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The aim of this paper is to present a kinetic numerical scheme for the computations of transient pressurised flows in closed water pipes. Firstly, we detail the mathematical model written as a conservative hyperbolic partial differentiel…

Analysis of PDEs · Mathematics 2010-06-02 Christian Bourdarias , Stéphane Gerbi

Energy networks should strive for reliability. How can it be assessed, measured, and improved? What are the best trade-offs between investments and their worth? The flow-based framework for the reliability assessment of energy networks…

Systems and Control · Electrical Eng. & Systems 2021-08-03 Fabio Luiz Usberti , Celso Cavellucci , Christiano Lyra

We introduce and investigate reroutable flows, a robust version of network flows in which link failures can be mitigated by rerouting the affected flow. Given a capacitated network, a path flow is reroutable if after failure of an arbitrary…

Discrete Mathematics · Computer Science 2017-04-28 Jannik Matuschke , S. Thomas McCormick , Gianpaolo Oriolo

Linear optimal power flow (LOPF) algorithms use a linearization of the alternating current (AC) load flow equations to optimize generator dispatch in a network subject to the loading constraints of the network branches. Common algorithms…

Adaptation and Self-Organizing Systems · Physics 2018-02-01 Jonas Hörsch , Henrik Ronellenfitsch , Dirk Witthaut , Tom Brown

The identification of pipe roughnesses in a water distribution network is formulated as nonlinear system of algebraic equations which turns out to be demanding to solve under real-world circumstances. This paper proposes an enhanced…

Systems and Control · Electrical Eng. & Systems 2019-11-05 Stefan Kaltenbacher , Martin Steinberger , Martin Horn

Power flow calculation in EMS is required to accommodate a large and complex power system. To achieve a faster than real-time calculation, a graph based power flow calculation is proposed in this paper. Graph database and graph computing…

Signal Processing · Electrical Eng. & Systems 2018-11-07 Junjie Shi , Guangyi Liu , Renchang Dai , Jingjin Wu , Chen Yuan , Zhiwei Wang

Power flow calculations for systems with a large number of buses, e.g. grids with multiple voltage levels, or time series based calculations result in a high computational effort. A common power flow solver for the efficient analysis of…

Computation · Statistics 2018-04-19 Florian Schäfer , Martin Braun

Predicting the flow of non-Newtonian fluids in porous structure is still a challenging issue due to the interplay betwen the microscopic disorder and the non-linear rheology. In this letter, we study the case of an yield stress fluid in a…

Soft Condensed Matter · Physics 2019-06-26 Chen Liu , Andrea De Luca , Alberto Rosso , Laurent Talon

The multicommodity flow problem is a classic problem in network flow and combinatorial optimization, with applications in transportation, communication, logistics, and supply chain management, etc. Existing algorithms often focus on…

Data Structures and Algorithms · Computer Science 2023-04-25 Li Chen , Mingquan Ye

This paper develops a fixed-point iteration to solve the steady-state water flow equations in an urban water distribution network. The fixed-point iteration is derived upon the assumption of turbulent flow solutions and the validity of the…

Systems and Control · Computer Science 2018-07-05 Mohammadhafez Bazrafshan , Nikolaos Gatsis , Marcio Giacomoni , Ahmad Taha

In light of the increasing coupling between electricity and gas networks, this paper introduces two novel iterative methods for efficiently solving the multiperiod optimal electricity and gas flow (MOEGF) problem. The first is an iterative…

Optimization and Control · Mathematics 2021-06-28 Sleiman Mhanna , Isam Saedi , Pierluigi Mancarella

An iterative scheme is presented to solve analytically the relativistic fluid dynamics equations. The scheme is applied to longitudinal expansion, transversal symmetric and transversal asymmetric (triaxial) expansion as well. Within this…

High Energy Physics - Theory · Physics 2012-12-06 F. Wunderlich , B. Kämpfer

We extend the canonical problems of simulation and optimization of steady-state gas flows in pipeline networks with compressors to the transport of mixtures of highly heterogeneous gases injected throughout a network. Our study is motivated…

Optimization and Control · Mathematics 2022-12-05 Saif R. Kazi , Kaarthik Sundar , Shriram Srinivasan , Anatoly Zlotnik

In this paper a problem of stationary flow of generalized Newtonian fluid in a thin channel is considered. An efficient algorithm of solution is proposed that includes a flexible procedure for a continuous approximation of the apparent…

Fluid Dynamics · Physics 2020-08-18 Michal Wrobel

Understanding the feasible power flow region is of central importance to power system analysis. In this paper, we propose a geometric view of the power system loadability problem. By using rectangular coordinates for complex voltages, we…

Optimization and Control · Mathematics 2018-07-31 Y. Weng , R. Rajagopal , B. Zhang

A numerical framework for rigorous linear stability analysis of two-phase stratified flows of two immiscible fluids in horizontal circular pipes is presented. For the first time, three-dimensional disturbances, including those at the…

Fluid Dynamics · Physics 2023-07-17 Ilya Barmak , Alexander Gelfgat , Neima Brauner

Existing techniques for the cost optimization of water distribution networks either employ meta-heuristics, or try to develop problem-specific optimization techniques. Instead, we exploit recent advances in generic NLP solvers and explore a…

Systems and Control · Electrical Eng. & Systems 2021-11-24 Saumya Goyal , Om Damani , Ashutosh Mahajan

A computational study of three-dimensional instability of steady flows in a helical pipe of arbitrary curvature and torsion is carried out for the first time. The problem is formulated in Germano coordinates in two equivalent but different…

Fluid Dynamics · Physics 2019-08-29 Alexander Gelfgat

The recently proposed non-iterative load flow method, called the holomorphic embedding method, may encounter the precision issue, i.e. nontrivial round-off errors caused by the limit of digits used in computation when calculating the…

Systems and Control · Computer Science 2017-05-08 Bin Wang , Chengxi Liu , Kai Sun

In this work, we introduce an iterative linearised finite element method for the solution of Bingham fluid flow problems. The proposed algorithm has the favourable property that a subsequence of the sequence of iterates generated converges…

Numerical Analysis · Mathematics 2021-09-14 Pascal Heid , Endre Süli