Latest Discussions - COMSOL Forums https://www.comsol.com/forum/ Most recent forum discussions Wed, 17 Jan 2018 04:12:35 +0000 COMSOL Forum: Latest Discussions https://www.comsol.com/shared/images/logos/comsol_logo.gif https://www.comsol.com/forum/ Three phase transformer https://www.comsol.com/forum/thread/163921/three-phase-transformer?last=2018-01-17T04:12:35Z <p>How to design a Three phase transformer using COMOSL Multiphysics</p> Wed, 17 Jan 2018 04:12:35 +0000 4.2018-01-17 04:12:35.163921 Permanent Electrical Polarization in Material https://www.comsol.com/forum/thread/163912/permanent-electrical-polarization-in-material?last=2018-01-17T02:03:49Z <p>I'd like to give a material a permanent electrical Polarization, but I can't find out if this possible in COMSOL. For the magnetic case, there exists a material property "Permanent Magnet Magnetic Flux Density Norm" under the AC/DC materials. This creates a material with a permanent M field inside (or that's my understanding). Does anyone know a way to do this for a permanent P field inside a material directly (like an <a href="https://en.wikipedia.org/wiki/Electret">electret</a>).</p> <p>The closest thing I can think to do is assign surface boundary charge densities and make the dielectric of the material inbetween the surface charge densities very large. This would look similar to a permanent polarization.</p> Wed, 17 Jan 2018 02:03:49 +0000 4.2018-01-17 02:03:49.163912 Modeling transmission loss for triple pane window https://www.comsol.com/forum/thread/163902/modeling-transmission-loss-for-triple-pane-window?last=2018-01-16T23:03:17Z <p>HI, I am trying to model a triple pane windoe to compute the transmission loss . I was wondering if there is any tutorials and examples that can be helpfull. Thanks peyman</p> Tue, 16 Jan 2018 23:03:17 +0000 4.2018-01-16 23:03:17.163902 Can CFD Module be used to simulate fluid going through translational motion? https://www.comsol.com/forum/thread/163882/can-cfd-module-be-used-to-simulate-fluid-going-through-translational-motion?last=2018-01-16T19:54:53Z <p>Hi Per title. I know that Rotational Machinery can simulate rotation. But I want translational motion. I want a well to translate in a circular motion. Is it possible to accomplish this with COMSOL? Thanks.</p> Tue, 16 Jan 2018 19:54:53 +0000 4.2018-01-16 19:54:53.163882 How to modify the input excitation in mode field analysis https://www.comsol.com/forum/thread/163881/how-to-modify-the-input-excitation-in-mode-field-analysis?last=2018-01-16T17:30:08Z <p>Dear collegues,</p> <p>I have already simulated several PCF mode field distributions but I would like to know how can I modify the input excitation.</p> <p>I mean, how to modify the mode field diameter of a gausian beam input to simultate SMF or MMF just before my PCF (splice SMF-MMF)</p> <p>Thanks in advance</p> Tue, 16 Jan 2018 17:30:08 +0000 4.2018-01-16 17:30:08.163881 Unexpected envelop around a sine wave https://www.comsol.com/forum/thread/163831/unexpected-envelop-around-a-sine-wave?last=2018-01-16T21:31:11Z <p>Hello Everyone,</p> <p>I am trying to build a sine wave through analytical functions, but when I am increasing the frequency, I see an unexpected envelop around the signal.</p> <p>If I use following formulae, then I get the signal as shown in attachment 1: sin(2x3.14x1000[Hz]xt)</p> <p>And if I use following, what I get is shown in attachment 2: sin(2xpix1000[Hz]xt)</p> <p>Can anyone explain me why I am getting such behaviour.</p> <p>Thank you</p> Tue, 16 Jan 2018 15:34:21 +0000 4.2018-01-16 15:34:21.163831 How is "Losses" in coil parameter (mef) defined? https://www.comsol.com/forum/thread/163811/how-is-losses-in-coil-parameter-mef-defined?last=2018-01-16T11:37:24Z <p>Hallo, I have built a model of transforemr winding and am trying to calculate the losses in this model besides the capacitance and inductance at different frequeices。</p> <p>I have chosen "magnetic and electric fields " (mef) as the physics and "single-turn coil" for the winding conductors.</p> <p>I want to know how is Losses defined? Is it the option "Power" in coil parameter (mef) global evaluation? I already know that this "power" is calculated as R*Ieff^2.</p> <p>But I want to know if there are some explanation in the reference maunual book. I have checked but didn´t find any explanation.</p> <p>It would be highly appreciated if someone can help me with this problem.</p> Tue, 16 Jan 2018 10:53:54 +0000 4.2018-01-16 10:53:54.163811 Winding Direction in Coil Geometry https://www.comsol.com/forum/thread/163771/winding-direction-in-coil-geometry?last=2018-01-15T14:06:53Z <p>Hi,</p> <p>After drawing a chunck block, I set this block as a homogenized multi-turn coil with circular coil-type. Then I need to select edges with a consistent direction to make it work as the coil.</p> <p>The only problem is, only one edge element shows opposite direction. Does anybody can fix this kind of problem?</p> Mon, 15 Jan 2018 12:49:17 +0000 4.2018-01-15 12:49:17.163771 How to describe the influence of temperature to piezoresisitive effect https://www.comsol.com/forum/thread/163743/how-to-describe-the-influence-of-temperature-to-piezoresisitive-effect?last=2018-01-15T07:32:28Z <p>Hi</p> <p>I want to find out the sensitivity of my piezoresitive strain gauge. In order to do that, based on the application:"piezoresistive pressure sensor".The expression of conductivity is sigma0(nd[m^3]).It makes me wonder and has no clue to understand this.I guess this is a default variable of comsol. My question is that : I want to add the heat transfer in solids interface to piezoresistive effect . How should I acquire that? Since here is the matrix that is defined by comsol : {58.8e-11[1/Pa]/sigma0(nd[m^3])[S/m], -27.2e-11[1/Pa]/sigma0(nd[m^3])[S/m], 58.8e-11[1/Pa]/sigma0(nd[m^3])[S/m], -27.2e-11[1/Pa]/sigma0(nd[m^3])[S/m], -27.2e-11[1/Pa]/sigma0(nd[m^3])[S/m], 58.8e-11[1/Pa]/sigma0(nd[m^3])[S/m], 0, 0, 0, 85.9e-11[1/Pa]/sigma0(nd[m^3])[S/m], 0, 0, 0, 0, 85.9e-11[1/Pa]/sigma0(nd[m^3])[S/m], 0, 0, 0, 0, 0, 85.9e-11[1/Pa]/sigma0(nd[m^3])[S/m]} However, how should I set if I also wanted to make the conductivity a function of temperature. Or how to add the temperature coeffcient of resistance in material properities.</p> <p>Best Regards Sheng Qu</p> Mon, 15 Jan 2018 07:29:12 +0000 4.2018-01-15 07:29:12.163743 Coordinate system and axis orientation in 3D cut plane https://www.comsol.com/forum/thread/163722/coordinate-system-and-axis-orientation-in-3d-cut-plane?last=2018-01-14T19:52:42Z <p>Hello Sometimes when you do a 3D cut plane on a geometry, COMSOL shows you the local coordinate system and axis orientation of that cut plane, see attachment 2. And sometimes it does not show, see attachment 1.</p> <p>My 2 questions are: 1) How can i make COMSOL always show that local coordinate system and axis orientation in a cut plane? 2) How can i change the axis orientation of that local coordinate system?</p> <p>Thank you</p> Sun, 14 Jan 2018 19:52:42 +0000 4.2018-01-14 19:52:42.163722 Directional antenna transmission in 2D https://www.comsol.com/forum/thread/163712/directional-antenna-transmission-in-2d?last=2018-01-14T18:43:02Z <p>What is the simplest way to do a 2D simulation for a directional antenna? Also how can we check the transmiision through different materials?</p> <p>Thanks in advance, ZH</p> Sun, 14 Jan 2018 15:57:34 +0000 4.2018-01-14 15:57:34.163712 parametric convert to solid https://www.comsol.com/forum/thread/163702/parametric-convert-to-solid?last=2018-01-14T10:06:42Z <p>Hi</p> <p>I don't know why I can't convert the parametric surfaces into a solid. I can see that comsol still think it is a surface. could someone please help me.</p> <p>your help is truely appreciated</p> <p>best regards</p> <p>RH</p> Sun, 14 Jan 2018 10:06:42 +0000 4.2018-01-14 10:06:42.163702 How to model wind turbine simulation in Comsol? https://www.comsol.com/forum/thread/163701/how-to-model-wind-turbine-simulation-in-comsol?last=2018-01-15T21:06:54Z <p>Hello, I want to simulate a wind turbine for a competition, but i constatnly keep running into probems. I want to define the pivot of the turbine geometry but the closes solution i came across is using Rigid Connector, but every time i try to compute i get an error message saying that the Nonlinear solver hadn't converged. Can someone help me fix this issue or propose another solution for modeling wind turbines in Comsol. I have to finish this part of the project really soon because I have a deadline for it. Thanks in advance. Best regards. Uros.</p> Sat, 13 Jan 2018 14:48:38 +0000 4.2018-01-13 14:48:38.163701 Thermal Expansion 2D don't agree with analitical value of 3D https://www.comsol.com/forum/thread/163682/thermal-expansion-2d-don-t-agree-with-analitical-value-of-3d?last=2018-01-16T00:28:13Z <p>Hi,</p> <p>I've been using the 2D Thermal Expansion Module to verify some results. I've built a copper bar with 300<img class="latexImg" src="data:image/png;base64,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" /> x 10<img class="latexImg" src="data:image/png;base64,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" />x3.5<img class="latexImg" src="data:image/png;base64,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" /> (The 3.5<img class="latexImg" src="data:image/png;base64,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" />was put on thikness of solid mechanic module). It shows that the displacement was 5.2<img class="latexImg" src="data:image/png;base64,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" /> when subjected to an enhance of 800K. The theoric value gives <img class="latexImg" src="data:image/png;base64,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" />. This is a diference abaut 30%, even thoug it is a very simply simulation. But if I simulate the same values for a 3D sistem, the result agree with theory. Why is there this difference? Is it possible that I've been using the of displacement measurement wrongly?</p> <p>Thanks and best regards</p> <p>Gabriel Gama</p> <p><img src="http://" alt="https://drive.google.com/open?id=1fpRo2YUGzLP_6pEzkgatqxFobOLdtT3-" /> <img src="http://" alt="https://drive.google.com/open?id=1eAWI9lId5ZE1Am88VwszdIX9NqewXKYH" /></p> Sat, 13 Jan 2018 01:59:05 +0000 4.2018-01-13 01:59:05.163682 Save a model as older version https://www.comsol.com/forum/thread/163681/save-a-model-as-older-version?last=2018-01-16T10:38:50Z <p>Hi,</p> <p>Is it possible to save a model as older version? I have 5.3 and I would like to save model for previous vesion, e.g. 5.2.</p> Fri, 12 Jan 2018 21:54:24 +0000 4.2018-01-12 21:54:24.163681 Unable to replicate results from COMSOL 4.4 onto 5.3 https://www.comsol.com/forum/thread/163671/unable-to-replicate-results-from-comsol-4-4-onto-5-3?last=2018-01-12T16:03:25Z <p>I am trying to simulate electrical field in 2D with a rotating source.</p> <p>I setup the model some times ago and working with the expected output.</p> <p>I tried running the same model in COMSOL 5.3. The electric potential surface plot is correct but the probe table plt is completely wrong.</p> <p>I rerun the same file in COMSOL 4.4 and getting the correct results.</p> <p>I have attached the results here and the model file (Comsol 5.3).</p> <p>Thnaks for the help.</p> Fri, 12 Jan 2018 13:43:41 +0000 4.2018-01-12 13:43:41.163671 Acoustic/Structure Multiphysics in Vaccums https://www.comsol.com/forum/thread/163651/acoustic-structure-multiphysics-in-vaccums?last=2018-01-12T11:37:22Z <p>Hello, First time posting here so please be nice! I have looked at previous posts, and skimmed the COMSOL manual but haven't managed to find the answer to my question.</p> <p>When modelling a rigid scattering object in an acoustic field, I am aware you can simply subtract the volume of your scatterer from the your external fluid (as is done in the scattering tutorial); so effecively COMSOL is treating the boundary between a fluid domain and a 'non-fluid' domain as a rigid boundary.</p> <p>Is the same true with the structural modelling? For example, I have a model of a hollow cylinder in an external fluid of air, excited by a structural force. I want to compare this to the same cylinder and excitation, but in a vaccum. Can I simply remove the air domain, and COMSOL will therefore assume that the cylinder is invacuo?</p> <p>Thanks in advance for your help, Charlie</p> Fri, 12 Jan 2018 11:37:22 +0000 4.2018-01-12 11:37:22.163651 Value determination for 'wavelength' and 'search for modes around' field https://www.comsol.com/forum/thread/163641/value-determination-for-wavelength-and-search-for-modes-around-field?last=2018-01-12T09:24:50Z <p>I am currently working on Surface Plasmon Resonance based Photonic Crystal Fiber Biosensor which consists of air holes with silica background,gold layer and liquid analyte channel.In case of mode analysis, how I should determine the wavelength at which light will pass through the core.Is there any way to determine the wavelength ? And in the "search for modes around" field, what value should I put?</p> Fri, 12 Jan 2018 09:24:50 +0000 4.2018-01-12 09:24:50.163641 Tangential derivatives in cylindrical coordinates https://www.comsol.com/forum/thread/163612/tangential-derivatives-in-cylindrical-coordinates?last=2018-01-11T20:35:15Z <p>The below post is related to an <a href="//www.comsol.com//forum/thread/19980/better-understanding-of-the-test-function">archived discussion</a></p> <hr /> <p>Hello,</p> <p>I am trying to write the surface gradient (i.e. tangential derivative) of test function in cylindrical co-ordinates.</p> <p>I wrote : (test(uTr)+test(vTphi)+test(wTz)) and got the error: "undefined variable vTphi.</p> <p>I know that the formulation is (test(uTr)+test(vTy)+test(wTz)) in cartesian co-ordinates. I am trying to write the analogue of the expression in cylindrical co-ordinates.</p> <p>Could someone help me with this?</p> Thu, 11 Jan 2018 20:35:15 +0000 4.2018-01-11 20:35:15.163612 Need help: COMSOL Optimizer under different components https://www.comsol.com/forum/thread/163602/need-help-comsol-optimizer-under-different-components?last=2018-01-11T20:30:10Z <p>Hello,</p> <p>I am having trouble using the COMSOL optimization module to solve for a kinetic parameter in a converged model while fitting measured data.</p> <p>I have a converged model with a 1D fluid phase component and a 2D particle/porous component set up. I am trying to optimize a parameter under the particle component to fit experimental data measured under the fluid phase component.</p> <p>I set up the optimizer least square objectives with attached data csv file under the fluid phase component and the global control variable for the parameter desired to be optimized. I run into an error message **“Undefined function at the initial point. Returned solution is not converged”. **</p> <p>Has anyone done anything similar to this? Am I missing something setting it up or attaching the data?</p> <p>Thanks,</p> <p>Gary</p> Thu, 11 Jan 2018 19:53:24 +0000 4.2018-01-11 19:53:24.163602