scholarly journals Numerical scheme for the far-out-of-equilibrium time-dependent Boltzmann collision operator: 1D second-degree momentum discretisation and adaptive time stepping

2021 ◽  
Vol 263 ◽  
pp. 107863
Author(s):  
I. Wadgaonkar ◽  
R. Jain ◽  
M. Battiato
Keyword(s):  
Numerical Scheme ◽  
Collision Operator ◽  
Time Dependent ◽  
Equilibrium Time ◽  
Time Stepping ◽  
Adaptive Time ◽  
Boltzmann Collision Operator ◽  
Adaptive Time Stepping ◽  
Second Degree

Fast Conjugate Heat Transfer Simulation of Long Transient Flexible Operations Using Adaptive Time Stepping

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
R. Maffulli ◽  
L. He ◽  
P. Stein ◽  
G. Marinescu
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Time Derivative ◽  
Computational Cost ◽  
Strong Impact ◽  
Time Step ◽  
Time Stepping ◽  
Adaptive Time ◽  
Fully Coupled ◽  
Adaptive Time Stepping

The emerging renewable energy market calls for more advanced prediction tools for turbine transient operations in fast startup/shutdown cycles. Reliable numerical analysis of such transient cycles is complicated by the disparity in time scales of the thermal responses in fluid and solid domains. Obtaining fully coupled time-accurate unsteady conjugate heat transfer (CHT) results under these conditions would require to march in both domains using the time-step dictated by the fluid domain: typically, several orders of magnitude smaller than the one required by the solid. This requirement has strong impact on the computational cost of the simulation as well as being potentially detrimental to the accuracy of the solution due to accumulation of round-off errors in the solid. A novel loosely coupled CHT methodology has been recently proposed, and successfully applied to both natural and forced convection cases that remove these requirements through a source-term based modeling (STM) approach of the physical time derivative terms in the relevant equations. The method has been shown to be numerically stable for very large time steps with adequate accuracy. The present effort is aimed at further exploiting the potential of the methodology through a new adaptive time stepping approach. The proposed method allows for automatic time-step adjustment based on estimating the magnitude of the truncation error of the time discretization. The developed automatic time stepping strategy is applied to natural convection cases under long (2000 s) transients: relevant to the prediction of turbine thermal loads during fast startups/shutdowns. The results of the method are compared with fully coupled unsteady simulations showing comparable accuracy with a significant reduction of the computational costs.

scholarly journals An error-controlled adaptive time-stepping method for particle advancement in coupled CFD-DEM simulations

2021 ◽  
Vol 379 ◽  
pp. 203-216
Author(s):  
Hariswaran Sitaraman ◽  
Deepthi Vaidhynathan ◽  
Ray Grout ◽  
Thomas Hauser ◽  
Christine M. Hrenya ◽  
...  
Keyword(s):  
Time Stepping ◽  
Dem Simulations ◽  
Adaptive Time ◽  
Adaptive Time Stepping

An Adaptive Time Stepping Method for Transient Dynamic Response Analysis

2016 ◽  
Vol 6 (2) ◽  
pp. 152-170
Author(s):  
Jianguo Huang ◽  
Huashan Sheng
Keyword(s):  
Dynamic Response ◽  
Response Analysis ◽  
Dynamic Response Analysis ◽  
Transient Dynamic ◽  
Time Stepping ◽  
Adaptive Time ◽  
Spatial Discretisation ◽  
Transient Dynamic Response ◽  
Adaptive Time Stepping ◽  
Reduced Problem

AbstractAn efficient adaptive time stepping method is proposed for transient dynamic response analysis, which is frequently encountered in civil engineering and elsewhere. The reduced problem following the spatial discretisation can be discretised in the time by a C0-continuous discontinuous Galerkin method, and the adaptive time stepping strategy is based on optimal a posteriori error estimates developed using the energy method. Some numerical experiments demonstrate the effectiveness of our approach.

Adaptive time-stepping algorithms for molecular beam epitaxy: Based on energy or roughness

2020 ◽  
Vol 99 ◽  
pp. 105991
Author(s):  
Fusheng Luo ◽  
Hehu Xie ◽  
Manting Xie ◽  
Fei Xu
Keyword(s):  
Molecular Beam Epitaxy ◽  
Molecular Beam ◽  
Time Stepping ◽  
Adaptive Time ◽  
Adaptive Time Stepping

Stochastic dynamics of a nonlinear time-varying spur gear model using an adaptive time-stepping path integration method

2019 ◽  
Vol 447 ◽  
pp. 170-185
Author(s):  
Saeed Gheisari Hasnijeh ◽  
Mehrdad Poursina ◽  
Bernt Johan Leira ◽  
Hossein Karimpour ◽  
Wei Chai
Keyword(s):  
Path Integration ◽  
Stochastic Dynamics ◽  
Integration Method ◽  
Spur Gear ◽  
Time Varying ◽  
Time Stepping ◽  
Path Integration Method ◽  
Adaptive Time ◽  
Adaptive Time Stepping
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