A Green's function approach to deriving non-reflecting boundary conditions in molecular dynamics simulations

2005 ◽  
Vol 62 (9) ◽  
pp. 1250-1262 ◽  
Author(s):  
E. G. Karpov ◽  
G. J. Wagner ◽  
Wing Kam Liu
Keyword(s):  
Molecular Dynamics ◽  
Boundary Conditions ◽  
Green’S Function ◽  
Molecular Dynamics Simulations ◽  
Green's Function ◽  
Function Approach ◽  
Dynamics Simulations

scholarly journals Analysis of the interaction of thermoacoustic modes with a Green’s function approach

2018 ◽  
Vol 10 (4) ◽  
pp. 326-336 ◽  
Author(s):  
Alessandra Bigongiari ◽  
Maria Heckl
Keyword(s):  
Green’S Function ◽  
Green's Function ◽  
Initial Perturbation ◽  
Time History ◽  
Function Approach ◽  
Stability Maps ◽  
Flame Describing Function ◽  
The Stability ◽  
Dynamics Simulations ◽  
Fast Prediction

In this paper, we will present a fast prediction tool based on a one-dimensional Green's function approach that can be used to bypass numerically expensive computational fluid dynamics simulations. The Green’s function approach has the advantage of providing a clear picture of the physics behind the generation and evolution of combustion instabilities. In addition, the method allows us to perform a modal analysis; single acoustic modes can be treated in isolation or in combination with other modes. In this article, we will investigate the role of higher-order modes in determining the stability of the system. We will initially produce the stability maps for the first and second mode separately. Then the time history of the perturbation will be computed, where both the modes are present. The flame will be modelled by a generic Flame Describing Function, i.e. by an amplitude-dependent Flame Transfer Function. The time-history calculations show the evolution of the two modes resulting from an initial perturbation; both transient and limit-cycle oscillations are revealed. Our study represents a first step towards the modelling of nonlinearity and non-normality in combustion processes.

Vibration of Single- and Double-Layered Graphene Sheets

2011 ◽  
Vol 2 (1) ◽  
Author(s):  
Behrouz Arash ◽  
Quan Wang
Keyword(s):  
Molecular Dynamics ◽  
Boundary Conditions ◽  
Molecular Dynamics Simulations ◽  
Nonlocal Parameter ◽  
Small Scale ◽  
Graphene Sheets ◽  
Elastic Model ◽  
Resonant Frequencies ◽  
Nonlocal Continuum Theory ◽  
Dynamics Simulations

Free vibration of single- and double-layered graphene sheets is investigated by employing nonlocal continuum theory and molecular dynamics simulations. Results show that the classical elastic model overestimated the resonant frequencies of the sheets by a percentage as high as 62%. The dependence of small-scale effects, sizes of sheets, boundary conditions, and number of layers on vibrational characteristic of single- and double-layered graphene sheets is studied. The resonant frequencies predicted by the nonlocal elastic plate theory are verified by the molecular dynamics simulations, and the nonlocal parameter is calibrated through the verification process. The simulation results reveal that the calibrated nonlocal parameter depends on boundary conditions and vibrational modes. The nonlocal plate model is found to be indispensable in vibration analysis of grapheme sheets with a length less than 8 nm on their sides.

Combining molecular dynamics with mesoscopic Green’s function reaction dynamics simulations

2015 ◽  
Vol 143 (21) ◽  
pp. 214102 ◽  
Author(s):  
Adithya Vijaykumar ◽  
Peter G. Bolhuis ◽  
Pieter Rein ten Wolde
Keyword(s):  
Molecular Dynamics ◽  
Green’S Function ◽  
Green's Function ◽  
Reaction Dynamics ◽  
Dynamics Simulations

scholarly journals On the Vibration of Single-Walled Carbon Nanocones: Molecular Mechanics Approach versus Molecular Dynamics Simulations

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
R. Ansari ◽  
A. Momen ◽  
S. Rouhi ◽  
S. Ajori
Keyword(s):  
Molecular Dynamics ◽  
Boundary Conditions ◽  
Molecular Dynamics Simulations ◽  
Natural Frequency ◽  
Structural Method ◽  
Covalent Bonds ◽  
Carbon Nanocones ◽  
Single Walled Carbon ◽  
Vibrational Behavior ◽  
Dynamics Simulations

The vibrational behavior of single-walled carbon nanocones is studied using molecular structural method and molecular dynamics simulations. In molecular structural approach, point mass and beam elements are employed to model the carbon atoms and the connecting covalent bonds, respectively. Single-walled carbon nanocones with different apex angles are considered. Besides, the vibrational behavior of nanocones under various types of boundary conditions is studied. Predicted natural frequencies are compared with the existing results in the literature and also with the ones obtained by molecular dynamics simulations. It is found that decreasing apex angle and the length of carbon nanocone results in an increase in the natural frequency. Comparing the vibrational behavior of single-walled carbon nanocones under different boundary conditions shows that the effect of end condition on the natural frequency is more prominent for nanocones with smaller apex angles.

scholarly journals Nonperiodic stochastic boundary conditions for molecular dynamics simulations of materials embedded into a continuum mechanics domain

2011 ◽  
Vol 134 (15) ◽  
pp. 154108 ◽  
Author(s):  
Mohammad Rahimi ◽  
Hossein Ali Karimi-Varzaneh ◽  
Michael C. Böhm ◽  
Florian Müller-Plathe ◽  
Sebastian Pfaller ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Boundary Conditions ◽  
Molecular Dynamics Simulations ◽  
Continuum Mechanics ◽  
Dynamics Simulations ◽  
Stochastic Boundary
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