Low Dynamics RLSL Adaptive Algorithm Using A Priori Estimation Errors

Author(s):  
C. Paleologu ◽  
S. Ciochina ◽  
A.A. Enescu
Author(s):  
Alexander Dmitrievich Baev ◽  
◽  
Dmitry Alexandrovich Chechin ◽  
Sergey Alexandrovich Shabrov ◽  
Natalya Ivanovna Rabotinskaya ◽  
...  

1996 ◽  
Author(s):  
Scott A. Sallberg ◽  
Byron M. Welsh ◽  
Michael C. Roggemann

2018 ◽  
Vol 132 (1) ◽  
pp. 81-96 ◽  
Author(s):  
Simon Rio ◽  
Tristan Mary-Huard ◽  
Laurence Moreau ◽  
Alain Charcosset

2020 ◽  
Vol 10 (23) ◽  
pp. 13382-13394 ◽  
Author(s):  
Toni Monleon‐Getino ◽  
Jorge Frias‐Lopez
Keyword(s):  
A Priori ◽  

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Ruyun Ma ◽  
Zhongzi Zhao

We study the local and global bifurcation of nonnegative nonconstant solutions of a discrete general Brusselator model. We generalize the linear u in the standard Brusselator model to the nonlinear fu. Assume that f∈C0,∞,0,∞ is a strictly increasing function, and f′f−1a∈0,∞. Taking b as the bifurcation parameter, we obtain that the solution set of the problem constitutes a constant solution curve and a nonconstant solution curve in a small neighborhood of the bifurcation point b0j,f−1a,ab/f−1a2. Moreover, via the Rabinowitz bifurcation theorem, we obtain the global structure of the set of nonconstant solutions under the condition that fs/s2 is nonincreasing in 0,∞. In this process, we also make a priori estimation for the nonnegative nonconstant solutions of the problem.


2017 ◽  
Vol 17 (1) ◽  
pp. 161-185 ◽  
Author(s):  
Mira Schedensack

AbstractThis paper generalizes the non-conforming FEM of Crouzeix and Raviart and its fundamental projection property by a novel mixed formulation for the Poisson problem based on the Helmholtz decomposition. The new formulation allows for ansatz spaces of arbitrary polynomial degree and its discretization coincides with the mentioned non-conforming FEM for the lowest polynomial degree. The discretization directly approximates the gradient of the solution instead of the solution itself. Besides the a priori and medius analysis, this paper proves optimal convergence rates for an adaptive algorithm for the new discretization. These are also demonstrated in numerical experiments. Furthermore, this paper focuses on extensions of this new scheme to quadrilateral meshes, mixed FEMs, and three space dimensions.


Author(s):  
Ayoub Gouasmi ◽  
Eric J. Parish ◽  
Karthik Duraisamy

Reduced models of nonlinear dynamical systems require closure, or the modelling of the unresolved modes. The Mori–Zwanzig procedure can be used to derive formally closed evolution equations for the resolved physics. In these equations, the unclosed terms are recast as a memory integral involving the time history of the resolved variables. While this procedure does not reduce the complexity of the original system, these equations can serve as a mathematically consistent basis to develop closures based on memory approximations. In this scenario, knowledge of the memory kernel is paramount in assessing the validity of a memory approximation. Unravelling the memory kernel requires solving the orthogonal dynamics, which is a high-dimensional partial differential equation that is intractable, in general. A method to estimate the memory kernel a priori , using full-order solution snapshots, is proposed. The key idea is to solve a pseudo orthogonal dynamics equation, which has a convenient Liouville form, instead. This ersatz arises from the assumption that the semi-group of the orthogonal dynamics is a composition operator for one observable. The method is exact for linear systems. Numerical results on the Burgers and Kuramoto–Sivashinsky equations demonstrate that the proposed technique can provide valuable information about the memory kernel.


Sign in / Sign up

Export Citation Format

Share Document