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Svetlana V. Poroseva

Publications and source records attributed to Svetlana V. Poroseva.

5 recordsLinked to original sources

"Selfish" algorithm for optimizing the network survivability analysis

In Nature, the primary goal of any network is to survive. This is less obvious for engineering networks (electric power, gas, water, transportation systems etc.) that are expected to operate under normal conditions most of time. As a result, the ability of a network to withstand massive sudden damage caused by adverse events (or survivability) has not been among traditional goals in the network design. Reality, however, calls for the adjustment of design priorities. As modern networks develop toward increasing their size, complexity, and integration, the likelihood of adverse events increases too due to technological development, climate change, and activities in the political arena among other factors. Under such circumstances, a network failure has an unprecedented effect on lives and economy. To mitigate the impact of adverse events on the network operability, the survivability analysis must be conducted at the early stage of the network design. Such analysis requires the development of new analytical and computational tools. Computational analysis of the network survivability is the exponential time problem at least. The current paper describes a new algorithm, in which the reduction of the computational complexity is achieved by mapping an initial network topology with multiple sources and sinks onto a set of simpler smaller topologies with multiple sources and a single sink. Steps for further reducing the time and space expenses of computations are also discussed.

physics.soc-ph↗

Floridian high-voltage power-grid network partitioning and cluster optimization using simulated annealing

Many partitioning methods may be used to partition a network into smaller clusters while minimizing the number of cuts needed. However, other considerations must also be taken into account when a network represents a real system such as a power grid. In this paper we use a simulated annealing Monte Carlo (MC) method to optimize initial clusters on the Florida high-voltage power-grid network that were formed by associating each load with its "closest" generator. The clusters are optimized to maximize internal connectivity within the individual clusters and minimize the power deficiency or surplus that clusters may otherwise have.

physics.soc-ph↗

Spectral matrix methods for partitioning power grids: Applications to the Italian and Floridian high-voltage networks

Intentional islanding is used to limit cascading power failures by isolating highly connected "islands" with local generating capacity. To efficiently isolate an island, one should break as few power lines as possible. This is a graph partitioning problem, and here we give preliminary results on islanding of the Italian and Floridian high-voltage grids by spectral matrix methods.

physics.soc-ph↗

Validation of a new k-epsilon model with the pressure diffusion effects in separated flows

The contribution of the "rapid" part of the pressure diffusion to the turbulent kinetic energy balance is analyzed, and a new model to describe its effect is suggested. A new transport equation for the turbulent kinetic energy is derived. The new k-equation does not require any modification in the standard epsilon-equation. A new k-epsilon model, which includes the new k-equation and the standard epsilon-equation, is validated in four separated flows: a planar diffuser, over a backstep, in a channel with wavy walls, and in an axisymmetric combustion chamber. It is shown that a new model reproduces the mean velocity, shear stress, and turbulent kinetic energy profiles and the skin friction coefficient in very good agreement with experimental data.

physics.flu-dyn↗

Modeling the "rapid" part of the velocity/pressure-gradient correlation in inhomogeneous turbulent flows

A new model for the "rapid" part of the velocity/pressure-gradient correlation in the Reynolds averaged Navier-Stokes equations is suggested. It is shown that in an inhomogeneous incompressible turbulent flow, the model that is linear in the Reynolds stresses should include two model coefficients. A functional form of the coefficients is analyzed in some extreme turbulence states. As demonstrated, the proposed model reduces to the standard linear pressure-strain model in homogeneous turbulence and can satisfy realizability conditions provided the coefficients are functions of the mean velocity gradients and the Reynolds stresses. In an inhomogeneous turbulent flow, coefficients should depend on parameters directly related to inhomogeneous effects. The model is validated using direct numerical simulation data from two flows: the plane wake and the plane mixing layer.

physics.flu-dyn↗