of driver gas contamination in determining test time, and presenting examples of air dissociation effects on model flows. Extending the hypervelocity testing range into the superorbital regime with useful test times is seen to be possible by use of expansion tube/tunnels with a free piston driver.
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Bak, Christian, Anders S. Olsen, Andreas Fischer, Oliver Lylloff, Robert Mikkelsen, Mac Gaunaa, Jimmie Beckerlee i in. "Wind tunnel benchmark tests of airfoils". Journal of Physics: Conference Series 2265, nr 2 (1.05.2022): 022097. http://dx.doi.org/10.1088/1742-6596/2265/2/022097.
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Abstract This paper describes a benchmark of four airfoils in the Poul la Cour Tunnel (PLCT). The wind tunnel, the corrections used and the method of making adapters for the airfoils are also described. Very good agreement was in general observed between the measurements in PLCT and in other high quality wind tunnels. Some deviations were seen, but they were mainly attributed to the differences in separation on the airfoil. Apart from the benchmarking, this paper also highlights the challenges in testing airfoils in general such as obtaining 2D flow on thick airfoils that inherently shows separated flow and how to make adapters for airfoils tested in other wind tunnels.
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Kato, Satoshi. "Wind Tunnel". Journal of the Society of Mechanical Engineers 103, nr 985 (2000): 824–25. http://dx.doi.org/10.1299/jsmemag.103.985_824.
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SHIGEMI, Masashi. "Wind Tunnel". Journal of the Society of Mechanical Engineers 107, nr 1024 (2004): 168–69. http://dx.doi.org/10.1299/jsmemag.107.1024_168.
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Shahidin, Haziq Idraki, Mohd Rosdzimin Abdul Rahman, Azam Che Idris i Mohd Rashdan Saad. "3D Printed Models vs Conventional Models: Comparison of Aerodynamic Performance for Wind Tunnel Experiments". Jurnal Kejuruteraan si4, nr 2 (31.10.2021): 101–4. http://dx.doi.org/10.17576/jkukm-2021-si4(2)-15.
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Traditionally, wind tunnel models are made of metal and the processes are very expensive. Since then, many researchers have been looking for new alternatives, hence 3D printing technology is the solution. Under right test conditions, 3D printed parts could be tested in a wind tunnel to get the aerodynamic performances. By using 3D printing technology, the cost and time can be significantly reduced to produce the wind tunnel models. This investigation was done to compare the aerodynamic performances which are drag and lift forces of the existing wind tunnel metal models with 3D printed wind tunnel models. Polylactic acid (PLA) was used as the printing materials by using two 3D printers which are Poseidon X and CR-10 S5. The wind tunnel testing covered the wind speed in the range of 0.57 m/s to 10.35 m/s at angle of-attack of 0°. Results from experiments show that the drag and lift forces of the 3D printed models show very close similarities with the metal models. It can be concluded that the wind tunnel models produced by using 3D printing technology can be used in wind tunnels for early testing.
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CHEN, Dan, Zhong WANG, Xiang LU, Chenlong LIN i Haitao PEI. "The control system design and study for continuous supersonic wind tunnel". Xibei Gongye Daxue Xuebao/Journal of Northwestern Polytechnical University 40, nr 1 (luty 2022): 167–74. http://dx.doi.org/10.1051/jnwpu/20224010167.
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As the first continuous supersonic wind tunnel in China, Mach number and total pressure are the most important flow field parameters of the wind tunnel, how to precise control and rapid and stable adjustment of total pressure and Mach number is the key in the design and construction of the wind tunnel control system. By analyzing the principle of parameter control of the wind tunnel flow field and the coupling relationship of each adjustment methods, the construction of continuous supersonic wind tunnel control system is constructed, and the solution measure of each key technical problem is given. The total pressure is precisely controlled by the segmented variable parameter fuzzy PI control algorithm, and then the wind tunnel operation control process design is carried out. Finally the wind tunnel blowing test is verified. The result shows that the accuracy of total pressure accuracy is better than 0.05%, the Mach number accuracy is better than 0.167 3, all the flow field parameter is greatly better than the design index, which proves that the design idea proposed in this paper is effective and can provide reference for the design and debugging of continuous supersonic wind tunnels.
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Vuković, Đorđe, i Dijana Damljanović. "A technique for reducing supersonic transient loads on internal wind tunnel balances". Tehnika 79, nr 2 (2024): 177–84. http://dx.doi.org/10.5937/tehnika2402177v.
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Design of slender supersonic missiles requires a comprehensive experimental support in the form of wind tunnel data for a wide range of flight parameters (angle of attack and Mach number). However, in supersonic wind tunnel testing, the problem exists of transient loads at the times of the starting and stopping of the supersonic flow. In the environments of pronounced transient loads, characteristic of blowdowin wind tunnels like the T-38 of the Military technical Institute in Belgrade, it is necessary to provide control of the use of internal wind tunnel balances in the permitted design load ranges. The presented technique is related to the definition and implementation of a methodology for reducing the transient loads on wind tunnel balances in supersonic wind tunnel tests. By limiting the clearance between the model and its tail support (sting) to a magnitude which permits normal tests, but results in model-support contact during the excessive loads, part of the loads is transferred to the support sting, relieving the balance. The technique improves control over the wind tunnel test process, improves measurement accuracy and prevents damage to sensitive instrumentation (wind tunnel balances).
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Ni, Yangqin, Mingnian Wang, Zhenghui Ge, Yuxuan Guo, Changling Han, Anmin Wang, Jingyu Chen i Tao Yan. "Prediction Method of Tunnel Natural Wind Based on Open-Source Meteorological Parameters". Processes 11, nr 1 (10.01.2023): 224. http://dx.doi.org/10.3390/pr11010224.
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The rational use of natural wind in extra-long tunnels for feedforward operation ventilation control can dramatically reduce tunnel operation costs. However, traditional tunnel natural wind calculation theory lacks a prediction function. This paper proposes a three-stage tunnel natural wind prediction method relying on the Yanglin Tunnel in Yunnan, China based on the massive meteorological parameters provided by the open-source national meteorological stations around the tunnel, which make up for the partial deficiency of the meteorological parameters of the tunnel portal. The multi-layer perceptron model (MLP) was used to predict the real-time meteorological parameters of the tunnel portal using the data from four national meteorological stations. The nonlinear autoregressive network model (NARX) was used to predict the meteorological parameters of the tunnel portal in the next period based on the predicted and measured real-time data. The natural wind speed in the tunnel was obtained by a theoretical calculation method using the predicted meteorological parameters. The final tunnel natural wind prediction results are in good agreement with the field measured data, which indicates that the research results of this paper can play a guiding role in the feedforward regulation of tunnel operation fans.
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Huang, Weihao, Yan Tong, Gangyu Lv, Baolian Dai i Tao Peng. "Dynamic evolutions of traffic wind influenced by ambient wind for urban road tunnel with shafts". E3S Web of Conferences 356 (2022): 02014. http://dx.doi.org/10.1051/e3sconf/202235602014.
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Urban road tunnels with shafts have been applied in some cities in China. Field measurements of Mofan Road Tunnel show that ambient wind is widespread and its influence on the ventilation efficiency of shaft is unclear. In this paper, the physical model of a three-lane 210 m (length) *12 m (width) *6 m (height) tunnel is studied, with three vehicles in each lane and a speed of 60 km/h. Three-dimensional CFD simulations on a 210 m long tunnel with double shafts is carried out by Fluent 6.3.26. Momentum equation and k-ε equation turbulence model are used for simulation analysis and dynamic grid technology is used to simulate vehicles driving. It is found that the ambient wind in tunnel has great influence on the flow field in tunnel and shaft. Number Ri is defined as the ratio of horizontal inertia force to vertical inertia force, revealing the conversion of horizontal inertia force to vertical inertia force.
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Du, Longhuan, Arganthaël Berson i Robert G. Dominy. "Aerofoil behaviour at high angles of attack and at Reynolds numbers appropriate for small wind turbines". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 229, nr 11 (8.09.2014): 2007–22. http://dx.doi.org/10.1177/0954406214550016.
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The aerodynamic characteristics of a NACA0018 aerofoil have been investigated experimentally for incidence angles ranging from [Formula: see text] to [Formula: see text] in closed-jet and open-jet wind tunnels with different blockage coefficients at Reynolds numbers from 60,000 to 140,000. The results provide a comprehensive data set for studying the performance of typical, small-scale Darrieus wind turbine blades which mainly operate at relatively low Reynolds number and experience extreme angles of attack, particularly during start-up. Measurements in both very high and very low blockage, open-jet wind tunnels capture a “second-stall” phenomenon at high angles of attack, but this behaviour is not observed in the closed-jet wind tunnel confirming the sensitivity of aerofoil performance at extreme incidence to wind tunnel configuration. Surface flow visualisation suggests that the “second-stall” occurs when the flow separation point near the leading edge of the aerofoil moves from the suction side to the pressure side which leads to a sudden change of wake structure. In the closed-jet wind tunnel, the tunnel walls constrain the wake and prevent the flow from switching from one regime to another. The measured data are also used to demonstrate that established wind tunnel blockage corrections break down under these extreme, post-stall angles of attack.
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Tan, Yinjun, Keli Wang, Zhiqiang Zhang, Zeyi Lu i Heng Zhang. "Study on the Effect of Natural Wind on the Smoke Spread Law of Extra-Long Tunnel Fires with Inclined Shafts for Air Supply and Exhaust". Buildings 14, nr 6 (23.05.2024): 1516. http://dx.doi.org/10.3390/buildings14061516.
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High-temperature smoke generated by tunnel fires is the most important factor causing casualties. To explore the influence of natural wind on fire smoke movement in an extra-long highway tunnel based on the Taihang Mountain Tunnel, the distribution law of natural wind in the tunnel was obtained by on-site monitoring of the meteorological conditions at the tunnel site. A three-dimensional fire dynamics tunnel model considering an inclined shaft smoke exhaust was established, and the influence of natural wind on tunnel temperature distribution, smoke spread and smoke exhaust efficiency was studied. The results show that the natural wind speed of the Taihang Mountain Tunnel is mainly concentrated at 0~3 m/s. The main wind direction of the natural wind on the left tunnel is opposite to the driving direction, and the distribution probability of the main wind direction in each section is 81.27% and 72.15%, respectively. The main wind direction of the right tunnel is the same as the driving direction, and the distribution probability of the main wind direction in each section is 56.78%, 69.73%, 67.32% and 64.65%, respectively. The negative natural wind can inhibit the smoke spread downstream of the smoke exhaust port, but it is not conducive to the smoke exhaust. The positive natural wind promotes the smoke spread to the downstream of the smoke exhaust port, and the larger the natural wind speed, the longer the spread length. Natural wind reduces the smoke exhaust efficiency. For positive or negative natural wind with a guaranteed rate of 70%, the smoke exhaust efficiency is reduced by 27.76% and 15.59%, respectively, compared with the condition without natural wind. The research results can provide a useful reference for the design of fire smoke exhausts and smoke control schemes in extra-long highway tunnels.
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Baker, Dirk V., i K. Beck George. "The Weed Tunnel: Building an Experimental Wind Tunnel". Weed Technology 22, nr 3 (wrzesień 2008): 549–52. http://dx.doi.org/10.1614/wt-07-162.1.
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Dispersal is a key component of plant population and community dynamics and the spread of weeds. Although many species of economic concern disperse via tumbleweed mechanisms, our ability to estimate relevant dispersal parameters can be hindered by the lack of a controlled environment that can be provided by a wind tunnel. Established wind tunnels are typically closed-circuit, clean systems and are therefore unsuitable for biological or ecological research. We designed and constructed a wind tunnel to estimate dispersal parameters for diffuse knapweed. Our design was a tunnel that utilizes the Venturi effect to obtain maximum flow velocity while pulling, rather than pushing, air through the test section. Flow velocity was continuously variable from 0 to 8 m/s, and the tunnel was equipped with instrumentation for measuring the force exerted on plants by wind. Our modular design provided a way to effectively estimate key parameters that govern the dispersal of tumbleweeds, and was readily constructed and stored in research facilities.
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Hasan, Inamul, R. Mukesh, P. Radha Krishnan, R. Srinath, Dhanya Prakash Babu i Negash Lemma Gurmu. "Wind Tunnel Testing and Validation of Helicopter Rotor Blades Using Additive Manufacturing". Advances in Materials Science and Engineering 2022 (21.09.2022): 1–13. http://dx.doi.org/10.1155/2022/4052208.
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This research paper aims to validate the aerodynamic performance of rotor blades using additive manufacturing techniques. Wind tunnel testing is a technique used to find the flow characteristics of the body. Computational fluid dynamics (CFD) techniques are used for aerodynamic analysis, and validation should be done using wind tunnel testing. In the aerodynamic testing of models, additive manufacturing techniques help in validating the results by making models easily for wind tunnels. Recent developments in additive manufacturing help in the aerodynamic testing of models in wind tunnels. The CFD analysis of helicopter rotor blades was analyzed in this research, and validation was done using additive manufacturing techniques. Computational analysis was carried out for static analysis for the forward speeds of Mach numbers 0.3, 0.4, and 0.5. The results obtained were satisfactory to the previous results and were validated with wind tunnel testing. Results proved that the error percentage was lower, and the computational analysis was valid. In this research, models were designed using the FDM technique for wind tunnel testing as it is cost-effective and easy to manufacture.
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Lara, Andrés, Jonathan Toledo i Robert Paul Salazar Romero. "Characterization, Design Testing and Numerical Modeling of a Subsonic-Low Speed Wind Tunnel". Ingeniería 27, nr 1 (4.01.2022): e17973. http://dx.doi.org/10.14483/23448393.17973.
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Context: Wind tunnels are essential devices in the study of flow properties through objects and scaled prototypes. This work presents a numerical study to characterize an existing wind tunnel, proposing modifications with the aim to improve the quality of the flow in the test chamber. Method: Experimental measurements of the inlet velocity and pressure distribution of a wind tunnel are nperformed. These empirical values are used as parameters to define boundary conditions in simulations. The Finite Element Method (FEM) at low speeds is implemented to determine the stream function by using a standard Galerkin method. Polynomial interpolations are employed to modify the contraction section design, and numerical simulations are performed in order to compare the numerical results of the flow for the existing and the modified wind tunnels. Results: Experimental measurements of the flow at the wind tunnel entrance are presented. The velocity field and distribution of thermodynamic variables inside the tunnel are numerically determined. This computations are useful since it is experimentally difficult to make measurements inside the channel. Additionally, numerical calculations of these variables are presented under modifications in the tunnel geometry. Conclusions: A comparison between these simulations show that laminar flow at low velocities can be modeled as incompressible and irrotational fluid under a bidimensional approximation along its longitudinal section. It is observed that modifications in the geometry of the tunnel can improve the flow in the test section of the wind tunnel in the laminar regime.
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Tsushima, Natsuki, Kenichi Saitoh, Hitoshi Arizono i Kazuyuki Nakakita. "Structural and Aeroelastic Studies of Wing Model with Metal Additive Manufacturing for Transonic Wind Tunnel Test by NACA 0008 Example". Aerospace 8, nr 8 (25.07.2021): 200. http://dx.doi.org/10.3390/aerospace8080200.
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Additive manufacturing (AM) technology has a potential to improve manufacturing costs and may help to achieve high-performance aerospace structures. One of the application candidates would be a wind tunnel wing model. A wing tunnel model requires sophisticated designs and precise fabrications for accurate experiments, which frequently increase manufacturing costs. A flutter wind tunnel testing, especially, requires a significant cost due to strict requirements in terms of structural and aeroelastic characteristics avoiding structural failures and producing a flutter within the wind tunnel test environment. The additive manufacturing technique may help to reduce the expensive testing cost and allows investigation of aeroelastic characteristics of new designs in aerospace structures as needed. In this paper, a metal wing model made with the additive manufacturing technique for a transonic flutter test is studied. Structural/aeroelastic characteristics of an additively manufactured wing model are evaluated numerically and experimentally. The transonic wind tunnel experiment demonstrated the feasibility of the metal AM-based wings in a transonic flutter wind tunnel testing showing the capability to provide reliable experimental data, which was consistent with numerical solutions.
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Orosa, José A., Enrique J. García-Bustelo i Diego Vergara. "A New Procedure to Design an Open Circuit Blowing Subsonic Moist-Air Wind Tunnel". Applied Sciences 13, nr 19 (6.10.2023): 11021. http://dx.doi.org/10.3390/app131911021.
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The present research work shows how a functional subsonic moist-air wind tunnel has been designed. Although this type of wind tunnel has never been developed to date, it is particularly interesting to develop a satisfactory design of feasibility under moist air conditions. Low-speed vertical-axis wind turbines employ different kinds of rotors, such as Savonius, Darrieus, and H-rotor. All these wind turbines present clear advantages, e.g., the horizontal-axis wind turbines are omnidirectional. This means they can work under different wind directions, need lower maintenance, and begin working under low wind speeds of 3 m/s. Recently, a new application of wind concentrators enabled the vertical-axis wind turbines to improve their performance coefficient based on new concepts like moist air phase change, which are being analysed to improve energy conversion. Thus, expectations were raised to design a suitable wind tunnel that accounts for the relative humidity of moist air. An initial prototype showed that the behaviour of open wind tunnels where the relative humidity of moist air was controlled by an adiabatic evaporative process was satisfactory. However, for such wind tunnels, certain improvements like computer control systems would need to be developed.
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Yu, Wenshan, Beichen Su, Zhengzhou Rao, Hengxin Pan i Luping Zhao. "Genetic Algorithm-Based Mach Number Control of Multi-Mode Wind Tunnel Flow Fields". Processes 10, nr 10 (9.10.2022): 2038. http://dx.doi.org/10.3390/pr10102038.
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There are unfavorable conditions such as constantly changing working conditions and frequent disturbances that affect Mach number control in wind tunnel flow fields. As the proportional, integral and differential (PID) parameters need to be re-tuned for each working conditions of a wind tunnel, the operational costs of wind tunnels are very high. Therefore, to lower these costs, a genetic algorithm was utilized to tune the PID parameters to achieve Mach number control of a multi-mode wind tunnel flow field. In this paper, firstly, models for the multi-mode wind tunnel were established; secondly, a PID control system was designed based on the genetic algorithm and the control effects of the proposed PID control system were verified by simulations and were compared with the effects of a PSO tuning PID control system.
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Liu, Shanhe, Zhiwen Luo, Keer Zhang i Jian Hang. "Natural Ventilation of a Small-Scale Road Tunnel by Wind Catchers: A CFD Simulation Study". Atmosphere 9, nr 10 (20.10.2018): 411. http://dx.doi.org/10.3390/atmos9100411.
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Providing efficient ventilation in road tunnels is essential to prevent severe air pollution exposure for both drivers and pedestrians in such enclosed spaces with heavy vehicle emissions. Longitudinal ventilation methods like commercial jet fans have been widely applied and confirmed to be effective for introducing external fresh air into road tunnels that are shorter than 3 km. However, operating tunnel jet fans is energy consuming. Therefore, for small-scale (~100 m–1 km) road tunnels, mechanical ventilation methods might be highly energetically expensive and unaffordable. Many studies have found that the use of wind catchers could improve buildings’ natural ventilation, but their effect on improving natural ventilation in small-scale road tunnels has, hitherto, rarely been studied. This paper, therefore, aims to quantify the influence of style and arrangement of one-sided flat-roof wind catchers on ventilation performance in a road tunnel. The concept of intake fraction (IF) is applied for ventilation and pollutant exposure assessment in the overall tunnel and for pedestrian regions. Computational fluid dynamics (CFD) methodology with a standard k-epsilon turbulence model is used to perform a three-dimensional (3D) turbulent flow simulation, and CFD results have been validated by wind-tunnel experiments for building cross ventilation. Results show that the introduction of wind catchers would significantly enhance wind speed at pedestrian level, but a negative velocity reduction effect and a near-catcher recirculation zone can also be found. A special downstream vortex extending along the downstream tunnel is found, helping remove the accumulated pollutants away from the low-level pedestrian sides. Both wind catcher style and arrangement would significantly influence the ventilation performance in the tunnel. Compared to long-catcher designs, short-catchers would be more effective for providing fresh air to pedestrian sides due to a weaker upstream velocity reduction effect and smaller near-catcher recirculation zone. In long-catcher cases, IF increases to 1.13 ppm when the wind catcher is positioned 240 m away from the tunnel entrance, which is almost twice that in short-catcher cases. For the effects of catcher arrangements, single, short-catcher, span-wise, shifting would not help dilute pollutants effectively. Generally, a design involving a double short-catcher in a parallel arrangement is the most recommended, with the smallest IF, i.e., 61% of that in the tunnel without wind catchers (0.36 ppm).
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Hrúz, Michal, Pavol Pecho i Martin Bugaj. "Design procedure and honeycomb screen implementation to the air transtport department’s subsonic wind tunnel". AEROjournal 16, nr 2 (2020): 3–8. http://dx.doi.org/10.26552/aer.c.2020.2.1.
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Wind tunnels are the most widely used tools when comes to validation of Reynold number. Most of wind tunnels use various air straighteners or flow conditioners to achieve as most unified air flow as it’s possible. This article deals with design and creation procedure of air flow straightener – honeycomb screen. Based on mathematical relations and empirical experience defines dimensions and characteristics for subsonic wind tunnel of the Air Transport Department of University of Žilina. Wind tunnel equipped with a suitable screen provides more relevant and accurate data, which are crucial for final validation of results of test objects.
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Kok-Hoe Wong, Weldon Lai, Jing-Hong Ng, Ahmad Fazlizan, Kamaruzzaman Sopian i Niranjan Sahoo. "Open-Loop Subsonic Suction Type Wind Tunnel: Design, Simulation, Build and Test". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 105, nr 2 (1.06.2023): 204. http://dx.doi.org/10.37934/arfmts.105.2.204223.
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The technological advancement in drones, unmanned aerial vehicles (UAV), wind turbines, and airfoil research has grown rapidly since last decade. Computational fluid dynamics (CFD) analysis is commonly used to study the airflow around a body. Yet, the wind tunnel is an essential instrument in aerodynamic research; however, a commercial wind tunnel normally comes with a small test section and incurs high investment costs. This paper presents the development of a low-cost subsonic open-loop wind tunnel for research and education purposes. The suction-type wind tunnel is intentionally designed with a large test section of 1 m2 and in modular form where each section can be rectified according to the application and for different wind tunnel parameter studies. The detailed design steps, fabrication method, and build of the tunnel are described, along with the flow analysis that has been conducted. Furthermore, a 3D CFD simulation has been performed to simulate the flow condition of the wind tunnel where a good agreement between the simulation and flow measurement is observed. The potential root cause for discrepancy and comparisons with other wind tunnels are discussed. From the preliminary test, wind flow velocity and the turbulence intensity (TI) obtained from the flow measurement are 5.16 m/s and 3.14 % respectively. The TI is less than < 5%, which is considered a medium turbulence case that is good to study the flow around small-scale specimens like micro wind turbines and UAVs.
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Cooper, Kevin R., Edzard Mercker i Jürg Müller. "The necessity for boundary corrections in a standard practice for the open-jet wind tunnel testing of automobiles". Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, nr 9 (26.04.2017): 1245–73. http://dx.doi.org/10.1177/0954407017701287.
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This paper is intended to provide a summary of the necessary adjustments required for road-representative open-jet wind tunnel measurements on automobiles. The open-jet wind tunnel provides accurate measurements, but they are made in a finite-sized jet that differs from the unconfined open-road conditions. Furthermore, measurements on a given automobile made in different open-jet wind tunnels disagree with each other, and with measurements in closed-wall wind tunnels that were corrected for the influences of their solid boundaries. There appears to be reticence at some company levels to making ‘corrections’ to open-jet measurements. Perhaps non-specialist managers think that the need for a ‘correction’ means an erroneous measurement. It does not! Any high-quality wind tunnel measurement is accurate, but it needs to be ‘calibrated’ to on-road conditions through an appropriate set of procedures. Closed-wall wind tunnels measure higher drag coefficients, in comparison with those in an unconstrained on-road flow. Open-jet wind tunnels frequently measure a lower value. The closed-wall adjustments lower the drag coefficient to the unconstrained value. Open-jet adjustments should also adjust the drag coefficient to the same unconstrained value. This paper explores the range of effects from the finite jet and elucidates the effectiveness of a two-measurement correction procedure. It is shown that not every data point must be measured twice, only a small selected subset. Since approximately 20% of tunnel occupancy is in the fan-on condition, then the additional cost of correct accurate on-road-equivalent data is low.
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Raupach, MR, i JF Leys. "Aerodynamics of a portable wind erosion tunnel for measuring soil erodibility by wind". Soil Research 28, nr 2 (1990): 177. http://dx.doi.org/10.1071/sr9900177.
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Portable wind erosion tunnels must satisfy several aerodynamic criteria to ensure that the flow within them acceptably reproduces the atmospheric flow causing natural wind erosion. We define these criteria and use them to assess the flow and turbulence in two alternative designs of portable wind erosion tunnel: the first has a working section with an approximately triangular, 'tent-shaped' cross section, while the second has a conventional, rectangular working section. The measurements were made with Pitot-static tubes and X-configuration hot-wire anemometers, over stable (non-eroding) rough surfaces, mainly mowed grass of height 1 cm. We found that, with careful attention to flow conditioning elements such as honeycombs and tripping fences, an acceptable flow can be achieved in the rectangular tunnel. The flow in the tent-shaped tunnel is less satisfactory, exhibiting departures from the logarithmic wind profile law which depend on the surface roughness.
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Vitalii, Yanovych, i Duda Daniel. "Structural Deformation of a Running Wind Tunnel Measured By Optical Scanning". Strojnícky časopis - Journal of Mechanical Engineering 70, nr 2 (1.11.2020): 181–96. http://dx.doi.org/10.2478/scjme-2020-0030.
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AbstractNowadays, the development of wind tunnels for the study of various aerodynamic phenomena is actively developing. It is possible to generate a highly laminar flow only under the condition of structural stability of the construction parts of the wind tunnel under the action of sharp pressure drops. The aim of this research is to investigate the deformation and displacement of the structural parts of the developed wind tunnel capacity of 55 kW depending on the velocity of the generated airflow. To estimate the amount of deformation and mutual displacement of the structural elements of the wind tunnel depending on the airflow velocity, we used the ARAMIS optical system.
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Wu, Hao, Yujian Zhong, Wei Xu, Wangshuaiyin Shi, Xinghao Shi i Tong Liu. "Experimental Investigation of Ground and Air Temperature Fields of a Cold-Region Road Tunnel in NW China". Advances in Civil Engineering 2020 (22.07.2020): 1–13. http://dx.doi.org/10.1155/2020/4732490.
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To fully understand the temperature distribution of cold regions and the variation law of temperature fields in cold-region tunnels, this paper presents a case-history study on a tunnel located on the eastern Qinghai-Tibet Plateau, China. The conclusion is as follows: the temperature outside the tunnel and the ambient temperature are affected by wind speed and light. The law of the temperature field in the tunnel is greatly affected by wind speed and wind direction. According to the field test, the wind speed in the tunnel is about 2.8 m/s in winter, and the daily average temperature at the exit of the tunnel is basically lower than that at the entrance. From the central to the entrance, the temperature in the tunnel decreases by 0.11°C every 10 meters along the longitudinal direction; from the central to the exit, the temperature in the tunnel increases by 0.07°C every 10 meters. In this regard, for the problems of lining frost damage and central drainage pipe freezing, it is suggested to adopt the way of heating and drainage, but heating the freezing area outside the drainage pipe should be avoided. The test results can provide references for the design, construction, and research of the temperature field of the tunnel antifreezing system in the cold region. It is hoped that the test results can be useful in the design and construction of frost damage prevention systems and the investigation of temperature fields in cold-region tunnels.
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Čeheľová, Dagmara, Michal Franek i Boris Bielek. "Atmospheric Boundary Layer Wind Tunnel of Slovak University of Technology in Bratislava". Applied Mechanics and Materials 887 (styczeń 2019): 419–27. http://dx.doi.org/10.4028/www.scientific.net/amm.887.419.
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Aerodynamics is a relatively young scientific discipline, which started developing in the 50´s of last century. There are known several methods for calculating and measuring of the aerodynamic variables – in-situ measurements, wind tunnel measurements, CFD simulations and calculations according to national standards. Each method has its advantages and disadvantages. Nowadays a large focus is on experimental verifying the findings achieved with calculations help and CFD simulations. One of the verification possibilities are measurements in wind tunnels. The submitted paper deals with construction and using of the wind tunnel by the Slovak University of Technology in Bratislava. This device was put into operation after experimental verification in 2012, so this wind tunnel is one of the newest of its kind in Europe. The concept of the construction of individual structural elements and the wind tunnel parts has been designed in collaboration with the Aeronautical Research and Test Institute (Czech Republic) and was based on previous made analysis of aerodynamic tunnels. Its structure was designed and realized by Konštrukta Industry (Slovak Republic). We could it characterized as atmospheric boundary layer wind tunnel with open test section. It is unique with two test sections – front and back measuring space, where the front measuring space is used for uniform flow and the back measuring space is used for turbulent flow. That is why it is not only usable in the civil engineering sector (buildings, bridges, chimneys etc.), but also in city urbanism (pedestrian wind comfort and wind safety, dispersion of air pollutants), aircraft and automotive industries.
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Nachaiyaphum, Kwanjai, i Chonlatee Photong. "An electric power generation improvement for small Savonius wind turbines under low-speed wind". Indonesian Journal of Electrical Engineering and Computer Science 29, nr 2 (1.02.2023): 618. http://dx.doi.org/10.11591/ijeecs.v29.i2.pp618-625.
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<p>Savonius wind turbines have advantages of self-rotating at low speed wind, high starting torque, and less noise generation. However, they have low electric power generation capacity. This paper presents electric power generation improvement for small Savonius wind turbines when operating at low-speed wind of 1-6 m/s by using optimal Bach-type blades, twist blades and a wind tunnel. The turbine prototypes with the optimum diameter and height of 32 cm were developed with 3 different blade types: conventional semicircular blades, Bach-type blades and twisted 15° blades and a wind tunnel. The experimental results showed that the Savonius wind turbine with Bach-type generated highest electric voltage, which was 19.3% and 7.6% higher compared to conventional blades and twisted 15° blades. The additional wind tunnel could improve electric power generation efficiency by approximately 21.4% compared to the turbines without the tunnels.</p>
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Teo, Z. W., T. H. New, Shiya Li, T. Pfeiffer, B. Nagel i V. Gollnick. "Wind tunnel testing of additive manufactured aircraft components". Rapid Prototyping Journal 24, nr 5 (9.07.2018): 886–93. http://dx.doi.org/10.1108/rpj-06-2016-0103.
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Purpose This paper aims to report on the physical distortions associated with the use of additive manufactured components for wind tunnel testing and procedures adopted to correct for them. Design/methodology/approach Wings of a joined-wing test aircraft configuration were fabricated with additive manufacturing and tested in a subsonic closed-loop wind tunnel. Wing deflections were observed during testing and quantified using image-processing procedures. These quantified deflections were then incorporated into numerical simulations and results had agreed with wind tunnel measurement results. Findings Additive manufacturing provides cost-effective wing components for wind tunnel test components with fast turn-around time. They can be used with confidence if the wing deflections could be accounted for systematically and accurately, especially at the region of aerodynamic stall. Research limitations/implications Significant wing flutter and unsteady deflections were encountered at higher test velocities and pitch angles. This reduced the accuracy in which the wing deflections could be corrected. Additionally, wing twists could not be quantified as effectively because of camera perspectives. Originality/value This paper shows that additive manufacturing can be used to fabricate aircraft test components with satisfactory strength and quantifiable deflections for wind tunnel testing, especially when the designs are significantly complex and thin.
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Maturkanič, Dušan. "EFFECT OF THE FLOW FIELD DEFORMATION IN THE WIND TUNNEL ON THE AERODYNAMIC COEFFICIENTS". Acta Polytechnica 55, nr 3 (30.06.2015): 177–86. http://dx.doi.org/10.14311/ap.2015.55.0177.
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The flow field quality has a principal signification at wind tunnel measurement. The creation of the flow field of air by fan leads to the rotation of entire flow field which is, moreover, deformed at the bends of the wind tunnel with close circulation. Despite the wind tunnels are equipped with the devices which eliminate these non-uniformities, in the most of cases, the air flow field has not ideal parameters in the test section. For the evaluation of the measured results of the model in the wind tunnel, the character of flow field deformation is necessary. The following text describes the possible general forms of the flow field nonuniformity and their effect on the aerodynamic coefficients calculation.
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Shindo, Shojiro. "Wind Tunnel Testing". Journal of the Visualization Society of Japan 15, Supplement1 (1995): 277–80. http://dx.doi.org/10.3154/jvs.15.supplement1_277.
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TSUTSUMI, Takuya. "Snowdrift Wind tunnel". Wind Engineers, JAWE 34, nr 1 (2009): 36–41. http://dx.doi.org/10.5359/jawe.34.36.
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Starr, Rogers F. "Environmental wind tunnel". Journal of the Acoustical Society of America 100, nr 6 (1996): 3485. http://dx.doi.org/10.1121/1.417303.
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Starr, Rogers F. "Environmental wind tunnel". Journal of the Acoustical Society of America 100, nr 4 (1996): 1941. http://dx.doi.org/10.1121/1.417881.
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Atieh, Ahmad, Samir Al Shariff i Naseer Ahmed. "Novel wind tunnel". Sustainable Cities and Society 25 (sierpień 2016): 102–7. http://dx.doi.org/10.1016/j.scs.2016.02.002.
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Setiawan, M. Yasep, Andre Kurniawan, Ichsan, Toto Sugiarto, Nuzul Hidayat, Edy Susanto, Masykur i Miswardi. "Subsonic Wind Tunnels Air Speed Control Devices Base on Arduino Controller". E3S Web of Conferences 500 (2024): 03026. http://dx.doi.org/10.1051/e3sconf/202450003026.
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This study discusses the process of making an airspeed control device for wind tunnels using Arduino as the main component of the controller unit. Wind tunnel testing is carried out at varying airspeeds to obtain optimal results. The fan motor is not equipped with an air speed controller as an airflow generator. This research aims to make a tool that can control wind tunnel airspeed according to the testing needs. This research was conducted using the research and development method. The power supply voltage output is set at 11.19 Volts as the Arduino voltage source, and for other components such as LCDs, servo motors, relay modules, and anemometer sensors supplied from the Arduino mainboard plus and arranged in parallel with the power supply source reduced using a stepdown to 5.069 Volts. This subsonic wind tunnel's airflow speed control device can regulate the speed from 10 m/s to 13 m/s stably. This speed meets the requirements of a subsonic wind tunnel and can be used to visualize the airflow in the wind tunnel.
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Zhang, Zheng Yu, Xu Hui Huang, Jiang Yin i Han Xuan Lai. "Videogrammetric Techniques for Wind Tunnel Testing and Applications". Advanced Materials Research 986-987 (lipiec 2014): 1629–33. http://dx.doi.org/10.4028/www.scientific.net/amr.986-987.1629.
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Videogrammetric measurement is a research focus for the organizations of wind tunnel test because of its no special requirements on the test model, its key techniques for the vibration environment of the high speed wind tunnel are introduced by this paper, such as the solution of exterior parameters with big-angle large overlap, the algorithm of image processing for extracting marked point, the method of camera calibration and wave-front distortion field measurement. The great requirements and application prospects of videogrammetry in wind tunnel fine testing have been demonstrated by several practice experiments, including to measure test model’s angle of attack, dynamic deformations and wave-front distortion field in high speed wind tunnels whose test section size is 2 meters.
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Yanovych, Viatlii, i Daniel Duda. "Using ARAMIS system for measurement of structural stability of running wind tunnel". MATEC Web of Conferences 328 (2020): 01003. http://dx.doi.org/10.1051/matecconf/202032801003.
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Wind tunnels are popularly used to study various aerodynamic phenomena. Their design significantly influences the quality of the created airflow. During the flow generation, the construction parts of the wind tunnel to get deformed due to pressure variations. This phenomenon significantly complicates the creation of high-level laminar flow and worsens the results of experimental studies. The main purpose of this work is to investigate the effect of a sharp change in flow velocity on the structural stability of parts of a wind tunnel with a capacity of 55 kW. For experimental studies, we used the ARAMIS optical measurement system. Using it, we estimated the amount of deformation and mutual displacement of parts of the running wind tunnel at a flow rate of 76 m·s-1.
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Frechen, F. B., M. Frey, M. Wett i C. Löser. "Aerodynamic performance of a low-speed wind tunnel". Water Science and Technology 50, nr 4 (1.08.2004): 57–64. http://dx.doi.org/10.2166/wst.2004.0220.
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The determination of the odour mass flow emitted from a source is a very important step and forms the basis for all subsequent considerations and calculations. Wastewater treatment plants, as well as waste treatment facilities, consist of different kinds of odour sources. Unfortunately, most of the sources are passive sources, where no outward air flow-rate can be measured, but where odorants are obviously emitted. Thus, a type of sampling is required that allows to measure the emitted odour flow-rate (OFR). To achieve this, different methods are in use worldwide. Besides indirect methods, such as micrometeorological atmospheric dispersion models, which have not been used in Germany (in other countries due to different problems, direct methods are also used). Direct measurements include hood methods, commonly divided into static flux chambers, dynamic flux chambers and wind tunnels. The wind tunnel that we have been operating in principle since 1983 is different from all subsequent presented wind tunnels, in that we operate it at a considerably lower wind speed than the others. To describe the behaviour of this wind tunnel, measurement of the flow pattern in this low-speed tunnel are under way, and some initial results are presented here.
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Dou, Bingzheng, Zhanpei Yang, Michele Guala, Timing Qu, Liping Lei i Pan Zeng. "Comparison of Different Driving Modes for the Wind Turbine Wake in Wind Tunnels". Energies 13, nr 8 (14.04.2020): 1915. http://dx.doi.org/10.3390/en13081915.
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The wake of upstream wind turbine is known to affect the operation of downstream turbines and the overall efficiency of the wind farm. Wind tunnel experiments provide relevant information for understanding and modeling the wake and its dependency on the turbine operating conditions. There are always two main driving modes to operate turbines in a wake experiment: (1) the turbine rotor is driven and controlled by a motor, defined active driving mode; (2) the rotor is driven by the incoming wind and subject to a drag torque, defined passive driving mode. The effect of the varying driving mode on the turbine wake is explored in this study. The mean wake velocities, turbulence intensities, skewness and kurtosis of the velocity time-series estimated from hot-wire anemometry data, were obtained at various downstream locations, in a uniform incoming flow wind tunnel and in an atmospheric boundary layer wind tunnel. The results show that there is not a significant difference in the mean wake velocity between these two driving modes. An acceptable agreement is observed in the comparison of wake turbulence intensity and higher-order statistics in the two wind tunnels.