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Receive updates on user-generated models in COMSOL ExchangeWed, 06 Sep 2017 07:12:46 +0000COMSOL Exchangehttp://www.comsol.com/shared/images/logos/comsol_logo.gif
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Simulations of Fish Swimming
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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 />
UPDATE: We uploaded the files using the new version of COMSOL. We also submit a new file: Fish_COMSOL53_a_light.mph with a coarser mesh to run faster simulations (computation time ~ 4 hours) but do not trust in the final result.<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<br />
<br />
https://www.comsol.com/blogs/studying-the-swimming-patterns-of-fish-with-simulation/<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/dR9UV-TH87o" height="1" width="1" alt=""/>Wed, 06 Sep 2017 07:12:46 +00003.1504681966.501http://www.comsol.com/community/exchange/501/Surface plasmon polaritons by Kretschmann-Raether
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Excitation of surface plasmon polaritions at the silver-air interface in Kretschmann-Raether configuration - Tutorial model for COMSOL/LFW webinar "Modeling Optoelectronic Devices and Plasmon Effects".<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/cNTdKPEynYM" height="1" width="1" alt=""/>Wed, 23 Aug 2017 15:40:19 +00003.1503502819.562http://www.comsol.com/community/exchange/562/Surface plasmon polaritons by scattering
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Excitation of surface plasmon polaritons at the silver-air interface by scattering configuration - Tutorial model for COMSOL/LFW webinar "Modeling Optoelectronic Devices and Plasmon Effects"<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/h69oW5SX-bk" height="1" width="1" alt=""/>Wed, 23 Aug 2017 15:39:48 +00003.1503502788.572http://www.comsol.com/community/exchange/572/Simulation of a four-electrode impedance spectroscopy system and a biological cell in culture medium
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This is a simulator of a four-electrode impedance spectroscopy (IS) system, and consists of models of four microelectrodes, medium, and a biological cell, in an electrically insulated cell culture well. The model was used to demonstrate the usage of simulations and lead field theory in the design of microelectrode array systems for cell biology applications to detect and assess biological cells using IS. For more information, please, see [1].<br />
<br />
Please, cite [1] when reporting any work done with the simulator or with any derived simulator.<br />
<br />
[1] Marcel Böttrich, Jarno M. A. Tanskanen, and Jari A. K. Hyttinen, ”Lead field theory provides a powerful tool for designing microelectrode array impedance measurements for biological cell detection and observation,” BioMedical Engineering OnLine, in press.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/S74ZQ3MM4-M" height="1" width="1" alt=""/>Tue, 20 Jun 2017 20:38:05 +00003.1497991085.551http://www.comsol.com/community/exchange/551/RVE with periodic boundary conditions
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Representative Volume Element (RVE) with periodic boundary conditions<br />
- 2D plane strain model.<br />
- Prescribe average deformation.<br />
- Calculate effective/average stress.<br />
- Perturbation method to calculate effective stiffness tensor.<br /><img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/2oHw9OfY2Dw" height="1" width="1" alt=""/>Thu, 25 May 2017 12:24:43 +00003.1495715083.542http://www.comsol.com/community/exchange/542/Surface Mounted Permanent Magnet Synchronous Machine
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This model recreates the SM-PMSM published in [1]. The machine is random-wound; therefore slot conductors are represented in a homogenized way. An analytical model and test data for this machine are presented in [1]. The results are shown to match those obtained from the analytical model when saturation is ignored, and from test data when saturation is considered. The machine losses are presently ignored.<br />
<br />
The Torque study obtains a torque waveform over rotation of one slot for a given current command, as calculated from flux linkages. The average torque produced may subsequently be obtained. It is noted that, being an overall machine energy-based evaluation (within FEA), this study is not expected to result in an accurate representation of torque ripple over the slot (which would require a significantly higher number of air-gap mesh elements, as well as convergence on the torque obtained from Maxwell Stress Tensor). It is, however, expected to provide an accurate value for average torque and flux linkages in the q- and d-axes. <br />
<br />
Setting the current command to approximately zero and the Iron behavior to linear steel using "relative permeability", the average d-axis flux linkage due to the magnet is found to be in reasonable agreement with the analytical model results shown in Section IX of [1]. Setting the Iron behavior to nonlinear steel using "HB curve" results in an average d-axis flux linkage value in agreement with experimental data shown in Table II of [1]. <br />
<br />
The FluxLinkageMap study sweeps the current magnitude and angle, as well as rotor position over one slot. A flux linkage map is then obtained as a function of current magnitude and angle by averaging the values over one slot of rotor positions.<br />
<br />
[1] B. N. Cassimere, S. D. Sudhoff, D. H. Sudhoff, "Analytical Design Model for Surface-Mounted Permanent-Magnet Synchronous Machines", IEEE Transactions on Energy Conversion, v. 24, no. 2, June 2009.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/bdX-_z0dkec" height="1" width="1" alt=""/>Wed, 24 May 2017 18:25:10 +00003.1495650310.532http://www.comsol.com/community/exchange/532/Conventional_Classic_DLVO
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The total interaction energy of colloids according to the Conventional Classic DLVO, Non-retarded Attractive van der Waals interaction and Repulsive electrostatic interaction energy, for a Sphere-Plate configuration of constant surface potential. Conventional because is subject to the limitations of the Derjaguin approximation, the equations were obtained from such approximation, and because the equations are broadly used in colloid science.<br />
REFS:<br />
*Elimelech, Menachem, John Gregory, and Xiadong Jia. Particle deposition and aggregation: measurement, modelling and simulation. Butterworth-Heinemann, 2013.<br />
*Hogg, R. T. W. D. W., To Wo Healy, and D. W. Fuerstenau. "Mutual coagulation of colloidal dispersions." Transactions of the Faraday Society 62 (1966): 1638-1651.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/r8fdA7BpPZA" height="1" width="1" alt=""/>Wed, 17 May 2017 09:18:25 +00003.1495012705.513http://www.comsol.com/community/exchange/513/Gas electron multiplier
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Gas electron multipliers (GEM) are extensively used in nuclear and particle physics experiments as part of the detection system. The present model showed the basic working principle of a GEM, which is based on the electron drift or diffusion in the gas medium, followed by the subsequent electron multiplication inside the GEM holes.<img src="http://feeds.feedburner.com/~r/ComsolExchange/~4/vmzj1z1DjhA" height="1" width="1" alt=""/>Sun, 05 Mar 2017 13:42:21 +00003.1488721341.511http://www.comsol.com/community/exchange/511/What is wrong in this superscatterer sctructure?
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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/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/Tutorial models for COMSOL Webinar "Simulating Graphene-Based Photonic and Optoelectronic Devices"
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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
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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
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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 />
<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/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/