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Dissertations / Theses on the topic 'Car Aerodynamics'
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1
Standen, Paul. "Towed vehicle aerodynamics." Thesis, University of Bath, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311175.
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Penning, Pieter Paulus. "Experimental and computational investigation into race car aerodynamics." Diss., University of Pretoria, 1999. http://hdl.handle.net/2263/30482.
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In this study, experimental tests and Computational Fluid Dynamics are used to investigate the aerodynamic performance of two types of track-based racing cars. After the literature study, where automotive aerodynamics is discussed in very general terms, the air flow beneath a Formula One Grand Prix Racing Car is investigated. This is achieved by fitting the under-tray of a 30% scale model of the Parmalat Forti Ford FGO 1-95 with surface-static pressure ports and testing the model in a rolling-road wind tunnel. By varying a number of model parameters, it is found that the wheels significantly alter the pressure distribution under the floor of the racing car at positions away from the centre-line. It is shown that the front or rear wheel sets are independently sufficient to induce the flow changes. The addition of the other set then only produces milder and more local changes. The numerical part of the floor investigation is aimed at reproducing the centre-line flow pattern by solving the full Reynolds-Average Navier-Stokes equations over a two-dimensional curvilinear grid of the isolated floor. Two algorithms, Roe's flux-difference splitting method and the commercial package, STAR-CD which employs the SIMPLE algorithm and a two-equation turbulence model, are used to solve the governing equations. It is found that although the correct trends are observed when two different ride heights are simulated, absolute correlation is inadequate despite the use of experimentally-controlled boundary conditions. The simulations are however used to demonstrate the saturation in downforce with increasing vehicle speed. In order to improve numerical accuracy, a second study was launched where the effect of including the centre-line profile of the complete vehicle is investigated. To reduce the amount of detail a 1/12th scale model of a generic BMW Touring Car is used. Experimental data in the form of centre-line surface-static pressure coefficients are used for numerical correlation. The data is obtained by testing the three-dimensional model in a wind tunnel fitted with a stationary-road raised-platform floor. To establish continuity, the experimental data is used to show the similarities between the pressure distribution on the centre line of the open-wheel and the closed-wheel racing car. The effect of a rear-mounted aerodynamic device on the downforce is also discussed. The numerical investigation using the SIMPLE algorithm of STAR-CD and three high Reynolds-Number turbulence models, is based on the centre-line profile of the experimental model. It is seen that although qualitative correlation exists in areas around the car, quantitative agreement is less positive. Discrepancies are found to be most significant under the floor. It is shown that the influence of the three dimensional flow field on the experimental results are unlikely to cause satisfactory correlation. It is suggested that, in order to improve correlation, a new investigation is launched aimed at refining the numerical model. An outline for the new study is presented and includes simulations indicating the dependence of the computational solution on the density of the grid and on the user-definable turbulence parameters.Dissertation (M Eng (Mechanical Engineering))--University of Pretoria, 1999.
Mechanical and Aeronautical Engineering
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3
Fuller, Amanda Jane. "The aerodynamics of Formula One car cooling ducts." Thesis, University of Cambridge, 2004. https://www.repository.cam.ac.uk/handle/1810/265465.
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Formula One teams expend a large amount of effort optimising the aerodynamics of the exterior of the cars. However, there is comparatively little understanding of the mechanisms governing the flow through the sidepod ducts. These contain the heat exchang,ers for cooling the engine and gearbox. The aim of this thesis is to investigate features of the flow through the sidepod ducts, to provide a base of understanding from which further optimisation can be undertaken. When designing the sidepod ducts and the heat exchangers, the aim is to provide the required cooling rate, whilst minimising weight, centre of gravity and incurring the smallest possible aerodynamic penalty. An idealised lD model of the flow through a sidepod is presented and used to assess which geometric features have the largest effect on duct performance. A numerical investigation of the effect of a non-uniform flow distribution through a heat exchanger is also undertaken. Experiments are conducted to quantify the loss of stagnation pressure associated with inclining a radiator within a duct. Inclination loss is divided into incidence lo~s and loss due to the duct shaping immediately downstream of the radiator. An actuator-disc type model of the radiator performance is added to one of the in-house CFD codes. This modified code is used to carry out further investigation into the effects of shaping the downstream duct. A study of the use of metal or graphite foams in a Formula One heat exchanger is performed. It is shown that a foam radiator could only deliver comparable performance to the current louvered fin radiator if it had a much larger volume. It is recommended that no further investigative work is conducted into the use of such foam heat exchangers. The components of this investigation are drawn together to provide some design recommendations for the future optimisation of sidepod ducts. These include the shaping of the inlet duct in order to reduce incidence losses and the shaping of the downstream duct immediately adjacent to the heat exchangers in order to minimise any detrimental flow interactions.
4
Janda, Tomáš. "Karoserie sportovního automobilu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229888.
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Diedrichs, Ben. "Studies of Two Aerodynamic Effects on High-Speed Trains : Crosswind Stability and Discomforting Car Body Vibrations Inside Tunnels." Doctoral thesis, Stockholm : School of engineering sciences, Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4174.
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Popat, B. C. "Study of flow and noise generation from car A-pillars." Thesis, Imperial College London, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364782.
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Lyu, Zhipeng. "Aerodynamic Wind Tunnel in Passenger Car Application." Thesis, KTH, Mekanik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-203971.
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The thesis aims to provide an evaluation on the Volvo 1/5th scaled wind tunnel regarding its potentials and capabilities in aerodynamic study. The flow quality in the test section was evaluated. The experiments were performed included measurements of airspeed stability, tunnel-wall boundary layer profile and horizontal buoyancy. A numerical model was developed to predict the boundary layer thickness on the test floor. Repeatability tests were also conducted to establish the appropriate operating regime.A correlation study between the 1/5th scaled wind tunnel (MWT) and full scale wind tunnel (PVT) was performed using steady force and unsteady pressure measurements. The Volvo Aero 2020 concept car was selected to be the test model.The Reynolds effect and the tunnel-wall boundary layer interference were identified in the steady force measurements. Unsteady near-wake phenomena such as wake pumping and wake flapping were discussed in the unsteady base pressure measurements.
8
Jánošík, Tomáš. "Aerodynamická analýza prototypu létajícího automobilu Aircar 5.0." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400826.
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This thesis focuses on CFD analysis of the Aircar 5.0 flying car prototype. The theoretical part covers basic information about the connection between the aerodynamics of airplanes and cars as well as cars themselves. The computational part begins with the calibration of the mathematical model, continues with the CFD simulations, which have the role to determine basic aerodynamic characteristics of the Aircar in vehicle mode. There are several configurations tested to find out their influence on aerodynamic stability and their advantages and disadvantages are summed up in the conclusion chapter.
9
Morgan, Claire Elizabeth. "Unsteady vortex interactions related to a Formula One car front wing and wheel." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.608608.
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Henni, Mansour Zoubir. "Optimisation des formes de voitures de tourisme de petites dimensions par le critère de bombement de surfaces et le couplage des arêtes par la méthode des angles privilégiés." Valenciennes, 1996. https://ged.uphf.fr/nuxeo/site/esupversions/e10c7e64-0b83-4cdd-af36-c2de4c3e45ec.
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A partir de la mise en relief de l'isomorphisme entre les deux structures fondamentales micro et macroscopique, respectivement dans l'atome d'hydrogène et dans l'hélium liquide superfluide, par l'existence d'une discrétisation d'angles, entre deux directions de rotation ou de champ magnétique auxquels le professeur M. Le ray et ses collaborateurs ont donné le nom d'angles privilégiés, il a été mis en évidence que cette discrétisation d'angles est présente universellement dans la nature, l'art, l'architecture et les écoulements fluides en particulier (aéro et hydrodynamique). Depuis lors, de nombreuses recherches ont été menées dans notre laboratoire sur des ailes delta, double delta, ailes ogivales, cônes et autres corps élancés présentant ou non des angles privilégiés. Les résultats concernant les positions relatives privilégiées de tourbillons obtenus sont très nombreux et inédits et présentent un intérêt majeur notamment dans la correction, voire la suppression de l'instabilité, et de l'élargissement des tourbillons à l'extrados de ces ailes. Au cours de ces dernières années, et parallèlement aux études faites sur des ailes, des recherches ont été menées dans notre laboratoire, sur des maquettes de voitures de différentes dimensions. Les résultats fort intéressants ont montré l'importance relative des angles privilégiés notamment en ce qui concerne la réduction du coefficient de trainée Cx, la stabilité et l'organisation de l'écoulement autour de ces maquettes ; entrainant par la suite une consommation réduite du carburant, une meilleure stabilité et une meilleure tenue de route. En effet, les expériences effectuées lors de ce présent travail avec 9 maquettes de voitures de petites dimensions, donnent un ensemble de résultats qui confirment l'intérêt des formes de carrosseries construites en utilisant très largement la notion d'angles privilégiés. On observe que de nombreuses de ces formes bénéficient d'un écoulement aussi exempte que possible de décollement. Le sillage à l'arrière de la carrosserie est stable et aussi peu divergent que possible, ce qui conduit à une valeur réduite du Cx. Par contre, les formes ne possédant pas des angles privilégiés conduisent à des décollements qui sont sources de dissipation de l'énergie, entrainant l'instabilité du véhicule et la surconsommation du carburant. En plus de ces améliorations techniques, on peut noter également un second point très important, qui est caractérisé par l'élégance et la beauté du style du véhicule.
11
Daniel, Petr. "Analýza vlivu polohy karoserie závodního vozu na aerodynamické charakteristiky." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230353.
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Master’s thesis deals with the aerodynamics of racing vehicle for various settings of clearance and tilt of body. First is described the theory of aerodynamics and flow. It was necessary to build the CAD model of racing car for analysis. Assembly of this model is the next chapter of the master’s thesis. This is followed by CFD analysis, where is displayed a simplified model of the vehicle. This part describes the overall process and setting in the CFD program. In conclusion, the results are summarized for each setting.
12
Soso, Michael D. "An investigation into the aerodynamics of a wing in ground effect in generic racing car wake flows." Thesis, University of Southampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.417986.
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Peichl, Martin Alexander [Verfasser], Thomas [Akademischer Betreuer] Indinger, Thomas [Gutachter] Indinger, and Makoto [Gutachter] Tsubokura. "Investigation of Coherent Structures in Unsteady Car Aerodynamics / Martin Alexander Peichl ; Gutachter: Thomas Indinger, Makoto Tsubokura ; Betreuer: Thomas Indinger." München : Universitätsbibliothek der TU München, 2019. http://d-nb.info/1200547578/34.
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Čavoj, Ondřej. "Výpočet aerodynamických charakteristik vozidla s vybočením." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230267.
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This Diploma thesis deals with CFD simulations of flow around vehicles subjected to a crosswind with MIRA Reference Car in three body shapes with a diffuser serving as a vehicle. It contains tuning of computational grid and chosen solver settings in Fluent, mostly for v2f turbulence model. The main output of this thesis is a simulation of all body shapes in several crosswind angles in steady state and one chosen body shape with one chosen crosswind angle in unsteady state. All results are validated against measurements taken with full scale models in MIRA windtunnel.
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Melchiorre, Simone. "Delayed Detached Eddy Simulation of the exhaust system of a LMP2 car." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
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Talking about race cars' aerodynamics, effects that the exhaust system has on the latter can not be ignored. In the past years, engineers take advantage of these high-energy flows which have turned to be the key point in many car competitions.
The purpose of this thesis is to identify a methodology for the fluid dynamic simulation of the exhaust gases, in cross-flow configuration, aimed to predict the effect on the car's aerodynamic load through the application of Delayed Detached Eddy Simulations (DDES). Furthermore, it wants to evaluate the differences, in terms of loads and fluid structures, between this model and the Reynolds-averaged Navier–Stokes Eddy Viscosity Model (RANS-EVM). The car considered for the study is the Dallara P217 built by Dallara to compete in the 2017 World Endurance Championship (WEC). The basic hypothesis in DDES modelling is the linearization of the vehicle-exhaust system. The flows inside the exhaust pipes (Sub-Model Simulation) and the external flows outside the car (Full-Model Simulation) were therefore independently simulated. The Full-Model simulation models the exhaust flows through the use of a velocity inlet condition; the data necessary for the definition of this boundary condition are the results coming from the Sub-Model simulation.
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Bork, Carrington E. "Aerodynamic Development of the Buckeye Bullet 3 Electric Landspeed Vehicle." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1339688241.
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Littlewood, Rob. "Novel methods of drag reduction for squareback road vehicles." Thesis, Loughborough University, 2013. https://dspace.lboro.ac.uk/2134/12534.
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Road vehicles are still largely a consumer product and as such the styling of a vehicle becomes a significant factor in how commercially successful a vehicle will become. The influence of styling combined with the numerous other factors to consider in a vehicle development programme means that the optimum aerodynamic package is not possible in real world applications. Aerodynamicists are continually looking for more discrete and innovative ways to reduce the drag of a vehicle. The current thesis adds to this work by investigating the influence of active flow control devices on the aerodynamic drag of square back style road vehicles. A number of different types of flow control are reviewed and the performance of synthetic jets and pulsed jets are investigated on a simple 2D cylinder flow case experimentally. A simplified ¼ scale vehicle model is equipped with active flow control actuators and their effects on the body drag investigated. The influence of the global wake size and the smaller scale in-wake structures on vehicle drag is investigated and discussed. Modification of a large vortex structure in the lower half of the wake is found to be a dominant mechanism by which model base pressure can be influenced. The total gains in power available are calculated and the potential for incorporating active flow control devices in current road vehicles is reviewed. Due to practicality limitations the active flow control devices are currently ruled out for implementation on a road vehicle. The knowledge gained about the vehicle model wake flow topology is later used to create drag reductions using a simple and discrete passive device. The passive modifications act to support claims made about the influence of in wake structures on the global base pressures and vehicle drag. The devices are also tested at full scale where modifications to the vehicle body forces were also observed.
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Stiborová, Dana. "Aktivní aerodynamické prvky osobních vozidel." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318777.
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In this diploma thesis active aerodynamic components are designed, specifically brake cooling duct and active automotive wing. Cooling duct prototype and also active regulation controlling electronics including the software were created. Road test was performed to measure the duct parameters. Construction design and the active regulation function of the automotive wing were created. The influence of the wing on aerodynamic characteristics of the car was determined.
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Akcali, Fikri. "Experimental Investigation Of Flow Separation From Rigid Walls With Salient Edges." Master's thesis, METU, 2004. http://etd.lib.metu.edu/upload/1097971/index.pdf.
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This thesis presents the experimental results on the formation of flow separation from a rigid wall with a salient edge. In the case of automotive vehicles or aircrafts with rear cargo compartment doors, such salient edges are at the origin of separated wake flows resulting in increased drag and other disturbing effects. Recent studies of Ahmed et al. (1984) on simplified geometries showed the strong influence of the slant angle on the flow separations. In this study, the geometry is further simplified to examine the flow separation under two-dimensional conditions. The experimental configuration consists
of a fixed horizontal front panel and an attached rear panel with variable slant angle. The experiments were carried out in a low speed water channel to analyze the flow structure by flow visualization techniques. The hydrogen bubble technique nd PIV measurements are used to obtain both qualitative and quantitative information on the flow structure. The electrolytic precipitation technique is used to analyze the flow separation in more detail. The slant angle varied between 0 and 35 degrees while the Reynolds numbers of the model was fixed to 24800 and 50500. As a function of slant angle and Reynolds number, two different types of flow separation were observed: boundary layer separation due to adverse pressure gradient and the so called &ldquoinertial separation&rdquo
at the edge singularity. Future strategies to control the formation of the wake flow highly depend on the very different flow structure of these two types of separation.
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Croner, Emma. "Etude de l'écoulement autour des ensembles roulants d'un véhicule en vue de l'optimisation aérodynamique du pneumatique." Thesis, Toulouse, ISAE, 2014. http://www.theses.fr/2014ESAE0008/document.
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Cette thèse, collaboration entre Michelin et l’ONERA, propose de mettre en œuvre des simulations instationnaires URANS grâce au code Navier-Stokes elsA de l’ONERA en vue d’analyser l’écoulement complexe 3D instationnaire se développant au voisinage des roues d'un véhicule et d’identifier les mécanismes à l’origine de la production de traînée.En effet, les roues (jantes et pneumatiques) constituent un nouvel axe de recherche prometteur en aérodynamique automobile car on estime de 20% à 40% la contribution des roues et passages de roues à la traînée totale. Cependant, leur optimisation nécessite en premier lieu une compréhension complète des phénomènes aérodynamiques mis en jeu. Les analyses spatio-temporelles menées sur roue isolée et sur véhicule pour trois types de pneumatiques (lisse, rugueux, avec sillons) apportent de nouveaux éléments de compréhension sur la physique de l’écoulement. Ce travail répond notamment aux limites principales des études précédentes grâce à la description de l'écoulement sur des géométries de référence incluant des pneumatiques déformés lisses et grâce à l’étude de l’instationnarité. Les analyses spatiales permettent de décrire l’organisation des structures tourbillonnaires sur roue isolée puis autour des roues avant et arrière d’un véhicule simplifié. Les analyses temporelles facilitent quant à elles la compréhension de la dynamique de l’écoulement par la mise en évidence de la génération des tourbillons et des mécanismes d’interaction avec la carrosserie. Des validations expérimentales sont effectuées à la fois sur roue isolée et sur véhicule en soufflerie. Enfin, l’utilisation de plusieurs types de pneumatiques démontre leur capacité à modifier les caractéristiques spatio-temporelles de l’ensemble de l’écoulement et à jouer ainsi sur la puissance dissipée par le véhicule via la traînée et le moment de rotation des rouesAs a collaborative task between Michelin and ONERA, this thesis aims to investigate the complex unsteady 3D flow around car wheels and to identify the mechanisms of drag production linked to this part of the car thanks to URANS unsteady numerical simulations using ONERA’s Navier-Stokes code elsA. The wheels (i.e. rims and tyres) are indeed a promising research topic in the field of car aerodynamics. The part of the total drag due to the wheels and wheelhouses is indeed estimated between 20% and 40%. The first step towards wheel optimisation is to achieve full understanding of the aerodynamic phenomena produced around them. The analysis of the flow for three types of tyres (smooth, rough, grooved), both around isolated wheels and around a simplified vehicle, brings further understanding of the flow physics. This work completes previous studies in this field thanks to the description of basic flows around smooth wheels and the study of unsteady effects. It describes the arrangement of vortical structures around an isolated wheel and around the front and rear wheels of a simplified vehicle. Moreover, the analysis of the flow unsteadiness facilitates understanding of the flow dynamics by highlighting the generation of the main vortices and the interaction phenomena with the car body. The validation of numerical models is performed with specific experiments by Michelin on both an isolated wheel and a vehicle configuration. Finally, the use of different tyres shows their ability to modify both space and time characteristics of the whole flow, thus modifying the power dissipated by the car drag and the rotation moment of the wheels
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de, Fluiter Travis. "Design of lightweigh electric vehicles." The University of Waikato, 2008. http://hdl.handle.net/10289/2438.
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The design and manufacture of lightweight electric vehicles is becoming increasingly important with the rising cost of petrol, and the effects emissions from petrol powered vehicles are having on our environment. The University of Waikato and HybridAuto's Ultracommuter electric vehicle was designed, manufactured, and tested. The vehicle has been driven over 1800km with only a small reliability issue, indicating that the Ultracommuter was well designed and could potentially be manufactured as a solution to ongoing transportation issues. The use of titanium aluminide components in the automotive industry was researched. While it only has half the density of alloy steel, titanium aluminides have the same strength and stiffness as steel, along with good corrosion resistance, making them suitable as a lightweight replacement for steel components. Automotive applications identified that could benefit from the use of TiAl include brake callipers, brake rotors and electric motor components.
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Dahlberg, Henrik. "Aerodynamic development of Formula Student race car." Thesis, KTH, Mekanik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-148799.
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This thesis describes the process of developing the aerodynamics package of a Formula Student race car with computational uid dynamics. It investigates the eects of aerodynamics on the vehicle's behaviour and performance with regard to the Formula Student competition format. The methods used during the development are evaluated and put into context by investigating the correlation between a wind-tunnel experiment of a wing in ground proximity, and its simulated counterpart. The aerodynamics package consists of an undertray, a front wing and a rear wing and the report details the stages involved in optimising these components to achieve the desired results.Denna avhandling beskriver processen att utveckla ett aerodynamikpaket för en Formula Student-bil med strömningsmekaniska beräkningar. Den unders öker eekterna av aerodynamik på fordonets beteende och prestanda med avseende på tävlingsformatet. De metoder som används under utvecklingen utvärderas och sätts i sitt sammanhang genom att undersöka hur väl ett vindtunnelexperiment av en vinge nära marken korrelerar med dess simulerade motsvarighet. Aerodynamikpaketet består av ett golv, en främre vinge och en bakre vinge och rapporten detaljerar de steg som är involverade i att optimera dessa komponenter för att uppnå önskat resultat.
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Campbell, John A. "FORTRAN programs for aerodynamic analyses on the MicroVAX/2000 CAD/CAE workstation." Thesis, Monterey, California. Naval Postgraduate School, 1988. http://hdl.handle.net/10945/23241.
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Mears, Andrew Paul. "The aerodynamic characteristics of an exposed racing car wheel." Thesis, Durham University, 2004. http://etheses.dur.ac.uk/3124/.
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The aerodynamics of an exposed racing car wheel have been analysed using experimental and computational (CFD) techniques. A 40% full-scale pneumatic tyre/wheel assembly was used for the experimental investigations and the exact geometry was replicated in the CFD model. The wheel had an aspect ratio of 0.53 and the tests were conducted at a Reynolds number, based on the wheel diameter, of 2.5 x 10 . Both rotating and stationary wheels were tested with moving and fixed ground-planes, respectively. The experiments were conducted using new and existing methods of data acquisition and analysis. A non-intrusive radio telemetry system was successfully designed and developed that enabled surface static pressure data to be transmitted from a rotating wheel to a local PC. Other experimental techniques included the use of particle image velocimetry (PIV) and a pneumatic non-embedded five-hole pressure probe to investigate the flow-field about the wheel. The early flow separation, which is a characteristic of the rotating wheel, was observed in the surface static pressure distributions and PIV velocity fields. Lift and drag forces were found to decrease as a result of wheel rotation, which agreed with the work of other investigators, and the mechanisms responsible for such force reductions are postulated. The wake structures were investigated and showed weaker streamwise vorticity for the rotating wheel compared to the stationary wheel. The most important and remarkable aspect of this work was the experimental observation and subsequent CFD prediction of the rear jetting flow mechanism whose existence was previously theoretically predicted by another investigator. The PIV velocity fields clearly show the rear jetting phenomenon and this is further corroborated by a negative pressure peak in the surface pressure distributions on the wheel centreline. The effects the rear jetting phenomenon has on the wake mechanics, and hence the forces acting on the rotating wheel, are postulated.
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Boudali, Selma, and Mattias Olausson. "Venturi Undertray : KTH Bachelor Thesis Report." Thesis, KTH, Skolan för industriell teknik och management (ITM), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-274378.
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This bachelor thesis aims to describe the work performed for the design of the undertray for the Kungliga Tekniska Högskolan Formula Student(KTHFS) race car. The goal was to achieve an aerodynamically optimized undertray design that follows the regulations of the competition and the targets set by KTHFS concerning the weight, the size, the materials needed for its manufacture and costs. After some research on previous work, the concept, on which we decided that the undertray would rely on, is Venturi tunnels inspired by the Aston Martin Valkyrie, chosen for its ability to provide a large amount of downforce with a negligible amount of drag using ”ground effect”. Numerous CAD design models were created in Solid Edge and a finalized design was then ported over to Siemens NX to be analyzed using Star-CCM+ and its Design Manager feature. The CFD analyses and optimization was performed in Star-CCM+ with regards to pressure gradient, streamline velocity and downforce. These were done with variable parameters in areas such as expansion height, inlet area and ride height. Contained within this report is a more detailed description of how the CFD analysis was performed as well as suggestions for manufacturing said undertray. Given the time constraints and the societal impacts of COVID-19, manufacturing had to be removed from the scope of the project, however, a step-by-step manufacture guide is provided within. Analysis of uur final design showed 428 N of downforce, a weight of 2.55 kg and a production cost of approximately 2320 SEK. It therefore passes the requirements for weight, cost and ride-height rule regulations set by Formula Student and internal KTHFS targets.Detta kandidatexamesarbete syftar till att beskriva arbetet som utförts för konstruktionsdesignen av Kungliga Tekniska Högskolan Formula Student (KTHFS) racerbils underrede. Målet var att uppnå en aerodynamisk optimerad underredes design som följer de regler och krav fastställda av KTHFS gällande vikt, storlek, material som behövs till tillverkningen och kostnader. Efter en litteraturstudie på tidigare arbete, blev Venturi tunnlar, inspirerade av Aston Martin Valkyrie, konceptet som vi beslutade att uderreden skulle bygga på och valda på grund av deras förmåga att förbättra bilens prestanda genom sitt nedkraftsbildande och försumbar mängd drag med hjälp av ”ground effect”. Många CAD-designmodeller skapades i Solid Edge och en slutgiltig design överfördes sedan till Siemens NX för att analyseras med Star CCM+ och dess Design Managerfunktion. CFD-analyserna och optimeringen utfördes i Star CCM+ med avseende på tryckgradient, strömlinjehastighet och nedkrafter. Dessa gjordes med variabla parametrar i områden som utvidgningshöjd, inloppsarea och frigångshöjd. I denna rapport finns en mer detaljerad beskrivning av hur CFD-analysen utfördes samt förslag för tillverkning. Med tanke på tidsbegränsningarna och samhällseffekterna av COVID-19 fick vi ta bort tillverknink från projektets omfattning, men en steg-för-steg tillverkningsguide tillhandahålls i rapporten. Analyser av vår slutgiltiga design visade på 428N downforce, en vikt på 2,55 kg och en produktionskostnad på cirka 2320 SEK. Den överenstämmer därför kraven för vikt, kostnad och frigångshöjd som fastställdes av Formula Student.
26
Marshall, David William. "Experimental investigations into the aerodynamic development relevant to a world rally car." Thesis, University of Southampton, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.543401.
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Newbon, Joshua James. "Aerodynamic effects of the salient flow features in Grand Prix car wakes." Thesis, Durham University, 2017. http://etheses.dur.ac.uk/12051/.
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Grand Prix cars are the fastest circuit racing cars in production, a large part of this is due to the high downforce generated by the car's aerodynamic surfaces, in excess of the car's own weight above 150kph. It is well known that a race-car operating in the wake of an upstream vehicle experiences a reduction of aerodynamic drag, and a corresponding increase of ultimate straight line speed. There is also a loss of aerodynamic downforce, predominately from surfaces acting on the front axle. The effect of the reduced downforce is an increase of lap-time and degraded handling characteristics, thereby reducing tyre life and the ability to follow the lead car or affect an overtake. The wake of a generic Formula 1 car is shown to be characterized by a counter-rotating vortex pair, with centreline up-wash and a region of total pressure deficit, which is predominately a dynamic pressure deficit, with Cpo < 0. The streamwise vorticity is dominated by the tip vortex pair emanating from the rear wing, which merges with other vortices, forming a coherent structure by just half a car length behind the rear of the car. The vortices have an influence on the location and strength of the total pressure deficit, sweeping the loss to the centreline, and upwards to surround the vortex cores, forming a 'mushroom' shaped wake. The effect of an upstream vehicle wake has been measured in the wind tunnel and computationally, with downforce and drag losses of up to 67% and 29% respectively. The use of a short axial length bluff-bodied wake generator allows for a longer axial separation to be achieved with a complete downstream vehicle, in a conventional length wind tunnel working section, without further compromising the downstream model scale. The sensitivity of the downstream car to the various salient flow features in the upstream wake have been investigated using the method of imposing the wake on the inlet of a CFD simulation. Imposing the wake has meant that the wake can be altered without the need to modify the upstream vehicle surfaces. The key wake feature has been shown to be the axial velocity deficit, which accounts for up to 90% of the downforce loss experienced by the following vehicle. While secondary flows in the wake do result in downforce loss for the following vehicle, they are also beneficial in diverting the dynamic pressure deficit over the following vehicle, thereby introducing higher energy flow onto the following vehicle.
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Strachan, Russell K. "The aerodynamic interference effects of side wall proximity on a generic car model." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/4643.
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The flow around a generic car model both in isolation and in proximity to a near side wall has been investigated utilising experimental and computational methods. Phase one of this investigation tested a range of Ahmed generic road vehicle models with varying backlight angles in isolation, employing laser-Doppler anemometry, static pressure and aerodynamic force and moment measurements in the experimental section. Additionally, numerical simulations were conducted using a commercial Reynolds-averaged Navier Stokes (RANS) code with the RNG k-ε turbulence model. This phase served both to extend the previous knowledge of the flow around the Ahmed model, and analyse the effects of both the supporting strut and rolling road. Phase two then used similar methods to investigate the Ahmed model in proximity to a non-moving side wall. Results from phase two are compared with previous near-wall studies in order that an understanding of the effects of wall proximity can be presented, an area lacking in the existing literature. It is found that the flow on the isolated model must be understood before the effects of side wall proximity can be assessed. There is though, in general, a breakdown of any longitudinal vortices on the near-wall side of the model as model-to-wall distance reduces, with an increase in longitudinal vortex strength on the model side away from the wall. There also exists a large pressure drop on the near-wall model side, which increases in magnitude as model-to-wall distance reduces, before dissipating at separations where the boundary layer restricts the flow. Additionally, there is found to be a pressure drop on the top and bottom of the model with decreasing wall distance, with the relative magnitudes of these dependent on model geometry.
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Strachan, R. K. "The aerodynamic interference effects of side walll proximity on a generic car model." Thesis, Department of Aerospace, Power & Sensors, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/4643.
Full textAbstract:
The flow around a generic car model both in isolation and in proximity to a near side wall has
been investigated utilising experimental and computational methods.
Phase one of this investigation tested a range of Ahmed generic road vehicle models with
varying backlight angles in isolation, employing laser-Doppler anemometry, static pressure
and aerodynamic force and moment measurements in the experimental section. Additionally,
numerical simulations were conducted using a commercial Reynolds-averaged Navier Stokes
(RANS) code with the RNG k-ε turbulence model. This phase served both to extend the
previous knowledge of the flow around the Ahmed model, and analyse the effects of both the
supporting strut and rolling road. Phase two then used similar methods to investigate the
Ahmed model in proximity to a non-moving side wall.
Results from phase two are compared with previous near-wall studies in order that an
understanding of the effects of wall proximity can be presented, an area lacking in the existing
literature.
It is found that the flow on the isolated model must be understood before the effects of side
wall proximity can be assessed. There is though, in general, a breakdown of any longitudinal
vortices on the near-wall side of the model as model-to-wall distance reduces, with an
increase in longitudinal vortex strength on the model side away from the wall. There also
exists a large pressure drop on the near-wall model side, which increases in magnitude as
model-to-wall distance reduces, before dissipating at separations where the boundary layer
restricts the flow.
Additionally, there is found to be a pressure drop on the top and bottom of the model with
decreasing wall distance, with the relative magnitudes of these dependent on model
geometry.
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Vobejda, Radek. "Výpočtové modelování aerodynamického hluku způsobeného bočním zrcátkem automobilu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-401556.
Full textAbstract:
The master’sthesis deals with numerical modelling of aerodynamic noisewhich arisesinside of the carcabin. In the first part ofthe thesis simplified model of geometry of the car and of the inside acoustic pressure arecreated. After that numerical analysis of created models of geometry are doneandvarious models of turbulenceare discussed. The results of these CFD simulationswhere then used for changing the model of geometry of the wing mirror. Outputs of these simulations were used for solving the numerical analysis of noise in the car cabin.
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Kumar, Manish. "Application of frequency-domain-method to rotorcraft aerodynamics." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2008. http://wwwlib.umi.com/cr/syr/main.
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Lien, Morten Stenstad. "Aerodynamic Development and Construction of a Car for Participation in the Eco-Marathon Competition." Thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10809.
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The authors of this paper were responsible for aerodynamic development of, as well as assisting in the production of components for, the NTNU vehicle for the Shell Eco-marathon competition, DNV Fuel Fighter. A drag reducing end extension, with the intent of delaying flow separation, was designed, produced and mounted on the vehicle. Due to wind tunnel breakdown the final product could not be tested, but the prototype was measured to give a drag reduction of between 8% and 15% for 0 to 15 degrees yaw angle. During the competition the team did not complete an approved run due to technical difficulties with the propulsion and the electronic control system.
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Eikeland, Henrik Aaserud. "Aerodynamic Development and Construction of a Car for Participation in the Eco-Marathon Competition." Thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-10810.
Full textAbstract:
The authors of this paper were responsible for aerodynamic development of, as well as assisting in the production of components for, the NTNU vehicle for the Shell Eco-marathon competition, DNV Fuel Fighter. A drag reducing end extension, with the intent of delaying flow separation, was designed, produced and mounted on the vehicle. Due to wind tunnel breakdown the final product could not be tested, but the prototype was measured to give a drag reduction of between 8% and 15% for 0 to 15 degrees yaw angle. During the competition the team did not complete an approved run due to technical difficulties with the propulsion and the electronic control system.
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Kubíček, Martin. "Aerodynamická optimalizace karoserie automobilu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229322.
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The diploma thesis is focused on create an optimization methodology for CFD issues or any other computationally demanding software. Optimization method is applied on simplified model of car, where improves its aerodynamic properties
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Ghadiani, Ali. "Aerodynamics and aeroacoustic of sail masts." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
Find full textAbstract:
In this thesis, the turbulent flow induced by sail masts is simulated using compressible k-w SST detached eddy simulation (DES). The mast is investigated in two different yaw angles at 0 and 90 and the predetermined condition is V = 20 m/s to find the main broadband and tonal noise sources. And then the same cases are compared to simple shape of sail mast without internal cavities. The purpose of this work is to investigate whether the cases generate tonal noise when winds past the sail mast. Another objective is to study aerodynamic parameters around the four cases. The influence of the mast tips is assessed and the Sound Pressure Levels (SPL) that are gotten from pressure fluctuations are shown at the end to find the tonal noise and show the study cases with a cavity inside make much more noise than simplified sail mast. By looking at the peaks in the sound pressure level (SPL) the tonal noise at specific frequencies can be found.
The commercial software STAR-CCM+ was used for all three parts pre-processing, running simulations, and post-processing to understand the noise generation and aerodynamic features.
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Ahsan, Mahim. "Numerical Study on Aerodynamic Drag Reduction on a Rear Wing of a Formula Student Car." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-297496.
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The importance of aerodynamics in racing has increased substantially over the past decades. Racing vehicles utilize different aerodynamic devices, to redirect the airflow around the vehicle in a beneficial way. The increase in downforce using an aerodynamic wing package increases drag force. The drag force limits the top speed and the maximum acceleration of the vehicle and is an unwanted effect of increased downforce. To combat this, top-performance vehicles utilize a drag reduction system (DRS). The DRS is an active system of the vehicle, which allows adjustment of the angle of attack (AoA) of wings on the vehicle while driving on track when deemed beneficial. This thesis will investigate the possibility of adding a DRS to the rear wing of a Formula Student vehicle. All tests were done by simulations, no physical tests were done in this thesis. The investigation of a DRS was done in three stages. The first step was to create a 3-dimensional CAD-model that complied with the Formula Student Germany rules. The design of the rear wing was based on the current rear wing on the KTH Formula Student vehicle. The current rear wing was slightly redesigned for this project to facilitate the investigation of a DRS. The second step was to create a mesh model. A mesh is a representation of a geometry, it defines the physical shape of an object, in this case the rear wing. The more detailed a mesh is, with a higher number of cells, the more accurate the results will be from the simulations. However, a finer mesh with a high number of cells increases the simulation time significantly. Therefore, it is important to find a good balance between the number of cells and the time it takes to make a simulation. After a mesh was generated, physics models for the simulation were determined. The final step was to make simulations based on the physics models chosen. For this project, Siemens NX was used to design a three-dimensional model of the wing and Siemens STAR-CCM+ was used to make the simulations and meshes. The resulting reduction in drag was calculated to 78 per cent between the closed configuration and the open configuration with the least drag. However, there is a large amount of separation between the airflow and the rear wing on all configurations simulated except at the AoA -10°. When the airflow separates downforce decreases and drag increases and is not desirable. The drag on the rear wing can be decreased by utilizing a DRS as observed from the results. The drag reduced by the DRS at 15° and -10° AoA and a DRS would certainly be beneficial. Further investigation of computational fluid dynamics and aerodynamics is recommended to complement the result. There are uncertainties in the results due to inadequacy in the mesh and design of the rear wing. By addressing these uncertainties better results can be achieved.
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Sarimurat, Mehmet Nasir. "Analytical models for flow control in subsonic and supersonic diffusing flow paths using steady blowing and suction." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2008. http://wwwlib.umi.com/cr/syr/main.
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Li, Ruiying. "Aerodynamic Drag Reduction of a Square-Back Car Model Using Linear Genetic Programming and Physic-Based Control." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2017. http://www.theses.fr/2017ESMA0014/document.
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Le but de la thèse est de développer des stratégies de contrôle efficaces pour la réduction de la trainée aérodynamique des véhicules terrestres. Nous examinons expérimentalement les effets d’un forçage fluidique sur le sillage d’un modèle de véhicule simplifié à culot droit. Le forçage est effectué par des jets pulsés aux arêtes et16 capteurs de pression répartis à la surface arrière permettent d’estimer la traînée instantanée. Nous abordons le problème difficile du contrôle de l’écoulement turbulent non linéaire---qui est souvent au-delà des capacités de la modélisation réduite---par le développement d'une stratégie de contrôle sans modèle: le contrôle via la programmation génétique linéaire (LGPC) dirigé par les données. Cette méthode explore et exploite la dynamique fortement non linéaire d'une manière non supervisée avec pas ou peu de connaissances antérieures sur le système.Le problème est de trouver une logique de contrôle qui optimise une fonction de coût donnée. Cette optimisation est réalisée par la programmation génétique linéaire comme un solveur de régression simple dans un espace de recherche de grande dimension. En particulier, cette recherche fait progresser et généralise les études antérieures sur le contrôle via la programmation génétique en incluant le forçage multi-fréquences, le signal des capteurs,l’historique des informations temporelles et leurs combinaisons dans l'espace de recherche de contrôle. La performance de LGPC est démontrée avec succès sur les expériences de contrôle de traînée du modèle de véhicule simplifié où le sillage turbulent présente une symétrie latérale et une asymétrie normale à la paroi. Environ 33% de récupération de pression au culot associée à 22% de réduction de trainée est obtenue dans toutes les classes de loisde contrôle considérées. L'énergie consommée du forçage ne représente que 30% de l'énergie aérodynamique récupérée. Dans ce travail, nous étudions également les sillages turbulents ayant une asymétrie latérale: un sillage intermittent et bi-modal à dérapage nul et un sillage asymétrique avec un angle de dérapage modéré de 5 degrés.Pour le sillage intermittent, un contrôle de rétroaction en opposition basé sur la physique est déduit à partir des essais précédents de contrôle en boucle ouverte. Le contrôleur supprime avec succès la bi-modalité du sillage et rend le sillage symétrique avec une réduction de traînée concomitante. Pour le sillage asymétrique en dérapage,nous construisons un contrôle bi-fréquence à l’arête au vent à partir des résultats de forçage à fréquence unique. Ce forçage bi-fréquentiel comprend deux fréquences ayant une différence d'un ordre de grandeur. Il combine les effets favorables de la vectorisation du sillage et le contrôle de l'équilibre des couches de cisaillement. Il est important de noter que la stratégie LGPC est également appliqué à cette situation en dérapage et converge vers le même forçage bi-fréquentiel. Les stratégies de contrôle proposées dans cette étude ouvrent de nouveaux chemins prometteurs pour le contrôle de la réduction de la traînée dans des conditions plus complexes de vitesse amont variable ou de rafaleThe thesis aims to develop effective active flow control strategies for aerodynamic drag reduction of road vehicles.We experimentally examine the effects of fluidic actuation on the wake past a simplified square-back car model.The actuation is performed with pulsed jets at trailing edges and the flow is monitored with 16 pressure sensors distributed at the rear side. We address the challenging nonlinear turbulence control---which is often beyond the capabilities of model-oriented approach---by developing a simple yet powerful model-free control strategy: the data-driven linear genetic programming control (LGPC). This method explores and exploits strongly nonlinear dynamics in an unsupervised manner with no or little prior knowledge about the system. The control problem is to find a control logic which optimizes a given cost function by employing linear genetic programming as an easy and simple regression solver in a high-dimensional control search space. In particular, the present work advances and generalizes the previous studies of genetic programming control by comprising multi-frequency forcing, sensor-based feedback including also time-history information feedback and combinations thereof in the control search space. The performance of LGPC is successfully demonstrated on the drag control experiments of the car model where the investigated turbulent wake exhibits a spanwise symmetry and a wall-normal asymmetry. Approximately 33% base pressure recovery associated with 22% drag reduction is achieved in all considered classes of control laws. The consumed actuation energy accounts for only 30% of the aerodynamic power saving. In this research, we also study the turbulent wakes having a lateral asymmetry: an intermittent bi-modal wake at zero yaw and an asymmetric wake at a moderate yaw angle of 5 degree. For the bimodal wake exhibiting are flectional symmetry-breaking, a physics-based opposition feedback control is inferred from the previous open loop control tests. The controller successfully suppresses the bi-modality of the wake and renders a symmetrized wake with a concomitant drag reduction. For the asymmetric wake at yaw, we infer from the single-frequency forcing results a bi-frequency control at the windward edge comprising two frequencies having one order of magnitude difference. This bi-frequency actuation combines the favorable effects of fluidic boat-tailing and balance control of the shear layers. Importantly, LGPC is also applied to this yawed situation and converges to the same bi-frequency actuation. The control strategies proposed in the present study open promising new paths for the control of drag reduction in more complex conditions such as the varying oncoming velocity and wind gust
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Wieser, Dirk [Verfasser], Christian Oliver [Gutachter] Paschereit, and Carsten [Gutachter] Repmann. "Experimental analyses of aerodynamic behaviour of DrivAer car model / Dirk Wieser ; Gutachter: Christian Oliver Paschereit, Carsten Repmann." Berlin : Technische Universität Berlin, 2021. http://d-nb.info/1238142311/34.
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Trujillo, Steven Mathew. "An investigation of the effects of spanwise wall oscillation on the structure of a turbulent boundary layer /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Thompson, Peter Mark. "Computation of CAD-based design velocities for aerodynamic design optimisation with adjoint CFD data." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.675476.
Full textAbstract:
This thesis describes the investigation and development of a novel CAD-based aerodynamic optimisation system, with the aim of allowing gradient-based optimisation of feature-based, parametric models within commercial CAD packages in timescales acceptable for industrial design processes. The process developed is based on linking parametric design velocities (geometric sensitivities computed from the CAD model representing the displacement of a point on the model boundary due to a perturbation of a CAD model parameter) with adjoint surface mesh sensitivities (which represent the derivative of a goal function with respect to surface mesh node position). A CAD-based design velocity computation method has been developed based on projection between discrete representations of perturbed geometries which can be linked to virtually any existing commercial CAD system. A key characteristic of the approach is that it can cope with the discontinuous changes in CAD model topology and face labelling that can occur under even small changes in CAD parameters. Use of the above approach allows computation of parametric sensitivities with respect to aerodynamic coefficients for native CAD parameters within feature-based commercial CAD modelling systems using adjoint data at a computational cost of just one adjoint analysis per objective function and one design velocity field evaluation per parameter. Gradient computation is demonstrated on test cases for an aerofoil model, a turbine blade model and a 3D wing model. Using these computed sensitivities enables the creation of a truly CAD-based aerodynamic optimisation system incorporating adjoint CFD data and using design velocities for computing geometric sensitivities and as input to a mesh deformation step. A prototype implementation of this system is presented and used to optimise a parametric CAD-based aerofoil model. In order to develop the approach further, future work should focus on resolving issues encountered when using design velocities for mesh deformation, extending the approach to more complex test cases, and potentially incorporating parametric effectiveness as a measure of the suitability of a given CAD parameterisation for optimisation purposes.
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Kim, Kyoungjin. "Computation of wake-passing effects on turbine blade boundary layers /." Digital version accessible at:, 1998. http://wwwlib.umi.com/cr/utexas/main.
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Van, Rooij Michael P. C. "Development of a three-dimensional multistage inverse design method for aerodynamic matching of axial compressor blading." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2008. http://wwwlib.umi.com/cr/syr/main.
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Feldová, Petra. "Optimalizace zadního křídla závodního vozu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-399571.
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This master’s thesis is focused on optimization of rear wing of sport car by using open-source software. The optimization of 2D profile of the rear wing is present in this thesis. Python environment was chosen for optimization and evolutionary algorithm was is used as optimization function. This algorithm is further connected to Xfoil software, which is computing aerodynamic characteristic. The ratio of the lift and drag coefficients (C_L/C_D) is chosen as parameter which considers the aerodynamic efficiency. The CFD computation of flowing around the whole car is provided in open-source software OpenFOAM. . The profile optimization results to approximately 7.9 % raise of the parameter C_L/C_D, in the same wing stability. The main benefit of this work is to use open-source software for the optimization and CFD analysis, which in future might save company’s resources by not buying expensive commercial software licenses.
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Wu, Gangwei. "Drag reduction in large diameter hydraulic capsule pipeline /." free to MU campus, to others for purchase, 1998. http://wwwlib.umi.com/cr/mo/fullcit?p9904874.
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Shi, Yijian. "Off-design waverider flowfield CFD simulation /." free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9717164.
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Cunningham, John B. "Field Testing the Effects of Low Reynolds Number on the Power Performance of the Cal Poly Wind Power Research Center Small Wind Turbine." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2249.
Full textAbstract:
This thesis report investigates the effects of low Reynolds number on the power performance of a 3.74 m diameter horizontal axis wind turbine. The small wind turbine was field tested at the Cal Poly Wind Power Research Center to acquire its coefficient of performance, Cp, vs. tip speed ratio, λ, characteristics. A description of both the wind turbine and test setup are provided. Data filtration and processing techniques were developed to ensure a valid method to analyze and characterize wind power measurements taken in a highly variable environment. The test results demonstrated a significant drop in the wind turbine’s power performance as Reynolds number decreased. From Re = 2.76E5 to Re = 1.14E5, the rotor’s Cp_max changed from 0.30 to 0.19. The Cp vs. λ results also displayed a clear change in shape with decreasing Reynolds number. The analysis highlights the influence of the rotor’s Cl /Cd characteristics on the Cp vs. λ curve’s Reynolds number dependency. By not accounting for the effects of varying Reynolds number below the critical value for a rotor operating at constant λ, the design of the rotor planform may overestimate the actual performance of the turbine in real-world conditions. This problem is more evident in distributed-scale wind turbines, compared to utility-scale ones, because of the significantly shorter chord lengths, and therefore increased wind speed range where this effect occurs. Lastly, the wind turbine’s future control method and annual energy production are evaluated using the test results.
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Paciano, Eric N. "Qualitative Methods Used to Develop and Characterize the Circulation Control System on Cal Poly's AMELIA." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1153.
Full textAbstract:
The circulation control system onboard Cal Poly's Advanced Model for Extreme Lift and Improved Aeroacoustics was a critical component of a highly complex wind tunnel model produced in order to fulfill the requirements of a NASA Research Announcement awarded to David Marshall of the Aerospace Engineering Department. The model was based on a next generation, 150 passenger, regional, cruise efficient, short take-off and landing concept aircraft that achieved high lift through circulation control wings and over-the-wing mounted engines. The wind tunnel model was 10-ft in span, used turbine propulsion simulators, and had a functioning circulation control system driven from tunnel supplied high pressure air. Wind tunnel test results will be compiled into an open-source database intended for validation of predictive tools whose purpose is to advance the state- of-the-art in predictive capabilities for the next generation aircraft configurations.
The model's circulation control system produced highly directional, nonuniform flow, and required significant modification in order to generate flow suitable for representation in predictive software. The effort and methods used to generate uniform flow along the circulation control slots is detailed herein. Additionally the results of the system characterization are presented and include a thorough analysis of the slot height, the wing symmetry, and total pressure at the circulation control jet exit. These datasets are intended to aid in making adjustments to the simulation such that it accurately reflects the condition at which the model was tested.
Many flow visualization results from the wind tunnel test are also presented to serve as a medium of comparison for results from predictive tools. Oil flow visualization was conducted at many test conditions and provides insight to AMELIA's surface flow in blown and unblown regions. Of particular interest were streamlines at the wingblend, which exhibited some outboard turning, and streamlines on the lower surface where the leading edge stagnation point was investigated. Smoke flow visualization was also utilized to explore the flowfield. The deflection of a individual streamline, under the influence of a changing discharge coefficient as investigated along with the discharge coefficients effect on the extended flowfield. Collectively, the images depict the massive augmentation of the flowfield caused by the presence of the circulation control wing.
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Foschi, Edoardo. "Design of a return circuit for an open loop wind tunnel." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21536/.
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This work is about the design of two different solutions of a return circuit for the subsonic open loop wind tunnel of the University of Bologna placed in the laboratory of aerodynamics. The possibility of realizing a return circuit was born from the idea of moving the current wind tunnel to a different place. Realizing a closed-type wind tunnel could permit a better installation with reduced costs since the starting point of the project is an existing tunnel. Two different design solutions are shown in order to satisfy different conditions of allocation: one model has vertical development, the other has horizontal development. The conceptual phase is followed by a study of the pressure losses in order to evaluate which design solution could be the best.
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Abramchuk, Vagner. "Estudo da força de arrasto sobre veículos de transporte de pessoas empregando CFD." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2014. http://hdl.handle.net/10183/96315.
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Com o avanço tecnológico dos computadores e o desenvolvimento de programas de simulação de fluidos, propiciando resultados cada vez mais sofisticados e eficazes, ocorreu uma redução significativa no tempo e nos custos computacionais para conceber veículos mais seguros e com menos agressão ao meio ambiente, devido ao seu menor consumo de combustível. Contudo, mesmo com o uso da Dinâmica dos Fluidos Computacional bastante disseminado, ainda são divergentes as informações sobre o nível de concordância esperado entre os resultados obtidos, por meio da simulação, quando comparada com os resultados medidos experimentalmente. Este trabalho apresenta uma sequencia metodológica para determinação das forças de arrasto sobre um veículo de transporte de pessoas (ônibus), de maneira a transmitir a compreensão dos fenômenos que envolvem o problema, a sequencia necessária de simulações e conceitos que devem ser atribuídos para obtenção de respostas coerentes. Primeiramente é abordada a análise de problemas com respostas experimentais disponíveis e assim validando a metodologia de simulação para cada parâmetro abordado, domínio, malha, discretização da camada limite e modelos de turbulência. Com base nas definições destes parâmetros são realizadas as simulações de um problema em escala real do escoamento de fluidos sobre um ônibus. A metodologia empregada para estimar os parâmetros de simulação é apresentada em forma de uma sequencia de cálculos, de fácil utilização. Os resultados demonstram que o uso do método numérico na criação de veículos pode ser ampliado, com significativa redução de ensaios experimentais. A análise numérica apresentada ratifica a metodologia numérica como importante ferramenta para aprimorar o projeto de veículos, com menor coeficiente de arrasto e maior estabilidade aerodinâmica, com isto proporcionando a redução do consumo de combustível, somados com benefícios secundários significativos, tais como, baixo acúmulo de sujeira, melhorando a visibilidade, ruído aerodinâmico reduzido e até menor fadiga do condutor.The technological advancement of computers and the development of fluid simulation software providing results increasingly sophisticated and effective, has resulted in a significant reduction in time and computational cost to develop safer vehicles with less harm to the environment due to its lower fuel consumption. However, even with quite widespread Computational Fluid Dynamics use, there is still conflicting information on the expected level of agreement among the results obtained by simulation, when compared with the experimentally measured results. This work presents a methodological sequence to determine the drag force on a vehicle for people transportation (bus ), in order to convey the understanding of phenomena involving the problem , the required sequence of simulations, and concepts that should be assigned to obtain coherent answers. At first, one approaches the analysis of problems with available experimental answers, thus validating the simulation methodology for each parameter approached, domain , mesh ,discretization of the boundary layer and turbulence models. Based on the definitions of these parameters, simulations of an actual scale problem of fluid flow on a bus are performed. The methodology used to estimate the simulation parameters is presented in the form of a sequence of calculations easy to use. The results show that the use of the numerical method for creating vehicles can be expanded with a significant reduction in experimental tests. The numerical analysis presented confirms the numerical methodology as an important tool to upgrade the design of vehicles, with lower drag coefficient and greater aerodynamic stability, thus providing a reduction of fuel consumption, added to significant secondary benefits, such as low dirt accumulation, improving visibility, reduced aerodynamic noise and even less driver fatigue.