A fully implicit scheme for simulating ionized gas flows using the gas dynamics electrodynamics coupled system

2014 ◽  
Vol 76 (11) ◽  
pp. 909-937 ◽  
Author(s):  
Konstantinos T. Panourgias ◽  
John A. Ekaterinaris
Keyword(s):  
Gas Dynamics ◽  
Coupled System ◽  
Implicit Scheme ◽  
Gas Flows ◽  
Ionized Gas ◽  
Fully Implicit

scholarly journals A Fully Implicit Finite Volume Scheme for a Seawater Intrusion Problem in Coastal Aquifers

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1639
Author(s):  
Abdelkrim Aharmouch ◽  
Brahim Amaziane ◽  
Mustapha El Ossmani ◽  
Khadija Talali
Keyword(s):  
Finite Volume ◽  
Coastal Aquifers ◽  
Nonlinear Partial Differential Equations ◽  
Time Integration ◽  
Mass Conservation ◽  
Coupled System ◽  
Finite Volume Scheme ◽  
Time Step ◽  
Volume Scheme ◽  
Fully Implicit

We present a numerical framework for efficiently simulating seawater flow in coastal aquifers using a finite volume method. The mathematical model consists of coupled and nonlinear partial differential equations. Difficulties arise from the nonlinear structure of the system and the complexity of natural fields, which results in complex aquifer geometries and heterogeneity in the hydraulic parameters. When numerically solving such a model, due to the mentioned feature, attempts to explicitly perform the time integration result in an excessively restricted stability condition on time step. An implicit method, which calculates the flow dynamics at each time step, is needed to overcome the stability problem of the time integration and mass conservation. A fully implicit finite volume scheme is developed to discretize the coupled system that allows the use of much longer time steps than explicit schemes. We have developed and implemented this scheme in a new module in the context of the open source platform DuMu X . The accuracy and effectiveness of this new module are demonstrated through numerical investigation for simulating the displacement of the sharp interface between saltwater and freshwater in groundwater flow. Lastly, numerical results of a realistic test case are presented to prove the efficiency and the performance of the method.

scholarly journals Fully Implicit Stress Update Algorithm for Distortion−Based Anisotropic Hardening with Cross−Loading Effect: Comparative Algorithmic Study and Application to Large−Size Forming Problem

2021 ◽  
Vol 11 (12) ◽  
pp. 5509
Author(s):  
Hongjin Choi ◽  
Seonghwan Choi ◽  
Soo-Chang Kang ◽  
Myoung-Gyu Lee
Keyword(s):  
Predictive Accuracy ◽  
Large Strain ◽  
Implicit Scheme ◽  
Loading Path ◽  
Plastic State ◽  
Loading Conditions ◽  
Integration Algorithm ◽  
Implicit Algorithm ◽  
Fully Implicit ◽  
Large Size

A fully implicit stress integration algorithm is developed for the distortional hardening model, namely the e−HAH model, capable of simulating cross−hardening/softening under orthogonal loading path changes. The implicit algorithm solves a complete set of residuals as nonlinear functions of stress, a microstructure deviator, and plastic state variables of the constitutive model, and provides a consistent tangent modulus. The number of residuals is set to be 20 or 14 for the continuum or shell elements, respectively. Comprehensive comparison programs are presented regarding the predictive accuracy and stability with different numerical algorithms, strain increments, material properties, and loading conditions. The flow stress and r−value evolutions under reverse/cross−loading conditions prove that the algorithm is robust and accurate, even with large strain increments. By contrast, the cutting−plane method and partially implicit Euler backward method, which are characterized by a reduced number of residuals, result in unstable responses under abrupt loading path changes. Finally, the algorithm is implemented into the finite element modeling of large−size, S−rail forming and the springback for two automotive steel sheets, which is often solved by a hybrid dynamic explicit–implicit scheme. The fully implicit algorithm performs well for the whole simulation with the solely static implicit scheme.

Gas dynamics and star formation in “isolated” and interacting galaxies using FP observations

2019 ◽  
Vol 14 (S353) ◽  
pp. 264-265
Author(s):  
Isaura Fuentes-Carrera ◽  
Nelli Cárdenas-Martínez ◽  
Martín Nava-Callejas ◽  
Margarita Rosado
Keyword(s):  
Star Formation ◽  
Gas Dynamics ◽  
Equal Mass ◽  
Interacting Galaxies ◽  
Ionized Gas ◽  
Star Forming ◽  
Gas Kinematics ◽  
Fabry Perot ◽  
Different Types

AbstractWe present scanning Fabry-Perot observations of different types of star-forming galaxies from apparently isolated LIRGs to equal mass interacting galaxies. We analyze the ionized gas kinematics, its relation with the morphology of each system and the location of SF regions for different systems.

Near infrared spectroscopy of protostars

1981 ◽  
Vol 303 (1480) ◽  
pp. 487-496
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Gas Dynamics ◽  
Near Infrared ◽  
Molecular Gas ◽  
Orion Nebula ◽  
Ionized Gas ◽  
Physical Conditions ◽  
Vibrational Bands ◽  
Optical Wavelengths

Observational study of protostars and their immediate environs has recently become possible as a result of advances in infrared spectroscopy, especially in the near infrared (A = 2—5 pm). Although such stars are totally obscured at optical wavelengths by the enshrouding dust and gas from which they formed, the near infrared spectroscopy has yielded detection of emission lines from both ionized gas and high excitation molecular gas ( T >2000 K) probably within a few astronomical units of several such sources (e.g. the BN object in the Orion nebula). The former lines provide the first constraints on the spectral type and temperature of the protostar; the latter reveal the physical conditions (density and temperature) and gas dynamics in the immediate protostellar nebula. . Data on the BN object covering the CO, 13 CO, and H 2 vibrational bands and the H II lines are presented as an illustration of these techniques.

scholarly journals A system of ionized gas dynamics

2019 ◽  
Vol 60 (11) ◽  
pp. 111507 ◽  
Author(s):  
Fumioki Asakura ◽  
Andrea Corli
Keyword(s):  
Gas Dynamics ◽  
Ionized Gas

scholarly journals The Mass Distribution in the Central Few Parsecs of the Galaxy

1989 ◽  
Vol 136 ◽  
pp. 493-499
Author(s):  
John H. Lacy
Keyword(s):  
Mass Distribution ◽  
Gas Dynamics ◽  
Good Evidence ◽  
Ionized Gas ◽  
Massive Black Hole ◽  
Central Mass ◽  
Magnetic Forces ◽  
Gravitational Forces ◽  
The Galaxy

The determination of the mass distribution in the central few parsecs of the Galaxy, primarily from the ionized gas dynamics, is discussed. The gas motions are described and interpreted assuming that the orbits are determined by gravitational forces. It is shown that there is good evidence for a central mass of ~ 2 × 106 M⊙. The primary uncertainty in this conclusion results from the possibility of significant magnetic forces. In the absence of corroborating evidence, the case for a massive black hole cannot be considered proven.

scholarly journals Modeling of Ionized Gas Flows with a Velocity-space Hybrid Boltzmann Solver

2021 ◽  
Author(s):  
Georgii Oblapenko ◽  
David B. Goldstein ◽  
Philip Varghese ◽  
Christopher Moore
Keyword(s):  
Velocity Space ◽  
Gas Flows ◽  
Ionized Gas

scholarly journals An enhanced sequential fully implicit scheme for reservoir geomechanics

2020 ◽  
Vol 24 (4) ◽  
pp. 1557-1587
Author(s):  
Omar Duran ◽  
Manouchehr Sanei ◽  
Philippe R. B. Devloo ◽  
Erick S. R. Santos
Keyword(s):  
Implicit Scheme ◽  
Fully Implicit ◽  
Reservoir Geomechanics
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