https://puma.ub.uni-stuttgart.de/group/simtech/VariationalPUMA RSS feed for /group/simtech/Variational2026-04-22T08:58:23+02:00https://puma.ub.uni-stuttgart.de/bibtex/2c3e01e05c13c7df1767d793cd87277a1/mhartmannmhartmann2018-07-20T10:54:15+02:00Ferroelectric of maximum Variational Principle dissipation hysteresis, vorlaeufig inequality, <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Michael Kutter" itemprop="url" href="/person/172ee6ff7de36af3e9f85cfc93853cfb8/author/0"><span itemprop="name">M. Kutter</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Anna-Margarete Sändig" itemprop="url" href="/person/172ee6ff7de36af3e9f85cfc93853cfb8/author/1"><span itemprop="name">A. Sändig</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">GAMM-Mitteilungen</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">34 </span></span>(<span itemprop="issueNumber">1</span>): <span itemprop="pagination">84--89</span></em> </span>(<em><span>2011<meta content="2011" itemprop="datePublished"/></span></em>)</span>Fri Jul 20 10:54:15 CEST 2018GAMM-Mitteilungen184--89Modeling of ferroelectric hysteresis as variational inequality342011Ferroelectric of maximum Variational Principle dissipation hysteresis, vorlaeufig inequality, Ferroelectric materials are characterized by interaction-effects of mechanical and electrical fields due to different polarization directions of the unit cells. The relations between polarisation and electric field and mechanical strain and electric field respectively can be described by hysteresis curves. Some models, which describe the ferroelectric material behaviour, e.g. [3], [8], rely on concepts close to elastoplasticity. We use these ideas and derive variational evolution inequalities analogously to elastoplastic models discussed in [1]. Based on these inequalities we formulate equivalent mathematical problems and get some existence results. The formulation of variational evolution inequalities is a good starting point for numerical methods similar to elastoplasticity (� 2011 WILEY-VCH Verlag GmbH \& Co. KGaA, Weinheim)https://puma.ub.uni-stuttgart.de/bibtex/25a0f256fc25c38578d18cb42bbc16073/hermannhermann2017-05-18T11:32:12+02:00Collocation} De-aliasing; Large Stability; method; {Discontinuous simulation; Smagorinsky Galerkin; Variational model; eddy multiscale <span data-person-type="author" class="authorEditorList "><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Andrea D. Beck" itemprop="url" href="/person/1cd5d1b10b22291c542ef46b9992e123d/author/0"><span itemprop="name">A. Beck</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="David G. Flad" itemprop="url" href="/person/1cd5d1b10b22291c542ef46b9992e123d/author/1"><span itemprop="name">D. Flad</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Claudia Tonhaeuser" itemprop="url" href="/person/1cd5d1b10b22291c542ef46b9992e123d/author/2"><span itemprop="name">C. Tonhaeuser</span></a></span>, </span><span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Gregor Gassner" itemprop="url" href="/person/1cd5d1b10b22291c542ef46b9992e123d/author/3"><span itemprop="name">G. Gassner</span></a></span>, </span> and <span><span itemtype="http://schema.org/Person" itemscope="itemscope" itemprop="author"><a title="Claus-Dieter Munz" itemprop="url" href="/person/1cd5d1b10b22291c542ef46b9992e123d/author/4"><span itemprop="name">C. Munz</span></a></span></span>. </span><span class="additional-entrytype-information"><span itemtype="http://schema.org/PublicationIssue" itemscope="itemscope" itemprop="isPartOf"><em><span itemprop="journal">FLOW TURBULENCE AND COMBUSTION</span>, </em> <em><span itemtype="http://schema.org/PublicationVolume" itemscope="itemscope" itemprop="isPartOf"><span itemprop="volumeNumber">97 </span></span>(<span itemprop="issueNumber">2</span>): <span itemprop="pagination">475-511</span></em> </span>(<em><span>September 2016<meta content="September 2016" itemprop="datePublished"/></span></em>)</span>Thu May 18 11:32:12 CEST 2017{VAN GODEWIJCKSTRAAT 30, 3311 GZ DORDRECHT, NETHERLANDS}{FLOW TURBULENCE AND COMBUSTION}{SEP}{2}{475-511}{On the Influence of Polynomial De-aliasing on Subgrid Scale Models}{Article}{97}{2016}Collocation} De-aliasing; Large Stability; method; {Discontinuous simulation; Smagorinsky Galerkin; Variational model; eddy multiscale {In this work we investigate the interplay of polynomial de-aliasing and sub-grid scale models for large eddy simulations based on discontinuous Galerkin discretizations. It is known that stability is a major concern when simulating underresolved turbulent flows with high order nodal collocation type discretizations. By changing the interpolatory character of the nodal collocation type discretization to a projection based discretization by increasing the number of quadrature points (polynomial de-aliasing), one is able to remove the aliasing induced stability problems. We focus on this effect and on the consequence for large eddy simulations with explicit subgrid scale models. Often, subgrid scale models have to achieve two possibly conflicting tasks in a single simulation: firstly stabilizing the numerics and secondly modeling the physical effect of the missing scales. Within a discontinuous Galerkin approach, it is possible to use either a fast (but potentially aliasing afflicted) nodal collocation discretization or a projection-based (but computationally costly) variant in combination with an explicit subgrid scale model. We use this framework to investigate the effect on the appropriate model parameter of a standard Smagorinsky subgrid scale model and of a Variational Multiscale Smagorinsky formulation. For this we first consider the 3-D viscous Taylor-Green vortex example to investigate the impact on the stability of the method and second the turbulent flow past a circular cylinder to investigate and compare the accuracy of the results. We show that the aliasing instabilities of collocative discretizations severely limit the choice of the model constant, in particular for high order schemes, while for de-aliased DG schemes, the closure model parameters can be chosen independently from the numerical scheme. For the cylinder flow, we also find that for the same model settings, the projection-based results are in better agreement with the reference DNS than those of the collocative scheme.}