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@MastersThesis{Torres:2017:AnAtEf,
               author = "Torres, Luis Carlos Roldan",
                title = "Angle of attack effect in the aerothermodynamics of a hypersonic 
                         vehicle with a surface discontinuity of gap type",
               school = "Instituto Nacional de Pesquisas Espaciais (INPE)",
                 year = "2017",
              address = "Cachoeira Paulista",
                month = "2017-03-29",
             keywords = "direct simulation Monte Carlo, escoamento hipers{\^o}nicos, 
                         escoamento rarefeito, filete, ve{\'{\i}}culos hipers{\^o}nicos, 
                         direct simulation Monte Carlo, hypersonic flow, rarefied flow, gap 
                         flow, hypersonic vehicle.",
             abstract = "The development of hypersonic vehicles has become a topic of 
                         interest in recent years, since has made it possible to reach 
                         inaccessible places such as orbital flights. The construction of 
                         these vehicles must be made with specials materials, and must have 
                         an efficient aerodynamic shape to withstand high speeds, high 
                         temperatures and significant pressure changes. The study described 
                         in this dissertation was undertaken with the objective to 
                         investigate the impact of discontinuities present on the surface 
                         of hypersonic space vehicles. In pursuit of this goal, 
                         computational simulations of a low-density hypersonic flow over a 
                         flat plate with a gap has been performed by using the Direct 
                         Simulation Monte Carlo method. The simulations provided 
                         information about the nature of the flowfield structure and the 
                         aerodynamic surface properties on the gap resulting from 
                         variations in the length-to-depth (L/H) ratio and variations in 
                         the angle of attack. A description of the flowfield properties, 
                         such as velocity, density, pressure and temperature, and 
                         aerodynamics surface quantities, such as, number flux, heat 
                         transfer, pressure and skin friction, were obtained by a numerical 
                         method that properly account for non-equilibrium effects in the 
                         transition flow regime. Results for a gap defined by L/H ratio of 
                         1, 1/2, 1/3 and 1/4, and flow with angle of attack of 10, 15 and 
                         20 degrees, were compared to those of a flat plate without a gap 
                         with zero-degree angle of incidence. The analysis showed that the 
                         flow topology inside the gap with incidence is slightly different 
                         from that for zero-degree angle of incidence for the L/H ratio 
                         investigated. It was found that the maximum values for the heat 
                         transfer, pressure and skin friction coefficients inside the gap 
                         took place on the gap forward face. It was also found that, 
                         maximum values for heat transfer coefficient inside the gaps 
                         increased with increasing the angle of attack \$\alpha\$. 
                         Nevertheless, it was observed that these maximum values are 
                         smaller than those observed in a flat-plate without a gap for the 
                         corresponding angle of attack. As a result, in terms of pressure, 
                         the presence of the gap on the vehicle surface can not be ignored 
                         in the vehicle design. RESUMO: O desenvolvimento de 
                         ve{\'{\i}}culos hipers{\^o}nicos tem se tornado um tema de 
                         interesse nos {\'u}ltimos anos, considerando-se a possibilidade 
                         de se chegar com tais ve{\'{\i}}culos a locais at{\'e} 
                         ent{\~a}o inacess{\'{\i}}veis como os voos orbitais. A 
                         constru{\c{c}}{\~a}o desses ve{\'{\i}}culos exige materiais 
                         especiais e deve apresentar uma forma aerodin{\^a}mica eficiente 
                         para resistir altas velocidades al{\'e}m de temperaturas elevadas 
                         e mudan{\c{c}}as de press{\~a}o significativas. O estudo 
                         descrito nesta disserta{\c{c}}{\~a}o foi realizado com o 
                         objetivo de investigar o impacto de descontinuidades presentes na 
                         superf{\'{\i}}cie de ve{\'{\i}}culos espaciais 
                         hipers{\^o}nicos. Em busca deste objetivo, simula{\c{c}}{\~o}es 
                         computacionais de um escoamento hipers{\^o}nico rarefeito sobre 
                         uma placa plana, foi realizada usando-se o m{\'e}todo Direct 
                         Simulation Monte Carlo. As simula{\c{c}}{\~o}es forneceram 
                         informa{\c{c}}{\~o}es sobre a natureza da estrutura do 
                         escoamento, propriedades primarias e propriedades 
                         aerodin{\^a}micas, devido a varia{\c{c}}{\~o}es na raz{\~a}o 
                         comprimento-profundidade (L/H), e varia{\c{c}}{\~o}es no 
                         {\^a}ngulo de ataque. Uma descri{\c{c}}{\~a}o das propriedades 
                         primarias, tais como velocidade, massa espec{\'{\i}}fica, 
                         press{\~a}o e temperatura, e das quantidades aerodin{\^a}mica, 
                         tais como transfer{\^e}ncia de calor, press{\~a}o e atrito na 
                         superf{\'{\i}}cie, foi obtida por um m{\'e}todo num{\'e}rico 
                         que leva em conta os efeitos de n{\~a}o-equil{\'{\i}}brio no 
                         regime de transi{\c{c}}{\~a}o. Os resultados para um filete 
                         definido por uma raz{\~a}o L/H de 1, 1/2, 1/3 e 1/4, e com 
                         {\^a}ngulo de ataque do escoamento de 10, 15 e 20 graus, foram 
                         comparados com os de uma placa plana sem a presen{\c{c}}a de um 
                         filete. A an{\'a}lise mostrou que a estrutura do escoamento 
                         dentro do filete com {\^a}ngulo de ataque {\'e} ligeiramente 
                         diferente daquela com zero grau de incid{\^e}ncia para cada 
                         raz{\~a}o L/H investigada. Verificou-se que os valores 
                         m{\'a}ximos para os coeficientes de transfer{\^e}ncia de calor, 
                         press{\~a}o e coeficiente de atrito ocorreram na 
                         superf{\'{\i}}cie a montante do escoamento dentro do filete. 
                         Verificou-se tamb{\'e}m que, os valores m{\'a}ximos para o 
                         coeficiente de transfer{\^e}ncia de calor dentro do filete 
                         aumentaram com o aumento do {\^a}ngulo de ataque \$\alpha\$. 
                         Como resultado, em termos de press{\~a}o, a presen{\c{c}}a do 
                         filete sobre a superf{\'{\i}}cie do ve{\'{\i}}culo n{\~a}o 
                         pode ser ignorada no projeto do ve{\'{\i}}culo.",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)}",
            committee = "Santos, Wilson Fernando Nogueira dos (presidente/orientador) and 
                         Kalempa, Denize and Leite, Paulo Henrique Mineiro",
         englishtitle = "Efeito do {\^a}ngulo de ataque na aerotermodin{\^a}mica de um 
                         ve{\'{\i}}culo hipers{\^o}nico com descontinuidade na 
                         superf{\'{\i}}cie do tipo filete.",
             language = "en",
                pages = "185",
                  ibi = "8JMKD3MGP3W34P/3NU8MJS",
                  url = "http://urlib.net/rep/8JMKD3MGP3W34P/3NU8MJS",
           targetfile = "publicacao.pdf",
        urlaccessdate = "04 dez. 2020"
}


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