scholarly journals A concurrent two‐scale coupling for wave propagation using direct solution schemes with explicit time integration

Author(s):  
Christoph Grunwald ◽  
Nathanaël Durr ◽  
Martin Sauer ◽  
Werner Riedel ◽  
Stefan Hiermaier
2017 ◽  
Vol 09 (08) ◽  
pp. 1750115 ◽  
Author(s):  
W. B. Wen ◽  
S. Y. Duan ◽  
Y. Tao ◽  
Jun Liang ◽  
Daining Fang

An explicit time integration scheme for hyperbolic equations is proposed using B-spline interpolation and weighted residual method. It has simple formulation and calculation procedure. With one adjustable algorithmic parameter, new scheme has higher accuracy when compared with other excellent explicit schemes. New scheme has controllable and also desirable period elongation which is verified by theoretical analysis and numerical simulations. Especially, a demonstrative dispersion analysis coupled with the corresponding wave propagation demonstrate the desirable numerical dissipation property and the effectiveness of the proposed scheme for wave propagation problems.


2017 ◽  
Vol 50 (2) ◽  
pp. 77-96
Author(s):  
Juho Sormunen

One difficulty in the design of the load bearing components of mobile machines is the transient and non-linear nature of the loads acting on them. A common method for tracking these loads is to use strain gauges and force transducers on a physical test machine. An alternative method for determining the transient loads by means of a mathematical model that intends to describe the response of a John Deere 1010E forwarder as it crosses a test track is utilized in this study. The model is based on finite element method and it is solved using explicit time integration and LS-DYNA® software. As a result of this study a model capable of replicating the real world with a reasonable accuracy was obtained. The forces acting on tires, which can be considered the most important results of this work, can be used as boundary conditions in consequent analyses, such as fatigue simulation.


2021 ◽  
Vol 2090 (1) ◽  
pp. 012145
Author(s):  
Ryuma Honda ◽  
Hiroki Suzuki ◽  
Shinsuke Mochizuki

Abstract This study presents the impact of the difference between the implicit and explicit time integration methods on a steady turbulent flow field. In contrast to the explicit time integration method, the implicit time integration method may produce significant kinetic energy conservation error because the widely used spatial difference method for discretizing the governing equations is explicit with respect to time. In this study, the second-order Crank-Nicolson method is used as the implicit time integration method, and the fourth-order Runge-Kutta, second-order Runge-Kutta and second-order Adams-Bashforth methods are used as explicit time integration methods. In the present study, both isotropic and anisotropic steady turbulent fields are analyzed with two values of the Reynolds number. The turbulent kinetic energy in the steady turbulent field is hardly affected by the kinetic energy conservation error. The rms values of static pressure fluctuation are significantly sensitive to the kinetic energy conservation error. These results are examined by varying the time increment value. These results are also discussed by visualizing the large scale turbulent vortex structure.


1986 ◽  
Vol 65 (2) ◽  
pp. 253-272 ◽  
Author(s):  
L. Garcia ◽  
H.R. Hicks ◽  
B.A. Carreras ◽  
L.A. Charlton ◽  
J.A. Holmes

Author(s):  
Ryuta Imai ◽  
Naoki Kasui ◽  
Masayuki Yamada ◽  
Koji Hada ◽  
Hiroyuki Fujiwara

In this paper, we propose a smoothing scheme for seismic wave propagation simulation. The proposed scheme is based on a diffusionized wave equation with the fourth-order spatial derivative term. So, the solution requires higher regularity in the usual weak formulation. Reducing the diffusionized wave equation to a coupled system of diffusion equations yields a mixed FEM to ease the regularity. We mathematically explain how our scheme works for smoothing. We construct a semi-implicit time integration scheme and apply it to the wave equation. This numerical experiment reveals that our scheme is effective for filtering short wavelength components in seismic wave propagation simulation.


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