Numerical calculations of elastic modes frequencies for parametric oscillatory instability in Advanced LIGO interferometer

2008 ◽  
Vol 372 (35) ◽  
pp. 5727-5731 ◽  
Author(s):  
S.E. Strigin ◽  
D.G. Blair ◽  
S. Gras ◽  
S.P. Vyatchanin
Keyword(s):  
Oscillatory Instability ◽  
Numerical Calculations ◽  
Elastic Modes

COMPARISON BETWEEN EXPERIMENTS AND NUMERICAL CALCULATIONS ON S = 1/2 HEISENBERG-XY FERROMAGNETIC CHAINS

1988 ◽  
Vol 49 (C8) ◽  
pp. C8-1451-C8-1452 ◽  
Author(s):  
K. Kopinga ◽  
J. Emmen ◽  
G. C. de Vries ◽  
L. F. Lemmens ◽  
G. Kamieniarz
Keyword(s):  
Numerical Calculations

The Feasibility of Numerical Calculations of Vias Using the Matrix-Penciled Moment Method

PIERS Online ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 36-40 ◽  
Author(s):  
Hailiang Li ◽  
Yu Tian ◽  
Tong Ling
Keyword(s):  
Moment Method ◽  
Numerical Calculations ◽  
The Matrix

Normal form method in search for periodic solutions of ordinary differential equations. Case of the fourth order

2018 ◽  
pp. 24-34
Author(s):  
V. F. Edneral ◽  
O. D. Timofeevskaya
Keyword(s):  
Normal Form ◽  
Differential Equations ◽  
Ordinary Differential Equations ◽  
Periodic Solutions ◽  
Fourth Order ◽  
Numerical Solutions ◽  
Numerical Calculations ◽  
Computational Time ◽  
Resonant Normal Form ◽  
Normal Form Method

Introduction:The method of resonant normal form is based on reducing a system of nonlinear ordinary differential equations to a simpler form, easier to explore. Moreover, for a number of autonomous nonlinear problems, it is possible to obtain explicit formulas which approximate numerical calculations of families of their periodic solutions. Replacing numerical calculations with their precalculated formulas leads to significant savings in computational time. Similar calculations were made earlier, but their accuracy was insufficient, and their complexity was very high.Purpose:Application of the resonant normal form method and a software package developed for these purposes to fourth-order systems in order to increase the calculation speed.Results:It has been shown that with the help of a single algorithm it is possible to study equations of high orders (4th and higher). Comparing the tabulation of the obtained formulas with the numerical solutions of the corresponding equations shows good quantitative agreement. Moreover, the speed of calculation by prepared approximating formulas is orders of magnitude greater than the numerical calculation speed. The obtained approximations can also be successfully applied to unstable solutions. For example, in the Henon — Heyles system, periodic solutions are surrounded by chaotic solutions and, when numerically integrated, the algorithms are often unstable on them.Practical relevance:The developed approach can be used in the simulation of physical and biological systems.

scholarly journals Experimental and CFD Simulations of the Aerosol Flow in the Air Ventilating the Underground Excavation in Terms of SARS-CoV-2 Transmission

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4743
Author(s):  
Tomasz Janoszek ◽  
Zbigniew Lubosik ◽  
Lucjan Świerczek ◽  
Andrzej Walentek ◽  
Jerzy Jaroszewicz
Keyword(s):  
Numerical Calculations ◽  
Mining Institute ◽  
Ventilation Network ◽  
Underground Excavation ◽  
In Situ Tests ◽  
Ansys Fluent ◽  
Aerosol Emission ◽  
Ansys Cfx ◽  
Computational Fluid Dynamics Cfd

The paper presents the results of experimental and model tests of transport of dispersed fluid droplets forming a cloud of aerosol in a stream of air ventilating a selected section of the underground excavation. The excavation selected for testing is part of the ventilation network of the Experimental Mine Barbara of the Central Mining Institute. For given environmental conditions, such as temperature, pressure, relative humidity, and velocity of air, the distribution of aerosol droplet changes in the mixture of air and water vapor along the excavation at a distance was measured at 10 m, 25 m, and 50 m from the source of its emission. The source of aerosol emission in the excavation space was a water nozzle that was located 25 m from the inlet (inlet) of the excavation. The obtained results of in situ tests were related to the results of numerical calculations using computational fluid dynamics (CFD). Numerical calculations were performed using Ansys-Fluent and Ansys-CFX software. The dimensions and geometry of the excavation under investigation are presented. The authors describe the adopted assumptions and conditions for the numerical model and discuss the results of the numerical solution.

Terahertz response of dl-alanine: experiment and theory

2021 ◽  
Vol 23 (1) ◽  
pp. 657-665
Author(s):  
T. J. Sanders ◽  
J. L. Allen ◽  
J. Horvat ◽  
R. A. Lewis
Keyword(s):  
Large Scale ◽  
Numerical Calculations ◽  
Molecular Vibrations

Numerical calculations and experiments have identified large-scale molecular vibrations leading to unique terahertz spectral absorptions observed in dl-alanine.

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