The impact of improvement in vehicle aerodynamics mainly reflects in lower fuel consumption and lower carbon dioxide emissions into the atmosphere. The governments of many countries support continuous aerodynamics' improvement programs as a way of mitigating the energy crisis and atmospheric pollution. This work has the main goal to validate experimental and numerical techniques for application in road vehicles. The experimental results were obtained through the analysis of the flow around a standard body with simple geometry called Ahmed Body, using hot wire anemometry from experiments in wind tunnel. It was also proposed a computational validation using a commercial software (Star CCM +) to further analyze the flow and to corroborate the experimental results. Both results were compared and allowed characterizing the flow around the vehicle. The results obtained analyzing the Ahmed Body aimed further application on aerodynamics of heavyduty vehicles, which is an ongoing research being developed at the Experimental Aerodynamics Research Center -CPAERO, in Brazil.

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A hybrid numerical-analy tical solution for two-dimensional transient-free convection is presented and applied to a vertical porous cavity, based on application of the ideas in the generalized integral transform technique ( GITT) . The integral transformation process reduces the original coupled partial differential equations ( PDEs) , for stream function and temperature, into an in nite system of nonlinear ordinary differential equations ( ODEs) for the transformed potentials, which is adaptively truncated and numerically solved through subroutine NDSolve from the Mathematica software system. All the analytical steps in the solution procedure are symbolically evaluated through the Mathematica package, mixing with the numerical computations and graphic representation. INTROD UCTIONTransport phenomena in porous media represent an important segment of the heat and mass transfer ¢eld and have a variety of applications in engineering. The effect of free convection as a result of the gravitational body force is of particular interest from both practical and theoretical points of view. Engineering applications include, among others, thermal insulations, radioactive waste disposal, solar energy collectors, and geothermal energy analysis. Other applications of the porous medium modeling are discussed by Kakac°, Kilkis, , Kulacki, and Arinc°[1] and more recently by Kaviany [2]. In addition to the interesting physics pertinent to this class of problems, the associated system of coupled PDEs for temperature and stream function provides an important test case in the development of new solution techniques for convection-diffusion problems.Within the last two decades, the ideas in the so-called GITT [3,4,5], progressively advanced toward the establishment of an alternative hybrid numerical-analytical approach based on the formal analytical principles in the classical integral transform method [6] for a priori nontransformable diffusion and convection-diffusion problems. This note is one more step in the effort to reach the full potential of this promising approach by testing its performance in the class of problems represented by transient-free convection within a two-dimensional

The component integration of a class of hypersonic high-lift configurations known as waveriders into hypersonic cruise vehicles was evaluated. A wind-tunnel model was developed which integrates realistic vehicle components with two waverider shapes, referred to as the "straight-wing" and "cranked-wing" shapes. Both shapes were conical-flow-derived waveriders for a design Mach number of 4.0. Experimental data and limited computational fluid dynamics (CFD) predictions were obtained over a Mach number range of 1.6 to 4.63 at a Reynolds number of 2.0x10 6 per foot. The CFD predictions and flow visualization data confirmed the shock attachment characteristics of the baseline waverider shapes and illustrated the waverider flow-field properties. Experimental data showed that no significant performance degradations , in terms of maximum lift-to-drag ratios, occur at off-design Mach numbers for the waverider shapes and the integrated configurations. A comparison of the fully-integrated waverider vehicles to the baseline shapes showed that the performance was significantly degraded when all of the components were added to the waveriders, with the most significant degradation resulting from aftbody closure and the addition of control surfaces. Both fully-integrated configurations were longitudinally unstable over the Mach number range studied with the selected center of gravity location and for unpowered conditions. The cranked-wing configuration provided better lateral-directional stability characteristics than the straight-wing configuration.

Resumo O trabalho proposto trata-se de uma manipulação matemática baseada em conceitos físicos, com o objetivo de descrever o problema de estabilidade de um controlador automático de uma máquina a vapor.Palavras Chave: Equações diferenciais, Campos de vetores, Retrato de fase e Estabilidade assintótica IntroduçãoA máquina a vapor tem o intuito de transformar energia térmica em energia mecânica, sendo largamente utilizada no período da Revolução Industrial, a partir do final do século XVIII. Entre outros mecanismos da mesma destaca-se o "controlador centrífugo de Watt", responsável por manter a estabilidade da máquina controlando a saída de vapor e, por consequência, as forças envolvidas no trabalho da máquina.Através do estudo da classificação das equações diferenciais lineares no plano, de campos de vetores para a análise dos retratos de fases das equações diferenciais que regem o problema e da estabilidade assintótica em pontos de equilíbrio; pode-se concluir o trabalho matemático sobre a máquina e chegar numa desigualdade que fornece informações suficientes para controlar a estabilidade da máquina a vapor.A princípio este mecanismo funcionava bem, fazendo com que a máquina mantivesse a velocidade de rotação desejada. O estado ideal da máquina pode ser visto como um ponto de equilíbrio do sistema. Como os controladores faziam o sistema voltar ao estado ideal quando houvesse pequenas perturbações, tal estado podia ser visto como um ponto de equilíbrio estável.Com o avanço da tecnologia houve uma melhoria nos materiais utilizados nos controladores. Paradoxalmente, esta melhoria acarretou no mau funcionamento dos mesmos. Maxwell em [7] e Vichégnadski em [9], apresentaram explicações e consequentemente soluções para tal perda de estabilidade.A seguir descrevemos a explicação dada por Vichégnadski em [9], recompilada por Doering e Lopes em [4].A figura abaixo esquematiza a máquina a vapor utilizada no século XVIII. * Trabalho de Iniciação científica †