![]() First of all, recent analysis tools based on momentum and energy tubes (Meyers and Meneveau (2013)) are extended to the present compressible flow context and applied to the mean-flow structure of turbulent flow within the ejector. In this study, we propose two different and complementary approaches. This work aims at providing novel insights into the quantification and the location of the transfers and the irreversibilities within supersonic ejectors, and their connection with the entrainment. The simulation results are qualitatively consistent with the reported experimental measurements and they demonstrate that in the case of supersonic nozzles, the exit jet pattern is characterized by high uniformity, absence of Mach disks, and bounded shape for a long distance especially under the desired design operating conditions. Moreover, the model has been optimized to be effectively used for engineering purposes. The effect of the turbulent viscosity has been considered through the proposed model to better simulate real conditions. Finally, the proposed simulations have been validated by comparing the results with experimental observations reported in previous literature. Quasi 1-D gas dynamics theory has been used to calculate the desired design operating condition, and then an axisymmetric 2-D model has been created using the OpenFOAMⓇ Computational Fluid Dynamics (CFD) toolbox to simulate the gas-assisted laser cutting flow through the modeled supersonic nozzle. In this paper, the exit jet from supersonic nozzle has been studied, analyzed, and simulated under three different operating conditions, namely desired design, under-expansion, and over-expansion to illustrate the effect of these operating conditions on the dynamic characteristics of the exit jet. However, most of these studies have been done using conical nozzles. ![]() ![]() Many studies have been done to illustrate the effect of this parameter on both laser cutting quality and laser cutting capability. The operating pressure of gas-assisted laser cutting and the resulting exit jet pattern is one of the most important process parameters in high-pressure laser cutting. Os resultados médios analisados neste artigo são o coeficiente de arrasto, velocidade média e coeficiente de pressão. Os resultados do SST k-ω foram mais próximos dos valores de referência porque é o modelo mais aplicado em casos que envolvem gradientes adversos e separação da camada limite. Esf evm model pack download software#Os valores obtidos para o coeficiente de arrasto foram comparados com dados de simulações semi-empíricas implementas no software comercial PRODAS®. As simulações numéricas desenvolvidas usaram as equações médias de Navier-Stokes (RANS) para o escoamento bidimensional e em regime permanente a partir dos modelos de turbulência Spalart-Allmaras e SST k-ω. O objetivo deste trabalho é observar a força de arrasto existente sobre uma geometria axissimétrica de um projetil calibre 155 mm. ![]() Como são lançados em velocidades transônicas ou supersônicas, os efeitos de compressibilidade e de turbulência se fazem presentes. A aerodinâmica de um projetil de artilharia é um caso de escoamento complexo em que o uso da dinâmica dos fluidos computacional pode ser aplicado. ![]()
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