scholarly journals An alternative formulation for exact scaling relations in hydrodynamic and magnetohydrodynamic turbulence

2016 ◽  
Vol 50 (1) ◽  
pp. 015501 ◽  
Author(s):  
Supratik Banerjee ◽  
Sébastien Galtier
2007 ◽  
Vol 575 ◽  
pp. 111-120 ◽  
Author(s):  
T. A. YOUSEF ◽  
F. RINCON ◽  
A. A. SCHEKOCHIHIN

This paper examines the consistency of the exact scaling laws for isotropic magnetohydrodynamic (MHD) turbulence in numerical simulations with large magnetic Prandtl numbers Pm and with Pm = 1. The exact laws are used to elucidate the structure of the magnetic and velocity fields. Despite the linear scaling of certain third-order correlation functions, the situation is not analogous to the case of Kolmogorov turbulence. The magnetic field is adequately described by a model of a stripy (folded) field with direction reversals at the resistive scale. At currently available resolutions, the cascade of kinetic energy is short-circuited by the direct exchange of energy between the forcing-scale motions and the stripy magnetic fields. This non-local interaction is the defining feature of isotropic MHD turbulence.


2009 ◽  
Vol 699 (1) ◽  
pp. L39-L42 ◽  
Author(s):  
Stanislav Boldyrev ◽  
Joanne Mason ◽  
Fausto Cattaneo

1985 ◽  
Vol 82 (2) ◽  
pp. 1063-1064 ◽  
Author(s):  
Larry Eno

2017 ◽  
Vol 24 (1) ◽  
pp. 87-106
Author(s):  
Wiharyanto Wiharyanto

The study aims to analyze about the low graduation and certification exam training participants of the procurement of goods / services of the government and its contributing factors, and formulate a strategy of education and training and skills certification exams procurement of goods / services of the government. Collecting data using the method of study documentation, interviews, and questionnaires. Is the official source of information on the structural and functional Regional Employment Board, as well as the participants of the training and skills certification exams procurement of goods / services of the government in Magelang regency government environment. Analysis using 4 quadrant SWOT analysis, to determine the issue or strategic factors in improving the quality of education and training and skills certification exams procurement of government goods / services within the Government of Magelang regency. The results show organizer position is in quadrant I, which is supporting the growth strategy, with 3 alternative formulation strategies that improve the quality of education and training and skills certification exams procurement of government goods / services, and conducts certification examination of the procurement of government goods / services with computer assisted test system (CAT). Based on the research recommendations formulated advice to the organizing committee, namely: of prospective participants of the training and skills certification exams procurement of goods / services the government should consider the motivation of civil servants, is examinees who have attended training in the same period of the year, the need for simulation procurement of goods / services significantly, an additional allocation of training time, giving sanction to civil servants who have not passed the exam, the provision of adequate classroom space with the number of participants of each class are proportional, as well as explore the evaluation of education and training and skills certification exams procurement of goods / services for Government of participants.


1998 ◽  
Vol 505 (2) ◽  
pp. 974-983 ◽  
Author(s):  
Pablo Dmitruk ◽  
Daniel O. Gomez ◽  
Edward E. DeLuca

Author(s):  
Pengfei (Taylor) Li ◽  
Peirong (Slade) Wang ◽  
Farzana Chowdhury ◽  
Li Zhang

Traditional formulations for transportation optimization problems mostly build complicating attributes into constraints while keeping the succinctness of objective functions. A popular solution is the Lagrangian decomposition by relaxing complicating constraints and then solving iteratively. Although this approach is effective for many problems, it generates intractability in other problems. To address this issue, this paper presents an alternative formulation for transportation optimization problems in which the complicating attributes of target problems are partially or entirely built into the objective function instead of into the constraints. Many mathematical complicating constraints in transportation problems can be efficiently modeled in dynamic network loading (DNL) models based on the demand–supply equilibrium, such as the various road or vehicle capacity constraints or “IF–THEN” type constraints. After “pre-building” complicating constraints into the objective functions, the objective function can be approximated well with customized high-fidelity DNL models. Three types of computing benefits can be achieved in the alternative formulation: ( a) the original problem will be kept the same; ( b) computing complexity of the new formulation may be significantly reduced because of the disappearance of hard constraints; ( c) efficiency loss on the objective function side can be mitigated via multiple high-performance computing techniques. Under this new framework, high-fidelity and problem-specific DNL models will be critical to maintain the attributes of original problems. Therefore, the authors’ recent efforts in enhancing the DNL’s fidelity and computing efficiency are also described in the second part of this paper. Finally, a demonstration case study is conducted to validate the new approach.


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