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Fly higher, faster, preserve the life of test pilots and passengers, many challenges faced by man since the dawn of the twentieth century, with aviation pioneers. Contemporary of the first aerial exploits, wind tunnels, artificially recreating conditions encountered during the flight, have powerfully contributed to the progress of aeronautics.
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... Lapresle, collaborator and successor of Eiffel at the Auteuil wind tunnel, designed, at the request of the Air Ministry, the large Chalais-Meudon wind tunnel (Hauts-de-Seine) that had been built between 1932 and 1934 for testing full-scale airplanes (see Figs. 7 and 8). It was equipped with a collector with a reduction ratio of 3.5, with a mouth of 350 m 2 that captures the outside air and allows it to reach a velocity of 180 km/h in the inlet test section of 100 m 2 . The diffuser, a giant tube shaped like a truncated cone (elliptical section, 10 m of vertical axis and horizontal axis of 18 m), is ...
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... This long and successful career earned him significant wealth, and towards the end of his life, he decided to invest in the emerging research field of "aviation." In 1909, he built one of the first wind tunnels dedicated to the study of "aerodynamics" at the base of his famous tower (Chanetz, B. 2017). Eiffel completed this wind tunnel and began experiments in 1909. ...
... Wind tunnel tests have many applications, some of which are calculating wind loads on buildings and investigating pollutant dispersion in urban street canyons, wind comfort at the pedestrian street level, and wind turbine integration in urban areas. Moreover, wind turbine test results could be used for validating data produced by other wind assessment tools [21,[58][59][60][61][62][63]. It could be argued that using wind tunnel tests at the early stages of the design gives more flexibility for investigating design alternatives to reach the optimum design solution [21]. ...
... Moreover, wind turbine test results could be used for validating data produced by other wind assessment tools [21,[58][59][60][61][62][63]. It could be argued that using wind tunnel tests at the early stages of the design gives more flexibility for investigating design alternatives to reach the optimum design solution [21]. ...
... They are also referred to as scale modelling or physical experiments. Using wind tunnels for testing the wind flow is well established in aerodynamics due to the fact that for a long time, they have been tested, validated, and produced reliable results [60]. When wind tunnels were used for urban wind flow applications, they had to be developed according to the complexity of the urban wind flow, which is different from the flow in aeronautic engineering applications where the flow is considered still. ...
Due to the complex nature of the built environment, urban wind flow is unpredictable and characterised by high levels of turbulence and low mean wind speed. Yet, there is a potential for harnessing urban wind power by carefully integrating wind turbines within the built environment at the optimum locations. This requires a thorough investigation of wind resources to use the suitable wind turbine technology at the correct location—thus, the need for an accurate assessment of wind resources at the proposed site. This paper reviews the commonly used wind assessment tools for the urban wind flow to identify the optimum tool to be used prior to integrating wind turbines in urban areas. In situ measurements, wind tunnel tests, and CFD simulations are analysed and reviewed through their advantages and disadvantages in assessing urban wind flows. The literature shows that CFD simulations are favoured over other most commonly used tools because the tool is relatively easier to use, more efficient in comparing alternative design solutions, and can effectively communicate data visually. The paper concludes with recommendations on best practice guidelines for using CFD simulation in assessing the wind flow within the built environment and emphasises the importance of validating CFD simulation results by other available tools to avoid any associated uncertainties.
... The main goal of our project was to achieve laminar fluid motion inside the test section of a wind tunnel, for which we used different sections, i.e., Contraction chamber, diffuser, and settling chamber [9]. The main role of the contraction chamber is to increase the mean velocity, which results in low air pressure and more energy-efficient wind tunnel operation [10]. We also want fewer pressure losses, and contractions play an important role in reducing pressure losses. ...
... The program used to obtain the readings from the load cells is as follows: #include "HX711.h" #include "Megatronics_pk_lcd.h" Megatronics_pk_lcd lcd (10,9,7,8) ...
The design and fabrication of a low-speed wind tunnel (LSWT), which is a critical component for testing and comprehending aircraft aerodynamics, is presented in this study. Despite the increasing prominence of computational fluid dynamics (CFDs) in manufacturing engineering, wind tunnels remain essential for the intricate development of aircraft and automobile designs with complex flow interactions. Using SolidWorks, we focused on controlling flow turbulence approaching the test section, emphasizing performance and quality parameters. The construction of the wind tunnel used plywood with an axial fan regulating the airspeed, and Arduino facilitated data acquisition. The drag and lift on the Y Clerk Airfoil were quantified by two load cells along the XY-axis, complemented by a Pitot Static Tube and a multitube inclined plane manometer for pressure and velocity calculation. Fusion 360 simulation software was used to analyze pressure and velocity profiles at speeds ranging from 10 to 20 m/s, providing a comprehensive quantitative evaluation of the wind tunnel’s capabilities. By emphasizing both design innovation and quantitative performance metrics, this study underscores the continuing significance of wind tunnels in engineering.
... Types of wind tunnel blowers are the most flexible because the fan is located at the inlet of the tunnel, so the test section can be easily interchanged or modified without significantly disturbing flow. Furthermore, the fan's performance installed at the inlet end is not affected by disturbed flow from the working section [8,9]. ...
A wind tunnel is needed for a lot of research and model testing in the field of engineering design. Commercial wind tunnels are large and expensive, making them unsuitable for small-scale aerodynamic model testing. This work aims to experimentally investigate the effects of flow, noise, and vibration on constructing and designing a low-speed wind tunnel structure. The flow uniformity in the wind tunnel has been tested by measuring the velocity profiles inside the empty test section with a pitot-static tube at various fan frequencies. The experiment results showed a good flow uniformity of more than 90% across the test section area, and the maximum wind velocity achieved was about 25.1 m/s. Due to the stability of the flow near the exit test section, the vibration measurement revealed that the entrance portion has larger vibration fluctuations than the exit part. Furthermore, as the axial fan frequency increases, the noise level increases. At 40 Hz, the noise level enters the hazardous zone, which has an impact on the person who performs the measurement process. The resonance of the wind tunnel structure is an important measurement test that affects vibration measurement.
... Yüzyılın başlarında yaygınlaşmış ve günümüzde de sadece havacılık ve uzay araştırmalarıyla sınırlı kalmayıp geniş bir kullanım alanına sahiptir. Ancak rüzgâr tüneli deneylerinde oluşturulan deney ortamı modelden modele değişmekte olduğundan her bir konsept için ayrı bir ortam oluşturma zorunluluğu içerdiğinden dolayı oldukça pahalıdır ve zaman kaybına neden olmaktadır [13]. Bilgisayar teknolojisindeki hızlı yükseliş sayesinde, yüksek konfigürasyona sahip bilgisayarlarla birlikte hesaplama metotlarının da aynı hızda gelişmesiyle; rüzgâr tüneli deneylerinde günler aylar sürecek akış deneyleri ve hesaplamaları daha kısa sürede yapılabilmektedir. ...
Vehicles that operate at altitudes close to the sea surface by taking advantage of the ground effect enable us to overcome the hydrodynamic force exerted by the water on the vehicle, allowing us to reach general aviation speeds, while also making it possible to carry more cargo than an aircraft by taking advantage of the ground effect. In this article, the NACA 4412 profile, which has a wide usage area, high lift/drag ratio and a flat bottom surface, has been chosen as a wing concept for a hoverwing vehicle that operates by making use of ground effect. Turbulence modeling was carried out at flight altitudes where it would be exposed to ground effect with a speed of 22.22 m/s and Re=4,068x106. While the height to the ground was decreased by 0.1 starting from the height of 1 chord, the angle of attack was increased up to 10 degrees in increments of 2 degree, starting from 0 degrees, and computational fluid dynamics analyzes were performed in 2D in the Realizable K-Epsilon experimental model with the help of ANSYS Fluent. As a result of the analyzes made, the highest lift/drag value was obtained as 50 at an angle of attack of 4 degrees and at a height corresponding to 0.1 chord value.
... To produce the plant samples with their properties as a model on a small scale is very difficult and almost impossible, so the investigation was done in a fully turbulent wind tunnel. Eiffel's design (Chanetz, 2017) features a simple arrangement of the wind tunnel that has the benefit of expelling contamination or torn leaves out of the tunnel. Due to the atypical positioning of the ventilator at the air intake, the ventilator is protected against torn-off plant parts. ...
Overgrown rope façades offer a space-saving possibility to make cities greener while counteracting the effect of the urban heat island (UHI). Unfortunately, there are no design models that adequately characterise the interaction between wind and plants for the calculation of wind loads. In the preceding study about overgrown rope façades (Arnold et al., 2021), a design model was deduced from flow force studies on trees and a drag coefficient for plants on overgrown rope façades was derived from drag resistance measurements of deciduous trees. This drag coefficient has not been validated. In this study, wind load tests in a turbulent wind tunnel were performed on five climbing plants to validate the drag coefficient. For this purpose, a prototype of a turbulent wind tunnel with an active grid that simulates gusts for a chaotic turbulent flow was built and various overgrown rope samples were measured. Based on the measured data, the 95% characteristic value of the drag coefficients was calculated using a statistical method. These drag coefficients can be applied to buildings at different speeds by means of E-values and B-values, thus allowing the design optimisation of plant climbing systems. This work does not deal with the interaction between the façade surface and overgrown rope plant in front of the façade, which requires further research.
... This suction wind tunnel ensures less interferences between the fan and the measurement object compared to a blowing wind tunnel. 25,26 The wall of the wind tunnel test section was slotted in order to reduce wall interferences. Furthermore, a 12-m-long movable net prolongates the inlet section to improve the flow quality, as seen in Figure 2 The rotational rate and the total sound pressure level of the ambient noise scales linearly with the wind velocity ( Table 2). ...
An experimental investigation on scaled wind turbine models in a wind tunnel with a microphone array is presented. Our study focuses on the localization and quantification of aerodynamic noise sources on rotating wind turbine blades with the aim of identifying the contributing factors that have an impact on the source spectra. Therefore, wind tunnel measurements were conducted for three different blade geometries (NACA 4412 shape, Clark-Y shape, and sickle shape), five pitch angles between −2° and +8° and five wind velocities between 5 and 13 mŝ−1. For the localization of rotating sound sources with a microphone array, a rotating beamforming method based on the acoustic ray method is used. The Clean-SC deconvolution method was used to improve the resolution of the acoustic sources, and integrated spectra were calculated for the individual blades. The sound sources were localized at the wind turbine blades and assigned to the leading edge and trailing edge subregions. The results show a high dependency on the sound source distribution and the source strength with regard to the observed one-third octave bands, wind velocity, and blade geometry. Hence, the localization of rotating sound sources with a microphone array is a suitable method for the development of wind turbine blades that emit less noise.
... The lifting wire ropes are very useful and used in several industrial sectors, such as aeronautical systems [1], civil engineering [2,3], lifting structures…Etc. They consist of 18 strands in helical from around a central core strand, each strand consists of a 7 wires of highresistance wires disposed in helical form around a strand core which may be a single wire or a group of wires [4]. ...
To ensure and guarantee the reliability of lifting structures and equipment, mechanics need effective control tools to
determine the condition and lifetime of these structures, this work is in this context, it is designed to estimate the reliability
and damage of the wire rope from the behavior of its components (wires, strand, layers) and to find an analytical model
which generalizes the behavior of the whole wire rope . It is also designed to establish the relationship between damage and
reliability in the case of compound systems.
... More than 70 % of the tests utilize this kind of multicomponent force and moment measure instrumentations to estimate aerodynamic loads [1]. With today's increasing requirements of aerodynamic experiments for aerospace vehicles, ground vehicles, modern and unique architectures, etc., customers are concerned much more about the performance of the wind tunnel force measurements [2]- [5]. Therefore, wind tunnel balance developing technology has been focused and promoted for more than 100 years to achieve higher accuracy of steady and fluctuating force measurements [6]- [9]. ...
... Minimizing the reciprocal of stiffness summation K(X) is the objective function as expressed in (2). The stiffness of some simple structures, such as cantilever beams with specific dimensions, can be calculated by the formulas and methods in Table 1. ...
The traditional wind tunnel strain balance design cycle is a manual iterative process. With the experience and intuition of the designer, one solution that meets the design requirements can be selected among a small number of design solutions. This paper introduces a novel software integration-based automatic balance design optimization system (ABDOS) and its implementation by integrating professional design knowledge and experience, stepwise optimization strategy, CAD-CAE software, self-developed scripts and tools. The proposed two-step optimization strategy includes the analytical design process (ADP) and the finite element method design process (FEDP). The built-in optimization algorithm drives the design variables change and searches for the optimal structure combination meeting the design objectives. The client-server based network architecture enables local lightweight design input, task management, and result output. The high-performance server combines all design resources to perform all the solution calculations. The development of more than 10 balances that have been completed and a case study show that this method and platform significantly reduce the time for design evaluation and design-analysis-redesign cycles, assisting designers to comprehensively evaluate and improve the performance of the balance.
... A sudden large change in the drag coefficient of the boundary layer region is found at the laminar-turbulent transition as a noticeable characteristic, Figure 12. It was first mentioned by Eiffel, according to Chanetz [189]. The following three characteristics found in the general boundary layer over the plate can also be valid over the boundary layer on an airfoil. ...
The usage of wind turbines as an alternative source of energy is increasing globally. The improvement of the performance of wind turbines can lower the cost of this type of energy and secure ongoing success. Various aspects can lead to improvements in performance. This study focuses on the computer-aided investigation of aerodynamic performance, which can be improved by optimization of the airfoil shape and its boundary layer. A focus is on the role of the laminar boundary layer on the blade airfoil in improving the aerodynamic performance of the wind turbine. The profile was optimized by means of a Genetic Algorithm (GA). After the optimization, the physical relationship between the laminar boundary layer and three-dimensional rotating augmentation of the wind turbine rotor was found by implementation of the 3D correction code. The Gliding Ratio (GR), transition points, boundary layer thickness, and friction coefficient distributions, which were calculated with the software XFOIL and RFOIL, show that the optimized airfoil has the shape with larger boundary layer and higher GR than the reference profile. The 3D-corrected polar data, calculated by Hansen’s correction law, were used for the calculation of the power production for two different wind turbines. It is to demonstrate that the optimized airfoil shape can influence the wind turbine to produce greatly increased power production. The optimized airfoil gives higher sensitivity on the 3D rotational effect, which makes the optimized one has higher torque and the constant thrust of the blade compared to the reference. The Coriolis force related to the three-dimensional rotation of the rotor generated radial momentum of the blade, which moved the separation bubble towards the tip, while the delayed transition point decreased the separation bubble formation. The optimized airfoil had smaller stall regions and fewer bubble occurrences than the reference airfoil. This is shown in the comparisons of the two-dimensional CFD flow simulation, which was performed with CFD OpenFoam for both airfoils. This study tries to close a knowledge gap in the area of laminar boundary layer considerations of the airfoils of the wind turbine blade. The knowledge gap existed, because the laminar layer in wind turbine and aeronautic applications was considered to be an unimportant and in reality, scarcely-existing region by most researchers and was therefore not emphasized in previous research. Furthermore, the investigations on the physical connection between the airfoil boundary layer and three-dimensional rotating augmentation of wind turbines can serve as a cornerstone for future research on improving the prediction accuracy in the aerodynamic design of wind turbine blades with three-dimensional rotation. The performance improvements of wind turbines given by the slight change of the airfoil curvature can be a great insight for effective aerodynamic improvement in further airfoil research. This airfoil optimization with a laminar boundary layer also demonstrates the connection between the airfoil and the holistic performance improvement of the wind turbine, including aerodynamics and structural stability at the same time.
