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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Bepiločio skraidančio sparno aerodinaminių charakteristikų tyrimas / Research of aerodynamic characteristics of unmanned flying wing

Masiulis, Paulius 25 June 2014 (has links)
Šiame darbe nagrinėjamos bepiločio skraidančio sparno aerodinaminės charakteristikos. Pasirinktas sparno profilis EPPLER 328. Pirmiausia išanalizuojami skaitiniai aerodinaminių charakteristikų tyrimo metodai. Atlikus skaičiavimus pagal pasirinktus aspektus, naudojant programą XFLR5 gauti duomenys apibendrinami bei išanalizuojami. Ištirtos keliamosios jėgos koeficientų, pasipriešinimo jėgos koeficientų, aerodinaminės kokybės reikšmės esant atitinkamiems atakos kampams. Naudojantis tyrimo rezultatais padarytas bepilotis skraidančio sparno orlaivis ir atlikti skrydžiai. Visa informacija apibendrinama ir pateikiamos gautų rezultatų išvados. Darbo apimtis – 66 p. teksto be priedų, 39 paveikslai, 6 lentelės, 24 bibliografiniai šaltiniai. / The investigation analyzes unmanned flying wing aerodynamic characteristics. Choosen airfoil EPPLER 328. Firstly, analyzing theoretical calculation methods. All relative data compared and analyzed after calculation with program XFLR5. Analyzed lift force coefficient, drag force coefficient, aerodynamic coefficient under realative angles of attack. Unmanned flying wing was built using the results of compared and analyzed aerodynamic data and test flights were made. All information summarized and produced conclusion. Thesis consists of: 66 p. text without appendixes, 39 pictures, 6 tables, 24 bibliographical entries.
2

An?lise aerodin?mica de perfis de asa para aeronaves experimentais tipo jn-1

Ribeiro, Fernanda Alves 25 February 2011 (has links)
Made available in DSpace on 2014-12-17T14:58:10Z (GMT). No. of bitstreams: 1 FernandaAR_DISSERT.pdf: 8485678 bytes, checksum: eca5de592a0a48a71b782d8289da3a31 (MD5) Previous issue date: 2011-02-25 / The great importance in selecting the profile of an aircraft wing concerns the fact that its relevance in the performance thereof; influencing this displacement costs (fuel consumption, flight level, for example), the conditions of flight safety (response in critical condition) of the plane. The aim of this study was to examine the aerodynamic parameters that affect some types of wing profile, based on wind tunnel testing, to determine the aerodynamic efficiency of each one of them. We compared three types of planforms, chosen from considerations about the characteristics of the aircraft model. One of them has a common setup, and very common in laboratory classes to be a sort of standard aerodynamic, it is a symmetrical profile. The second profile shows a conFiguration of the concave-convex type, the third is also a concave-convex profile, but with different implementation of the second, and finally, the fourth airfoil profile has a plano-convex. Thus, three different categories are covered in profile, showing the main points of relevance to their employment. To perform the experiment used a wind tunnel-type open circuit, where we analyzed the pressure distribution across the surface of each profile. Possession of the drag polar of each wing profile can be, from the theoretical basis of this work, the aerodynamic characteristics relate to the expected performance of the experimental aircraft, thus creating a selection model with guaranteed performance aerodynamics. It is believed that the philosophy used in this dissertation research validates the results, resulting in an experimental alternative for reliable implementation of aerodynamic testing in models of planforms / A import?ncia na escolha do perfil de asa de uma aeronave ? fun??o de sua relev?ncia no seu desempenho; influenciando desde os custos de deslocamento (consumo de combust?vel, n?vel de v?o, por exemplo), a condi??es de seguran?a do v?o (resposta em condi??es cr?ticas) do avi?o. O objetivo deste trabalho foi analisar quatro perfis de asa a fim de determinar alguns dos principais par?metros envolvidos no comportamento aerodin?mico e determinar a efici?ncia de cada um deles baseado em experimenta??o em t?nel de vento. Compararam-se quatro perfis de asa, escolhidos a partir de considera??es acerca das caracter?sticas do modelo da aeronave. Um deles apresenta uma configura??o sim?trica usual, sendo muito comum em aulas de laborat?rio por ser uma esp?cie de padr?o aerodin?mico. O segundo perfil apresenta uma configura??o do tipo c?ncavo-convexo; o terceiro, tamb?m ? um perfil c?ncavo-convexo, por?m, com aplica??o distinta do segundo; e, finalmente, o quarto aerof?lio possui um perfil plano-convexo. Para a realiza??o do experimento utilizou-se um t?nel aerodin?mico do tipo circuito aberto, onde analisaram-se as distribui??es de press?o em toda a superf?cie de cada perfil. De posse da curva polar de arrasto de cada perfil de asa pode-se, a partir da base te?rica deste trabalho, relacionar as caracter?sticas aerodin?micas ? expectativa de desempenho da aeronave experimental tipo JN-1, gerando assim um modelo de sele??o com garantia de performance aerodin?mica. Acredita-se que a filosofia de pesquisa utilizada nesta disserta??o legitima os resultados obtidos, consistindo-se em uma alternativa experimental confi?vel para execu??o de testes aerodin?micos em modelos de perfis de asa
3

Design- och simuleringsstudie av flödeshus och sensorkropp / A design and simulation study of a sensor body and flow housing

Larsson Sparr, Klara, Muhonen, Mathias January 2020 (has links)
I detta arbete har ett koncept utvecklats för en flödesmätningsmetod med en intern sensorkropp samt bibehållen flödeshastighet. Denna mätmetod består av en sensorkropp i ett flödeshus där mätningen av flödet utförs med hjälp av pitotrörsberäkningar. Två olika lösningar presenteras i detta arbete, där skillnaderna grundar sig i utformningen av sensorkroppen. Sensorkroppens tvärsnitt är liknande för båda lösningarna. Den ena lösningen är rotationssymmetrisk i centrum av röret medan den andra går från vägg till vägg centrerat i röret. För att åstadkomma bibehållen flödeshastighet så utfördes beräkningar för att modellera flödeshuset, så att flödets tvärsnittsarea motsvarade arean i röret utan sensorkropp. I dessa beräkningar ingick även att kompensera för ökade solida ytor, då dessa ytor skapar gränsskikt där flödets hastighet sänks. Jämförelser mellan arbetets genererade koncept och uppdragsgivarens nuvarande produkter utfördes. Jämförelsen resulterade i flera områden där arbetets koncept skulle kunna komplettera redan befintliga produkter. / In this project a concept for flow measurement has been developed, where there is an internal sensor body as well as a constant flow speed. This measurement method consists of a sensor body in a flow housing where the flow measurement is done using conventional pitot tube calculations. Two different solutions are presented in this work, the differences between the two solutions are based on the design of the sensor body. The cross-section of the sensor body is similar for both solutions, but one solution is rotationally symmetrical while the other goes from wall to wall. Both sensor bodies are centered in the tube. To accomplish continuous flow speed, calculations were made to model the flow housing, so the cross-sectional area of the flow corresponded to the area of the tube without the sensor body. In these calculations a compensation factor for increased solid surface area were included, as this area creates a boundary layer that lowers the flow speed and changes based on the design of the sensor body. Comparisons between the concept in this project and the commissioner's current products were made. This comparison resulted in several areas where this projects concept could complement existing products.

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