COMSOL Exchange
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Receive updates on user-generated models in COMSOL ExchangeTue, 21 Feb 2017 11:45:07 +0000COMSOL Exchangehttp://www.comsol.com/shared/images/logos/comsol_logo.gif
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Simulations of Fish Swimming
http://feedproxy.google.com/~r/ComsolExchange/~3/dR9UV-TH87o/
We submit two different COMSOL5.2a models which simulate the swimming of a fish, specifically, the carangiform swimming in a virtual aquarium. The flexural motion of the fish is obtained by using a time-dependent field of distortions, meant to represent the action of fish muscles. Both models make use of both the moving mesh technique and the remeshing feature, and require about 10 Gb of RAM, and more than a day to run. The models are not yet solved (to avoid huge file upload), but are ready to run.<br />
<br />
The principal differences between the two models are in the geometry and the activation law for the fish muscles. The model Fish_COMSOL_a.mph is more indicated for robotics applications and runs about for 30 hours, while simulation of Fish_COMSOL_b.mph is more indicated for biology studies and runs for about 50 hours. <br />
<br />
It is possible to change the final time of simulation so to have shorter run times, or choose coarser mesh (Remark: fish swimming direction may change with a coarser mesh). <br />
<br />
Soon we will upload a PDF file to describe better the settings and the features of the models. Stay tuned!<br />
<br />
Further details in: <br />
<br />
M. Curatolo, L. Teresi.<br />
Modeling and Simulation of Fish Swimming with Active Muscles. Journal of Theoretical Biology, (2016). <br />
Doi: 10.1016/j.jtbi.2016.08.025<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/dR9UV-TH87o" height="1" width="1" alt=""/>Tue, 21 Feb 2017 11:45:07 +00003.1487677507.501http://www.comsol.com/community/exchange/501/What is wrong in this superscatterer sctructure?
http://feedproxy.google.com/~r/ComsolExchange/~3/pZkbpFersyY/
I read a paper about superscatterer blocking structure. [1]<br />
<br />
[1] Xudong Luo, Tao Yang, Yongwei Gu, Huanyang Chen, Hongru Ma, 'Conceal an entrance by means of superscatterer,' Applied Physics Letters 94, 223513 (2009).<br />
<br />
Unlike what is shown in the paper, EM waves leak in my simulations as shown in the attached image. Would anyone help me or correct me with this simulation of superscatterer concealing structure?<br />
<br />
I also attached cylindrical superscattering structure for sharing or exchanging.<br />
<br />
Thanks in advance.<br />
<br /><img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/pZkbpFersyY" height="1" width="1" alt=""/>Tue, 24 Jan 2017 11:52:22 +00003.1485258742.493http://www.comsol.com/community/exchange/493/Modelling Magma Intrusion in Sills
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We used COMSOL Multi physics (Pipe and Particle Tracing Modules) to simulate the lateral, pressure driven flow of viscous magma in 2 and 3D. The model uses field (digital) images of the magmatic intrusion as the basis for the FE mesh. All calculations are solved in that geometry. As well as recovering average flow rates for a range of viscosities typical of natural magmas we were able to identify the presence of (non-thermal) eddies at undulations in the upper and lower contact surfaces. Eddies scale with the fluid flow properties and dampen out as viscosity increases (Re < 1000). Particle tracing allowed us to map out the orbital dynamics of particles (assumed to be crystals in magma) 'tuned' the density range common in naturally occurring minerals. These provisional results suggest that in 3D the eddy structures are roll-like and extend normal to the mean flow direction. Their presence, along with the potential for mixing of particles (crystals) trapped for a period of time from the main flow is a hitherto undocumented process in magma fluid dynamics.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/Uik-Mp8YQqk" height="1" width="1" alt=""/>Thu, 22 Dec 2016 09:43:14 +00003.1482399794.491http://www.comsol.com/community/exchange/491/A Modified Laplacian Mesh Editing by Weighting
http://feedproxy.google.com/~r/ComsolExchange/~3/j5rx4ft5OEM/
First, we use the solution of Laplace equation on surface as a weight, with boundary condition 0 for fixed parts and 1 for moving parts. By some mathematical techniques to the weight, we can editing the surface (stl mesh) with rotation or displacement. This model is a small test of rotating a branch on a given tree, and simulation results are given in version 5.1. Have fun!<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/j5rx4ft5OEM" height="1" width="1" alt=""/>Tue, 25 Oct 2016 05:53:19 +00003.1477374799.473http://www.comsol.com/community/exchange/473/Surface plasmon polariton excitation in Kretschmann configuration
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Excitation of surface plasmon polaritions at the gold-air interface in Kretschmann configuration.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/u-zU_cbjfZE" height="1" width="1" alt=""/>Sun, 23 Oct 2016 09:03:40 +00003.1477213420.471http://www.comsol.com/community/exchange/471/Test of topology optimization for Poisson's Equation
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"Topology optimization is a mathematical approach that optimizes material layout within a given design space, for a given set of loads and boundary conditions such that the resulting layout meets a prescribed set of performance targets. Using topology optimization, engineers can find the best concept design that meets the design requirements."-- From Wikipedia. <br />
This model is a small test of designing the best structure for heat dissipation problem. <br />
The version is 5.2<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/bkhzuxokSJU" height="1" width="1" alt=""/>Sun, 18 Sep 2016 05:55:27 +00003.1474178127.463http://www.comsol.com/community/exchange/463/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<br />
<br />
Updated on Aug 9, 2016.<br />
I've implemented many comments kindly supplied by our careful users.<br />
I intentionally retain the original version (5.0) though 5.2a is now<br />
in use. Perhaps in our next models new features will be implemented.<br />
Thank you very much for your feedback! <br />
<br />
Model_No_4 is updated on Aug 18, 2016.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/lv3ghww-nVA" height="1" width="1" alt=""/>Thu, 18 Aug 2016 14:16:41 +00003.1471529801.361http://www.comsol.com/community/exchange/361/Shape of a static meniscus pinned at the contact line from Young-Laplace equation
http://feedproxy.google.com/~r/ComsolExchange/~3/rz5WYzdpTLQ/
This is a simple example for equation based modeling where the static Young-Laplace equation - [Delta P] = [surface tension] * [divergence of the surface normal vector] - is solved to determine the shape of a liquid meniscus pinned at an arbitrarily shaped contact line. In this example, the contact line looks like a keyhole, and problem is solved for a range of surface tensions and pressure differences.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/rz5WYzdpTLQ" height="1" width="1" alt=""/>Wed, 03 Aug 2016 21:12:00 +00003.1470258720.462http://www.comsol.com/community/exchange/462/Maxwell-Wagner Model of Blood Permittivity
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Maxwell-Wagner model is used for explanation of frequency dispersion, which takes place for permittivity at various kinds of suspensions. In particular, this phenomenon is observed in the blood. The paper shows how dielectric properties of suspensions may be modeled with COMSOL. The extension of Maxwell-Wagner model for cubic symmetry of suspended particles is considered.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/SbPbH0GV4Qo" height="1" width="1" alt=""/>Wed, 27 Jul 2016 11:06:42 +00003.1469617602.461http://www.comsol.com/community/exchange/461/How to simulate microwave heating of food rotation
http://feedproxy.google.com/~r/ComsolExchange/~3/AUhc651Ox9E/
How to simulate microwave heating of food rotation,This bit difficult but very interesting.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/AUhc651Ox9E" height="1" width="1" alt=""/>Tue, 19 Jul 2016 14:13:29 +00003.1468937609.453http://www.comsol.com/community/exchange/453/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 />
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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
http://feedproxy.google.com/~r/ComsolExchange/~3/Otu-vu29x-w/
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
http://feedproxy.google.com/~r/ComsolExchange/~3/NvytVGYXrfc/
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
http://feedproxy.google.com/~r/ComsolExchange/~3/_ZCOKbodvHU/
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
http://feedproxy.google.com/~r/ComsolExchange/~3/SrY201Eo9Y8/
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/Material: Water H2O
http://feedproxy.google.com/~r/ComsolExchange/~3/DXbJKkq793o/
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/