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Receive updates on user-generated models in COMSOL ExchangeMon, 25 Jan 2016 15:41:49 +0000COMSOL Exchangehttp://www.comsol.com/shared/images/logos/comsol_logo.gif
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Phononic Band-Gap Structure Eigenfrequency Analysis
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Phononic crystals are artificially manufactured structures, or materials, with periodic constitutive or geometric properties designed to influence the characteristics of mechanical wave propagation. They can be engineered to isolate vibration in a certain frequency range. Vibration in that frequency range, called a band gap, is attenuated by a mechanism of wave interferences within the periodic system. <br />
<br />
To illustrate, we created this model involving a 2D periodic structure with a unit cell composed of a stiff inner core and a softer outer matrix material, designed to have a band gap around 60-70 kHz. We applied Bloch boundary conditions to constrain the displacements of the unit cell, and set up a complex Eigenfrequency Study with a Parametric Sweep spanning the wave vectors that represent the boundaries of the irreducible Brillouin zone. When we plot the wave propagation frequencies for all wave numbers, a band gap appears as a region where no wave propagation branches exist.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/9dv1aIw6l24" height="1" width="1" alt=""/>Mon, 25 Jan 2016 15:41:49 +00003.1453736509.432http://www.comsol.com/community/exchange/432/Coupled hydro-thermal model
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Modeling the coupled hydro-thermal process in enhanced geothermal<br />
systems<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/Otu-vu29x-w" height="1" width="1" alt=""/>Wed, 13 Jan 2016 08:08:28 +00003.1452672508.423http://www.comsol.com/community/exchange/423/Laserwelding
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Laser Welding of PMMA with 1 W Laser.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/foZRba2Qe7Y" height="1" width="1" alt=""/>Mon, 07 Sep 2015 13:09:23 +00003.1441631363.401http://www.comsol.com/community/exchange/401/Allen-Cahn (nonlinear reaction diffusion) Equation
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The Allen–Cahn equation ( John W. Cahn and Sam Allen) is a nonlinear reaction-diffusion equation of mathematical physics which describes the process of phase separation in iron alloys including order-disorder transitions.<br />
The partial differential equation<br />
$\frac{\partial u}{\partial t} = \epsilon \Delta u + F(u)$<br />
where $F(u)$is the free energy density and<br />
$F(u) = u(1-u)(u-\frac{1}{2}+0.1)$.<br />
By using the Heat Equation in Mathmatica Branch, we add the free energy density as a source term.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/HkxHCsAPffo" height="1" width="1" alt=""/>Tue, 01 Sep 2015 08:36:09 +00003.1441096569.331http://www.comsol.com/community/exchange/331/A test about discontinuous Galerkin (dG) method for Poisson Equation
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Most FEM are absed on the continuous Galerkin (cG) method, a finite element method formulated relative to a weak formulation of a particular model system. Unlike traditional FEM (cG) methods that the numerical solution are conforming, the DG method works over a trial space of functions that are only piecewise continuous, and thus often comprise more inclusive function spaces than the finite-dimensional inner product subspaces utilized in conforming methods.<br />
<br />
We focus on a typical elliptic problems which is also called Piosson Equation:<br />
\[<br />
-\Delta u=f \mathrm{in} \Omega<br />
u=0 \mathrm{on} \partial \Omega<br />
\]<br />
We let $\Omega=[0,1]^2$, $f=2pi^2\sin(2\pi x)\sin(2\pi y)$, <br />
and use the jump penalization type dG method.<br />
<br />
Key function: up(), down() WeakForm PDE<br />
Solving by COMSOL 4.4<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/NvytVGYXrfc" height="1" width="1" alt=""/>Tue, 01 Sep 2015 08:35:08 +00003.1441096508.373http://www.comsol.com/community/exchange/373/ Convection dominated Convection-Diffusion Equation by upwind discontinuous Galerkin (dG) method
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We consider the Convection-Diffusion Equation with very small diffusion coefficient $\mu$:<br />
\[<br />
-mu\Delta u + \mathbf{\beta}\dot\nabla u =f \mathrm{in}~ \Omega<br />
u=g(x,y) \mathrm{on}~ partial\Omega<br />
\]<br />
First we use the Convection-Diffusion Equation function of The Classical PDE Interfaces in COMSOL 4.4. <br />
Then, we use the WeakForm PDE function and choose shape function type to be discontinuous Largrange. <br />
We compare these two solutions. <br />
<br />
Key functions : up() down() nx ny WeakForm PDE<br />
Solving by COMSOL 4.4 <br /><img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/_ZCOKbodvHU" height="1" width="1" alt=""/>Tue, 01 Sep 2015 08:34:33 +00003.1441096473.383http://www.comsol.com/community/exchange/383/Microsphere resonator
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This model reproduces the simulation results from:<br />
http://dx.doi.org/10.1063/1.4801474<br />
Solutions were stripped so you will have to run the simulation to see the results. That may take a while (6min, with my 64Gb RAM PC). So if you have less resources, try first reducing the mesh.<br />
<br />
The model was done using the Wave Optics module with Comsol 4.4.0.248<br />
<br />
Note: the reference above is also available from here:<br />
http://arrow.dit.ie/cgi/viewcontent.cgi?article=1129&context=engscheceart<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/7zgTFRZDF7k" height="1" width="1" alt=""/>Wed, 19 Aug 2015 11:55:38 +00003.1439985338.372http://www.comsol.com/community/exchange/372/3D fiber coupler
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Optical fiber coupler, based on the tutorial "Directional Coupler" using the Wave Optics module with Comsol version 4.4.0.248.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/SrY201Eo9Y8" height="1" width="1" alt=""/>Wed, 12 Aug 2015 09:50:12 +00003.1439373012.251http://www.comsol.com/community/exchange/251/2D Directional Coupler
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A simplification of the 3D directional coupler using the RF Module and Boundary Mode Analysis. Just download and compute to see the results. Made with Comsol version 4.4.0.248. Enjoy!<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/XMa6bf-HqEY" height="1" width="1" alt=""/>Fri, 03 Jul 2015 18:23:17 +00003.1435947797.362http://www.comsol.com/community/exchange/362/Tutorial models for COMSOL Webinar "Simulating Graphene-Based Photonic and Optoelectronic Devices"
http://feedproxy.google.com/~r/ComsolExchange/~3/lv3ghww-nVA/
Basic tutorial models for COMSOL Webinar<br />
"Simulating Graphene-Based Photonic and Optoelectronic Devices" <br />
by Prof. Alexander Kildishev, Purdue University, USA<br />
Validation with a meshless method performed by <br />
Dr. Lucie Prokopeva, Novosibirsk University, Russia<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/lv3ghww-nVA" height="1" width="1" alt=""/>Wed, 10 Jun 2015 21:38:38 +00003.1433972318.361http://www.comsol.com/community/exchange/361/It is very interesting.
http://feedproxy.google.com/~r/ComsolExchange/~3/j3ar_hutrhE/
It is very interesting.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/j3ar_hutrhE" height="1" width="1" alt=""/>Sun, 31 May 2015 13:08:49 +00003.1433077729.351http://www.comsol.com/community/exchange/351/Material: Water H2O
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Just open and save material to your own User-Defined Library, or copy the Interpolations to your own material. <br />
<br />
Hale and Querry 1973- Water; n,k 0.2-200 µm; 25 °C<br />
<br />
Data from: http://refractiveindex.info/?shelf=main&book=H2O&page=Hale<br />
<br />
Original data from:G. M. Hale and M. R. Querry. Optical Constants of Water in the 200-nm to 200-µm Wavelength Region, Appl. Opt. 12, 555-563 (1973)<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/DXbJKkq793o" height="1" width="1" alt=""/>Wed, 20 May 2015 05:08:21 +00003.1432098501.281http://www.comsol.com/community/exchange/281/Material: Fused Silica with sellmeier refractive index
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Material Fused Silica, just open and save material to your own User-Defined Library, or copy the equation to your own material.<br />
<br />
<br />
Refractive index data (0.21-3.71 µm) based on Sellmeier equation from: H. Malitson. Interspecimen Comparison of the Refractive Index of Fused Silica, J. Opt. Soc. Am. 55, 1205-1208 (1965).<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/fQ-Dx0suwPE" height="1" width="1" alt=""/>Wed, 20 May 2015 05:08:04 +00003.1432098484.271http://www.comsol.com/community/exchange/271/Material: Cr with Refractive index
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Data from: <br />
http://refractiveindex.info/?shelf=main&book=Cr&page=Rakic<br />
Original data:<br />
A. D. Rakić, A. B. Djurišic, J. M. Elazar, and M. L. Majewski. Optical properties of metallic films for vertical-cavity optoelectronic devices, Appl. Opt. 37, 5271-5283 (1998)<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/SCsYxNkQpbo" height="1" width="1" alt=""/>Wed, 20 May 2015 05:07:37 +00003.1432098457.341http://www.comsol.com/community/exchange/341/2D modelling P-, S-, R-waves in geomassif (35a)
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2G modelling P-, S-, R-waves in geomassif<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/S5H8_Fn7kGI" height="1" width="1" alt=""/>Wed, 15 Apr 2015 01:50:39 +00003.1429062639.239http://www.comsol.com/community/exchange/239/Magnets attract each other
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Magnets attract each other，it is very interesting!<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/gYAYvswLNrQ" height="1" width="1" alt=""/>Sun, 12 Apr 2015 11:37:20 +00003.1428838640.321http://www.comsol.com/community/exchange/321/2D wave equation
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This is a simple model for beginners. <br />
2D waves equations is solved on a rectangular region. An exponential (2D) perturbation is generated in the centre of the study region and its evolvement with time is studied.<br />
For simplicity no units are considered. <br />
Following boundary conditions are imposed on the edges of rectangle:<br />
1. Zero flux at boundaries.<br />
2. Dirichlet boundary condition.<br />
<br /><img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/Hz-fCMqdess" height="1" width="1" alt=""/>Tue, 24 Mar 2015 15:04:17 +00003.1427209457.311http://www.comsol.com/community/exchange/311/The cup is leaking model
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The cup is leaking model,It is very interesting.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/AdrtyFPqAQY" height="1" width="1" alt=""/>Fri, 06 Mar 2015 14:41:54 +00003.1425652914.301http://www.comsol.com/community/exchange/301/Two axis Gimbal
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A two axis pendulum using a gimbal mechanism, rigid domains.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/MbBVT-Vn8Z0" height="1" width="1" alt=""/>Thu, 19 Feb 2015 15:49:21 +00003.1424360961.291http://www.comsol.com/community/exchange/291/Influence of vessels on electroporation-based treatments of tumors
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Electroporation-based treatments rely on increasing the permeability of the cell membrane by high voltage electric pulses applied to tissue via electrodes. To ensure that the whole tumor is covered with sufficiently high electric field, accurate numerical models are built based on individual patient anatomy and taking into account electrical properties of different tissues.<br />
We have designed a series of simplified models in order to establish the effect of presence of blood vessels in tumor vicinity on the electric field distribution and subsequently the coverage of the tumor with a sufficiently high electric field. Each of these models includes a simple sphere and cylinders geometry that represent a tumor, vessel, and needle electrodes. Different scenarios can be observed by varying tumor size, vessel size, distance between vessel and tumor, electrode configurations (with or without a central electrode) and the position of the vessel relative to electrodes: perpendicular or parallel.<br />
The model files included here are the two basic models from which all other variations can be generated. First model, "ECT4H10" is a model of an electrochemotherapy treatment of a 10 mm diameter tumor with 4 electrodes around the tumor and a vessel perpendicular to the electrodes. Second model, "ECT5V30" is a model of an electrochemotherapy treatment of a 30 mm diameter tumor with 4 electrodes around the tumor and 1 central electrode and a vessel parallel with the electrodes.<br />
NOTE: In order to keep the model files small the models include only one instance of study. The full model requires adding more studies of the same kind so that each study is solved for exactly one physics while others are set to inactive.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/Nq-JE5MtcCE" height="1" width="1" alt=""/>Thu, 22 Jan 2015 13:34:04 +00003.1421933644.261http://www.comsol.com/community/exchange/261/