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151.
Derek Bradley Malcolm Lawes Morkous S. Mansour 《Flow, Turbulence and Combustion》2011,87(2-3):191-204
The paper reviews the practical problems in measuring a turbulent burning velocity that gives the mass rate of burning. These largely centre on identifying an appropriate flame surface to associate with the turbulent burning velocity, u t , and the density of the unburned mixture. Such a flame surface has been identified, in terms of the mean reaction progress variable, $\bar {c}$ , for explosive flame propagation in a fan-stirred bomb. Measurement of $\bar {c}$ makes possible an estimation of the flame surface density, ??, from the relationship ${\it \Sigma} =k\bar {c}\left( {1-\bar {c}} \right)$ . It is shown that in such explosions, mass rates of burning derived from the measured total flame surface area agreed well with those found from the measured turbulent burning velocity. Flamelet considerations identify appropriate dimensionless correlating parameters for u t . As a result, correlations of turbulent burning velocity divided by the effective rms turbulent velocity, are plotted against the turbulent Karlovitz stretch factor, K, for different values of the Markstein number for flame strain rate, Masr. These plots cover a wide range of variables, including pressure and fuels, and are indicative of different regimes of turbulent combustion. At the lower values of K, there is some evidence of increases in u t and k due to high-frequency flame surface wrinkling arising from flame instabilities. These increase as Masr becomes more negative. It is found from the developed value of the mean flame surface density throughout the flame brush that, to a first approximation, an increase in u t for a given mixture is accompanied by a proportional increase in the volume of the brush. The analysis shows that the volume fraction of the turbulent flame brush that is reacting is quite small. 相似文献
152.
Derek Booth Jack Burkart Xiaodong Cao Max Hallgren Zachary Munro Jason Snyder Tom Stone 《分析论及其应用》2019,35(2):192-204
This paper will develop a Li-Yau-Hamilton type differential Harnack estimate for positive solutions to the Newell-Whitehead-Segel equation on R^n.We then use our LYH-differential Harnack inequality to prove several properties about positive solutions to the equation,including deriving a classical Harnack inequality and characterizing standing solutions and traveling wave solutions. 相似文献
153.
Young Derek S. Chen Xi Hewage Dilrukshi C. Nilo-Poyanco Ricardo 《Advances in Data Analysis and Classification》2019,13(4):1053-1082
Advances in Data Analysis and Classification - Finite mixtures of (multivariate) Gaussian distributions have broad utility, including their usage for model-based clustering. There is increasing... 相似文献
154.
Subramanian V. Sankar Derek Y. Kamemoto William D. Bachalo 《Particle & Particle Systems Characterization》1993,10(6):321-331
A combined theoretical and experimental study has been conducted to evaluate the effectiveness of using large, hollow micro-balloons as LDV seed particles. The study has focused on the ability of phase Doppler systems to size hollow microballoons, the ability of large micro-balloons to respond to high frequency spatial and temporal flow field variations, and the overall advantages and disadvantages of using large microballoons instead of conventional LDV seed particles, such as very small water droplets or polystyrene latex (PSL) particles. This paper discusses the development of a theoretical phase Doppler response model for stratified spheres, the experimental facility, and the theoretical and experimental results. 相似文献
155.
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157.
Evaluating Individual Market Power in Electricity Markets via Agent-Based Simulation 总被引:11,自引:0,他引:11
We use agent-based simulation in a coordination game to analyse the possibility of market power abuse in a competitive electricity market. The context of this was a real application to the England and Wales electricity market as part of a Competition Commission Inquiry into whether two particular generators could profitably influence wholesale prices. The research contributions of this paper are both in the areas of market power and market design policy issues for electricity markets, and in the methodological use of large industry-wide evolutionary simulation models. 相似文献
158.
Charles J. K. Batty Ola Bratteli Palle E. T. Jørgensen Derek W. Robinson 《Journal of Geometric Analysis》1995,5(4):427-443
We establish that heat diffusion with periodic conductivity is governed by two scales. The small time diffusion is described by the geodesic distance but the large time behaviour is dictated by the distance associated with an homogenized system obtained by a suitable averaging process. Our methods are quite general and apply to diffusion on a stratified Lie group. 相似文献
159.
A simple method for modelling the textures of liquid-crystalline phases, recently proposed by Bedford et al., is here rewritten in matrix form. A formal similarity is found between their method and the continuum theory of liquid crystals. Disclination patterns are simulated by solving a modified matrix equation. 相似文献
160.