COMSOL Exchange
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Receive updates on user-generated models in COMSOL ExchangeThu, 18 Dec 2014 12:18:21 +0000COMSOL Exchangehttp://www.comsol.com/shared/images/logos/comsol_logo.gif
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3D fiber coupler
http://feedproxy.google.com/~r/ComsolExchange/~3/SrY201Eo9Y8/
Optical fiber coupler, based on the tutorial "Directional Coupler" using the Wave Optics module.<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/SrY201Eo9Y8" height="1" width="1" alt=""/>Thu, 18 Dec 2014 12:18:21 +00003.1418905101.251http://www.comsol.com/community/exchange/251/Plasmaline & Plasmaline-NG (microwave SWP and MVP)
http://feedproxy.google.com/~r/ComsolExchange/~3/hyat4I5264A/
* 2Daxisym-plasm... is a model of the so-called Plasmaline (E. Raeuchle, http://jp4.journaldephysique.org/articles/jp4/pdf/1998/07/jp4199808PR708.pdf)<br />
it is running a 70 Pa Argon at 500W and 2,45GHz but only on a single side input.<br />
* finger-upload is the single sided version.<br />
* basic-mwp-lineNG is the a version of the plasmaline invented here in Nagoya (MVP here, or Plasmaline NextGeneration for me) which omits the quartz tube but therefore need a DC-sheath space. (it shows the expected behaviour but the chemistry has no metastables)<br />
*MVP17 is my last model. It is converging within 1hr.40minutes with mesh2, you can find out steady-state by monitoring the Timeplot. It needs the right mobility values to get closer to reality and the sputtering effects.(may be not always converging.. sometimes the ion concentration makes problems if not some runaway of e-temperature)<br />
<br />
The models do not reproduce reality. Depending on which rate constant description I rely on, the power loss structure is very different (xsec-tables or townsend look-up). <br />
I need help on setting the right chemistry and mobilities..<br />
What is also missing is the sputtering effects of the DC voltage.<br />
The plasma color is definitively not the color of a pure Argon plasma but a lot of metal ions are present (10E15 to my extrapolation).<br />
<br />
need to solve the BE for giving the models the right mobility coefficients..<br />
looking for co-authors for a journal paper.<br />
<br />
one big open question is still the resonance effects of the electric field at the cutoff plasma density . I included the doppler broadening parameter used for the ECR case (an erf function on Efield value), but I have no plan how to calibrate it.<br />
<br />
what is a good value for secondary emission coefficient of Cu cathode material?<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/hyat4I5264A" height="1" width="1" alt=""/>Fri, 24 Oct 2014 01:11:58 +00003.1414113118.213http://www.comsol.com/community/exchange/213/Computation of Antenna Radiating Near-Fields
http://feedproxy.google.com/~r/ComsolExchange/~3/K4XT-hR9UQI/
Calculation of radiating near-fields from aperture antennas, if obtained via brute-force 3D FE-based methods, is very computationally intensive. A better way is to limit the FE computation space to only a modest volume surrounding the antenna, and then use the computed fields therein to predict the radiated fields elsewhere. This short and informal note describes one way to do that, i.e., to compute Radiating Near-Fields within the Comsol RF module (in the frequency-domain formalism) using a near-field version of the Stratton-Chu Aperture Field Integration approximation method. This method effectively fills in the gap between Comsol's FE-based (but very-local) field computations and Comsol's included tool for computation of far-field patterns.<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/K4XT-hR9UQI" height="1" width="1" alt=""/>Wed, 17 Sep 2014 21:44:48 +00003.1410990288.247http://www.comsol.com/community/exchange/247/Initial stress
http://feedproxy.google.com/~r/ComsolExchange/~3/hBCWmhNL0A4/
alternative solution <br />
The equilibrium theory of in situ stresses<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/hBCWmhNL0A4" height="1" width="1" alt=""/>Tue, 05 Aug 2014 02:25:16 +00003.1407205516.243http://www.comsol.com/community/exchange/243/Magnetic Gear
http://feedproxy.google.com/~r/ComsolExchange/~3/DttLL-rUZts/
Additional materials for webinar -> http://www.comsol.com/events/2057/Modeliruem-v-COMSOL-Multiphysics<br />
<br />
Webinar created with support COMSOL Russian User Group -> http://vk.com/comsolmultiphysics<br /><img src="//feeds.feedburner.com/~r/ComsolExchange/~4/DttLL-rUZts" height="1" width="1" alt=""/>Fri, 13 Jun 2014 03:36:58 +00003.1402630618.241http://www.comsol.com/community/exchange/241/Deformation of free surface under pressure– 2D model with surface tension
http://feedproxy.google.com/~r/ComsolExchange/~3/gOQbN4vOoXA/
This model is concerned with the simulation of incompressible Newtonian fluid flow problems with surface tension. The fluid is initially at rest in a square tank. A Gaussian pressure is applied on the free surface which deformed the initially flat surface. This model is developed for a 2D transient analysis. The movement and deformation of the computational domain are accounted for by employing the Arbitrary Lagrangian-Eulerian (ALE) description of the fluid kinematics. The implementation of the model is detailled step by step in the pdf file for the version 3.5a.<br />
To visualize the results, you need to solve the comsol file.<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/gOQbN4vOoXA" height="1" width="1" alt=""/>Tue, 27 May 2014 06:09:29 +00003.1401170969.118http://www.comsol.com/community/exchange/118/Square drop oscillation under surface tension – 2D axi-symmetric model
http://feedproxy.google.com/~r/ComsolExchange/~3/XD4K52f1iRs/
This model is concerned with the simulation of incompressible Newtonian fluid flow problems with surface tension. An initially cubic drop of water is oscillating under surface tension forces. This model is developed for a 2D axi-symmetric transient analysis. The movement and deformation of the computational domain are accounted for by employing the Arbitrary Lagrangian-Eulerian (ALE) description of the fluid kinematics. <br />
The implementation of the model is detailled step by step in the pdf file fir the version 3.5a. To visualize the solution, you need to solve the model.<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/XD4K52f1iRs" height="1" width="1" alt=""/>Tue, 27 May 2014 05:35:30 +00003.1401168930.121http://www.comsol.com/community/exchange/121/2D modelling P-, S-, R-waves in geomassif (35a)
http://feedproxy.google.com/~r/ComsolExchange/~3/S5H8_Fn7kGI/
2G modelling P-, S-, R-waves in geomassif<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/S5H8_Fn7kGI" height="1" width="1" alt=""/>Thu, 07 Nov 2013 19:32:10 +00003.1383852730.239http://www.comsol.com/community/exchange/239/Elastic Relaxation of Pre-stressed Bilayer
http://feedproxy.google.com/~r/ComsolExchange/~3/wFneyJhwcU0/
In recent decade, the principle of bimetal bending was exploited in the field of thin films. Rolled-up micro- to nanotubes with multiple windings were obtained with this technology as well as wrinkled nanostructures. The competition of these two morphologies is studied by simulation of elastic relaxation with the help of Structural Mechanics Module. The structure consists of first layer compressed initially and second layer without initial strain. If the difference of the initial strains of the layers is sufficiently large, bending into the tube is preferred, otherwise wrinkling is observed. For medium strain gradient, intermixing shape of tube with wrinkles is the result of elastic relaxation. Additional information and qualitative experimental comparison can be found in article P. Cendula et al, submitted (2013).<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/wFneyJhwcU0" height="1" width="1" alt=""/>Tue, 15 Oct 2013 05:43:53 +00003.1381815833.232http://www.comsol.com/community/exchange/232/Generation of lofted NURBS curves for 3D Model generation with COMSOL
http://feedproxy.google.com/~r/ComsolExchange/~3/9C9H2PJL98s/
A key challenge to finding quantitative solutions to biological problems is to model the complex 3D geometry of naturally occurring structures. Model generation often starts from serial sections from CT or MRI scans, confocal microscopy, or physical sectioning. Third party CAD packages can be used to assemble stacks of serial sections to generate 3D models to import into COMSOL. In addition, prior to V4 of COMSOL, there was a “loft” command to allow construction of 3D models from serial sections within COMSOL. However, the loft feature is not currently available in COMSOL, presenting a hurdle for problems that depend on geometry construction within COMSOL (as opposed to a third party package). <br />
A solution for building 3D structures from serial sections has been developed based on the use of the COMSOL LiveLink for MATLAB module to construct lofted 3D NURBS (Non-uniform Rational B-Spline) geometries. The method, which could be generalized for other cases, was developed for generating the 3D geometry for a rat tibia as part of ongoing bone adaptation studies.<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/9C9H2PJL98s" height="1" width="1" alt=""/>Sat, 12 Oct 2013 15:54:35 +00003.1381593275.228http://www.comsol.com/community/exchange/228/student
http://feedproxy.google.com/~r/ComsolExchange/~3/f4dF-3MlbiE/
student<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/f4dF-3MlbiE" height="1" width="1" alt=""/>Thu, 10 Oct 2013 12:22:30 +00003.1381407750.226http://www.comsol.com/community/exchange/226/Finite Elements to Computational Engineering Sciences
http://feedproxy.google.com/~r/ComsolExchange/~3/E66QmCvmu0w/
This site develops discrete implementations of WS theory for diverse variety of problem statements <br />
in the computational engineering sciences. Unique to the FE discrete development, the resulting <br />
algorithms are immediately stated in computable form via a transparent object-oriented programming <br />
syntax. The engineering science problem classes developed herein include.<br />
<br />
1. heat conduction<br />
2. structural mechanics<br />
3. mechanical vibrations<br />
4. heat transfer, with convection and radiation<br />
5. fluid mechanics<br />
6. heat/mass convective transport<br />
<br />
For more information, please see: www.wiley.com/go/baker/finite<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/E66QmCvmu0w" height="1" width="1" alt=""/>Thu, 18 Apr 2013 07:34:16 +00003.1366270456.223http://www.comsol.com/community/exchange/223/UG Course Projects in Biomedical/Biological Transport Processes
http://feedproxy.google.com/~r/ComsolExchange/~3/tFe3ob2TT98/
A project-based course (taught since 1996) to help undergraduates think of computer simulation as an important practical tool in design and research projects in the industry as well as academia. Student groups come up with project ideas on their own and go through problem formulation all the way to parametric sensitivity analysis. COMSOL has drastically improved the computation capabilities and ease of use so that we can introduce more realistic physics, multiphysics or complex geometry and spend more time on model validation, written and oral communication, and design. All project reports are at https://courses.cit.cornell.edu/bee4530/pastprojects.html. <br />
<br />
A textbook integrates instruction of how to model transport processes (problem formulation, etc.) with COMSOL use (http://www.cambridge.org/us/knowledge/isbn/item2703298/?site_locale=en_US). The newcomer to modeling and/or COMSOL can use the Case Studies in this book to self-learn modeling in biological/biomedical applications.<br /><img src="//feeds.feedburner.com/~r/ComsolExchange/~4/tFe3ob2TT98" height="1" width="1" alt=""/>Thu, 28 Mar 2013 16:51:48 +00003.1364489508.216http://www.comsol.com/community/exchange/216/Mie scattering off plasmonic nanoparticles
http://feedproxy.google.com/~r/ComsolExchange/~3/xG5tQIF_QXk/
This is a general model to simulate light scattering off plasmonic or dielectric nano-particles or spherical nano-structures. I computed the total scattering cross-section (SCS), absorption cross-section (ACS), extinction cross-section (ECS), radar cross-section (RCS) and differential scattering cross-section (dSCS) of gold nanoparticles in the near UV, visible and near infrared range. Material properties are taken from peer-reviewed experimental data (P. B. Johnson and R. W. Christy, “Optical Constants of the Noble Metals,” Phys. Rev. B, vol. 6, no. 12, pp. 4370–4379, Dec. 1972). The model can be used as a starting point to compute the absorption and scattering properties of more complicated structures or metamolecules, with broken spherical symmetry and several constituents. This model completes the tutorial file "Optical Scattering off of a gold nano-sphere", by providing efficient ways to compute the total cross-sections. The obtained results match analytical predictions based on Mie theory.<br />
<br />
<br />
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NB : Models compatible with COMSOL 4.3 and 4.3a are available.To visualize the results, you may need to run the file.<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/xG5tQIF_QXk" height="1" width="1" alt=""/>Tue, 19 Mar 2013 16:22:58 +00003.1363710178.215http://www.comsol.com/community/exchange/215/Modeling of Binder Removal by Diffusion from Ceramic Green Body
http://feedproxy.google.com/~r/ComsolExchange/~3/SuJiAtHekYo/
<br />
<br />
Modeling of Binder Removal by Diffusion from Ceramic Green Bodies <br />
David G. Retzloff and Stephen J. Lombardo, University of Missouri<br />
<br />
This presentation delves into the fabrication of ceramic components via powder processing and the removal of the binder that aids in the processing of the ceramic green body. It begins with an introduction to the components involved in the process, and continues with the governing equations used for one-dimensional binder removal, decomposition reaction rate, as well as the relationships between weight fraction, volume fraction, specific volumes V1 and V2, and concentration as pertinent to the binder removal process. The presentation presents a step-by-step guide for how to model this in COMSOL. <br />
<br />
David G. Retzloff<br />
Department of Chemical Engineering, University of Missouri <br />
Presently an associate professor in the Chemical Engineering Department at the University of Missouri, David G. Retzloff received his PhD, MS, and BS from the University of Pittsburgh. He has previously worked as a consultant for AT&T and as a research engineer for Exxon. His focus is on analysis of dynamic systems. <br />
<br />
Stephen J. Lombardo<br />
Department of Mechanical & Aerospace Engineering, University of Missouri <br />
Currently a professor in the Mechanical and Aerospace Engineering Department at the University of Missouri, Stephen J. Lombardo received his PhD from the University of California-Berkeley, and a BS from Worcester Polytechnic Institute. His industrial experience includes Saint-Gobain Corporation and CeraMem Corporation. He focuses on Ceramic Materials and Ceramic Processing, Electronic Ceramics, and Transport Phenomena and Kinetics.<br /><img src="//feeds.feedburner.com/~r/ComsolExchange/~4/SuJiAtHekYo" height="1" width="1" alt=""/>Mon, 14 Jan 2013 14:52:45 +00003.1358175165.208http://www.comsol.com/community/exchange/208/UG Reserarch Projects with Professor Bruce A. Finlayson
http://feedproxy.google.com/~r/ComsolExchange/~3/jjrHR6pgR9c/
This web site <br />
http://www.chemecomp.com <br />
provides results of studies of microfluidic devices, to determine mixing properties, flow properties, and correlations and design information for laminar flow. The students were Dreyfus Undergraduate Research Scholars, under the Senior Mentor Program awarded to Professor Finlayson by the Camille & Henry Dreyfus Foundation, Inc.<br />
<br />
The web site also has links to information about Comsol that goes beyond the book, Introduction to Chemical Engineering Computing, 2nd ed., Wiley (2012).<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/jjrHR6pgR9c" height="1" width="1" alt=""/>Mon, 14 Jan 2013 12:15:06 +00003.1358165706.210http://www.comsol.com/community/exchange/210/Electromagnetic and hydrodynamic transient coupling
http://feedproxy.google.com/~r/ComsolExchange/~3/A_4jawdWErQ/
In this model transient electromagnetics and hydrodynamics are coupled<br />
in a so-called strong MHD coupling in a 2D axisymmetric geometry, with<br />
k-epsilon RANS turbulence equations for the fluid flow.<br />
<br />
This model focuses on the strong coupling process involved and no<br />
specific checking regarding solver or mesh convergence analysis has been<br />
performed here. Moreover, there is no special treatment of the Hartmann<br />
boundary layer (interaction between the fluid boundary layer and the<br />
transverse magnetic field). Default wall functions available with<br />
k-epsilon model have been used, together with a continuity in the<br />
magnetic vector potential Aphi at the wall. Aphi is in this model not<br />
modified by the turbulent boundary layer.<br />
To be successful, one should take into account that good initial<br />
conditions for the fluid flow must be provided to the time-dependent<br />
solver. This process makes use of 5 stationary steps.<br />
It is possible to use fewer stationary steps, however it may cause more<br />
convergence errors (Tfails and NLfails) or even not converge at all.<br />
<br />
Also, one should adjust the time-dependent solver by segregating the<br />
magnetic vector potential Aphi in a separated segregated step. Sometimes<br />
it might be useful also to exclude algebraic degrees of freedom from the<br />
evauation of error in the time-dependent algorithm. This is done in the<br />
advanced options of the solver.<br />
<br />
One should note that the conductivity of mercury if significantly<br />
increased in order to better illustrate the physical phenomena that<br />
appears at this moderate magnetic Reynolds number. Highly conducting<br />
flow "takes" magnetic field in the direction of the flow and therefore<br />
it is not symetric as it would be in case of zero velocity (magnetic<br />
Reynods number 0). The full time-dependent solution reveals the<br />
behaviour in time of this kind of strong coupling, which is not<br />
frequently described in the literature.<br />
<br />
Many thanks to Eric Favre, from COMSOL France, for his technical support<br />
associated with this case.<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/A_4jawdWErQ" height="1" width="1" alt=""/>Mon, 17 Dec 2012 08:01:18 +00003.1355731278.207http://www.comsol.com/community/exchange/207/Domain decomposition for hyperbolic equations
http://feedproxy.google.com/~r/ComsolExchange/~3/KH2JIR59bKY/
Domain decomposition for hyperbolic equations<br />
Mikhael Balabane , Université Paris 13<br />
Stephan Savarese, COMSOL France<br />
<br />
This model shows how to solve an iterative algorithm using domain decomposition techniques.<br />
<br />
Coefficient Form PDE u1 (c4) solves for u1<br />
Coefficient Form PDE u2 (c) solves for u2<br />
Coefficient Form PDE v1 (c2) stores u1 into v1<br />
Coefficient Form PDE v2 (c3) stores u2 into v2<br />
Then compute and iterate as follows:<br />
<br />
1. Compute Init U<br />
2. In LOOP > Step1 > Values of Variables not solved for : select Solution : Init U , then Compute<br />
3. In LOOP > Step1 > Values of Variables not solved for : select Solution : LOOP, then Compute as many times as necessary to converge<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/KH2JIR59bKY" height="1" width="1" alt=""/>Mon, 08 Oct 2012 08:23:14 +00003.1349684594.205http://www.comsol.com/community/exchange/205/2D-Cyclic Voltammetry Model: 1 electron 2 speicies dillute diffusion
http://feedproxy.google.com/~r/ComsolExchange/~3/s4yF7dUsQo8/
A simple COMSOL mph cyclic voltammetry (CV) 2D time-dependent model was developed. The model presumes the electrode kinetics are described by a 1 electron transfer process. The transport of a reduced and an oxidized species is described by time-dependent mass transfer principles for diffusion under dilute conditions.<br />
<br />
The model is that of a two electrode cell. The reaction at the working electrode is described by concentration dependent Butler-Volmer kinetics. The counter electroded is modeled so that it behaves like an ideal reference electrode. <br />
<br />
As in an experimental CV study, the applied cell voltage sets the potential of the working electrode with respect to the reference electrode, in our case also the counter electrode. In the model, the potential of the counter electrode is set to that of the electrolyte at the electrode surface and that potential with respect to ground is set to zero. There is very little potential drop between electrodes in the electrolyte. There is no current flow in the counter electrode. Thus all of the cell's response to an applied potential is the result of changes between the working electrode and the electrolyte next to its active surface, exactly the outcome one looks for in selecting a reference electrode for CV studies.<br />
<br />
The model is seen as a tool to help one interpret experimental voltammograms. In this regard, it must also be seen as template for building models with more complex electrochemistry conditions, e.g., multiple electron transfer processes, with chemical reactions and more complex mass transfer conditions. One can then form an hypothesis regarding the interpretation of an experimentally obtained CV, The COMSOL simulations will either bolster ones support for the interpretation or be proof that one needs a better hypothesis.<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/s4yF7dUsQo8" height="1" width="1" alt=""/>Mon, 25 Jun 2012 13:30:26 +00003.1340631026.203http://www.comsol.com/community/exchange/203/Another Pandulum (3d truss element)
http://feedproxy.google.com/~r/ComsolExchange/~3/GmOTjDmqzb4/
Pandulum model using 3d truss element.<br />
initial position is from (0,0,0) to (0,2,10).<br />
(0,2,10) end is pinned.<br />
(0,0,0) end has 10kg mass.<br />
gravity is applied in -z direction.<br />
<br />
analitical solution is approximated very well:<br />
period =sqrt(Length/gravity)<br />
<br />
the model image shows the y displacement vs time.<img src="//feeds.feedburner.com/~r/ComsolExchange/~4/GmOTjDmqzb4" height="1" width="1" alt=""/>Wed, 18 Apr 2012 09:00:11 +00003.1334739611.200http://www.comsol.com/community/exchange/200/