Large eddy simulations and direct numerical simulations of high speed turbulent reacting flows

This research is involved with the implementations of advanced computational schemes based on large eddy simulations (LES) and direct numerical simulations (DNS) to study the phenomenon of mixing and its coupling with chemical reactions in compressible turbulent flows. In the efforts related to LES, a research program was initiated to extend the present capabilities of this method for the treatment of chemically reacting flows, whereas in the DNS efforts, focus was on detailed investigations of the effects of compressibility, heat release, and nonequilibrium kinetics modeling in high speed reacting flows. The efforts to date were primarily focussed on simulations of simple flows, namely, homogeneous compressible flows and temporally developing hign speed mixing layers. A summary of the accomplishments is provided

Large Eddy Simulations (LES) and Direct Numerical Simulations (DNS) for the computational analyses of high speed reacting flows

The principal objective is to extend the boundaries within which large eddy simulations (LES) and direct numerical simulations (DNS) can be applied in computational analyses of high speed reacting flows. A summary of work accomplished during the last six months is presented

Cars, capitalism and ecological crises: understanding systemic barriers to a sustainability transition in the German car industry

In the face of climate and ecological crises, it is vital that car use be reduced, while simultaneously shifting towards different powertrains and reducing the size, weight and energy demand of vehicles. This poses a challenge to the global car industry, as its business model historically centres on selling more and larger cars. In this context, the purpose of this paper is to examine the social-ecological limits of industrial restructuring in Germany. A narrative literature review through the lens of Marxian political economy sheds light on intertwined system-immanent barriers to achieving social and ecological sustainability at the sectoral level. Consequently, powertrain electrification is structured by technological dynamism, which fuels appropriation in the quest for metals and rare earths, with significant social and ecological disadvantages. This generates an impasse for the industry’s transition strategies. Understanding how capitalist tendencies generate interlaced and mutually re-enforcing barriers to achieving social-ecological sustainability is key to understanding why industrial transitions are insufficient from a social-ecological perspective

Large eddy simulations and direct numerical simulations of high speed turbulent reacting flows

The main objective is to extend the boundaries within which large eddy simulations (LES) and direct numerical simulations (DNS) can be applied in computational analyses of high speed reacting flows. In the efforts related to LES, we were concerned with developing reliable subgrid closures for modeling of the fluctuation correlations of scalar quantities in reacting turbulent flows. In the work on DNS, we focused our attention to further investigation of the effects of exothermicity in compressible turbulent flows. In our previous work, in the first year of this research, we have considered only 'simple' flows. Currently, we are in the process of extending our analyses for the purpose of modeling more practical flows of current interest at LaRC. A summary of our accomplishments during the third six months of the research is presented

Your money or your life? The carbon-development paradox

The relationship between human health and well-being, energy use and carbon emissions is a foremost concern in sustainable development. If past advances in well-being have been accomplished only through increases in energy use, there may be significant trade-offs between achieving universal human development and mitigating climate change. We test the explanatory power of economic, dietary and modern energy factors in accounting for past improvements in life expectancy, using a simple novel method, functional dynamic decomposition. We elucidate the paradox that a strong correlation between emissions and human development at one point in time does not imply that their dynamics are coupled in the long term. Increases in primary energy and carbon emissions can account for only a quarter of improvements in life expectancy, but are closely tied to growth in income. Facing this carbon-development paradox requires prioritizing human well-being over economic growth

Measurement of the Sintering Dynamics of polymeric powders at Near SLS Conditions

The sintering dynamics of materials used in the Selective Laser Sintering process impact greatly the thermal conditions of the powder bed. An experimental setup was developed to obtain sintering rate information at conditions very near to those of the SLS process. The system consists of a powder sample heated by a CO2 laser while maintained at constant thermal boundary conditions. The powder height is measured by means of an optical sensor, which avoids stress on the powder and allows fast data. acquisition. This paper discusses experiments conducted with this apparatus and further compares the obtained results with theoretical models and the previous work of others.Mechanical Engineerin

Large eddy simulations and direct numerical simulations of high speed turbulent reacting flows

This research is involved with the implementation of advanced computational schemes based on large eddy simulations (LES) and direct numerical simulations (DNS) to study the phenomenon of mixing and its coupling with chemical reactions in compressible turbulent flows. In the efforts related to LES, a research program to extend the present capabilities of this method was initiated for the treatment of chemically reacting flows. In the DNS efforts, the focus is on detailed investigations of the effects of compressibility, heat release, and non-equilibrium kinetics modelings in high speed reacting flows. Emphasis was on the simulations of simple flows, namely homogeneous compressible flows, and temporally developing high speed mixing layers