December 26, 2013. Study step. Starting with the initial guess U0, the software forms the linearized model using U0 as the linearization point. The COMSOL Multiphysics Reference Manual describes the core physics interfaces and functionality included with the COMSOL Multiphysics license. Opening Topic-Based Help 4 | CONTENTS model.form() . We will cover the most important numerical methods and underlying algorithms used for . . . . Conclusion of the Solver Blog Series. When your solution dose not converge it typically because of : 1. . (Frequency Domain should be the last step . Right-click on the Stationary Solver node and add either the Segregated or Fully Coupled feature. I'm trying to model a solid that's moving through a steady background field in a background flow, I want to take into account the effect of movement of the solid after each time step so I have to use stationary solver after each time step in order to see how field has changed after solid moved. A Stationary study step is intended for a stationary or steady-state situation where you can use a stationary solver. Syntax. This course is intended for people who seek to analyze computational models with non-linear solutions and/or large numbers of degrees of freedom using COMSOL Multiphysics. In COMSOL Multiphysics, a stop condition can be added to the following solvers: Time-dependent solver. . Maximum number of Newton iterations reached. Die COMSOL Vertriebs- und Support-Teams stehen Ihnen für alle Fragen zur Verfügung, die Sie . STATIONARY SOLVERS Wednesday October 4, 1:30. . P&S Comsol Team: Arif Güngör , Yannik Horst , Stefano Valente. Stationary solver with a parametric or auxiliary sweep. 1200 1100 1000 goo 800 700 600 500 400 300 0.005 Line Graph: Temperature (K) 0.015 (m) 0.02 20 s 40 s 60 s 80 s 100 s 120 s 0.025 0.01 Instruction for the Solver Settings for COMSOL Multiphysics course will be performed by experienced engineers who use COMSOL Multiphysics on a daily basis to solve a wide range of complex multiphysics problems. (ewfd) + Stationary Solver + Batch Sweep o 5 cores/parameter solution o Time steps taken over the range: o Single parameter solver time: ~15min . It controls the. . . As we expect, within the gap between two parallel . y default, the plot of the Electrostatic Potential is shown. . But I cant get a solution using the Stationary Nonlinear Solver: Failed to find a solution: No convergence, even when using the minimum damping factor. It is critically important in dealing with chemical reactors, heat exchangers, blood flow and a host of other phenomena. Common Mistakes: Not assigning materials to all the domains. Issues such as meshing, accuracy, and convergence have been covered. . For a description of the nonlinear solver see the entry under coupling. . This solver is automatically used when a Stationary or Frequency Domain study is added to the model. . . Problem Geometry is just a square. . Within either of these features, it can also be helpful to enable the Results While Solving option, as shown in the screenshot below, to visualize the iterations being taken during the solution. . The stationary solution can be used as the initial values for the time-dependent solver, according to the given instructions. . . Stationary study uses Fully Coupled solver to handle the large amplitude of absorption coefficient'svariation with temperature (()) COMSOL . Frequency-domain solver. If you need some additional help, please contact me. If I right-click in "Stationary solver 1" and click in "Fully coupled" then the solver doesn't converge. . Very impressive review of how to solve the COMSOL Multiphysics problems more effectively. It solves the discretized form of the linearized model f' (U0) δU = −f(U0) for the Newton step δU using the selected linear system solver ( f' (U0) is the Jacobian matrix). Browse our knowledge base now. In electromagnetics, it is used to compute static electric or magnetic fields, as well as direct currents. . . What to do when a linear stationary model is not . Of course, it is always instructive to go into the solver settings to see what settings the software has chosen. 99 This series of postings has been designed to give you an understanding of the algorithms used in COMSOL to solve single-physics and multiphysics linear and nonlinear steady-state problems. This book also has instructions about how to use COMSOL Multiphysics and how to access the electronic Documentation and Help content. Not assigning proper boundary conditions: Especially if you have ports. kindly can any one help me out . Analysis type. Solver. This solver uses a nonlinear solver if nonlin is on, and it uses the linear solver if nonlin is on or linper. pressure: P1+P1 (the default), P2+P1, or P3+P2. Returned solution has not converged. Mesh ; Try to improve your mesh quality base on your geometry and your problem. . Wrong ordering of study steps. Try to: 1) launch the simulation up to lambda=500 or until the sweep correctly works; 2) add a secondary study taking the solution from the previous one; 3) increase the mesh resolution and solve . Frequency-Stationary; Sequential Frequency-Stationary (one-way coupled electromagnetic heating) Sequential Frequency-Transient (one-way coupled electromagnetic heating) Frequency-Transient. This solver is automatically used when a Stationary or Frequency Domain study is added to the model. This issue has been fixed in Update 4 for COMSOL Multiphysics 5.4. . Researching a New Fuel for the HFIR: Advancements at ORNL Require Multiphysics Simulation to Support Safety and Reliability. Stationary The Stationary () study and study step are used when field variables do not change over time, such as in stationary problems. . The Graetz problem is a fundamental tube flow problem that couples fluid flow with heat and/or mass transfer. This will use the initial conditions you specified in your physics setting (usually 0 is used in the physics settings). P&S Comsol Team: Yannik Horst, Manuel Kohli, Xinzhi Zhang. Also see About the Stationary Solver for information about Damped Newton Methods . . . - Feature: Stationary Solver 1 (sol1/s1) discretization (the element types used in the finite element formulation). . The other one is to add solid-state HDD and configure it as virtual memory. I am trying to solve the coupling between a waveguide and a microring resonator. If I right-click in "Stationary solver 1" and click in "Fully coupled" then the solver doesn't converge. Here are two things I am concerned and would like to follow up based on your posts: . . Graetz. WELCOME TO THE COMSOL CONFERENCE 2017 Over the course of 3 days, expand your skills . . . . Use the Stationary Solver () to find the solution to linear and nonlinear stationary problems (also called static or steady-state problems). . This chapter introduces you to the capabilities of the module including an Posts: n/a Hello World. . Stationary. Conclusion of the Solver Blog Series. . If your matrix is singular than no solver in the world can solve Ax=B. 2. but there is only one variable in all the segregaetd groups! "- Feature: Stationary Solver 1 (sol1/s1) Failed to find a solution. As you can see in the model attached, (COMSOL 4.4 , 2D axial . The equation for the eigenvalue is therefore a normalization of the electric field, so the average field is unity over the domain. The Comsol module sphere is designed to solve this problem numerically. This series of postings has been designed to give you an understanding of the algorithms used in COMSOL to solve single-physics and multiphysics linear and nonlinear steady-state problems. This is currentiter, using this varable you can recalculate the correct time. The "Values for dependent values" in study step settings should be set to the default ("Physics-controlled" in 5.2). To display this section, click the Show button and select Discretization. . Common Mistakes: Not assigning materials to all the domains. Results and Discussion The solidification front computed with the coarsest mesh, and for T = 75 K, is shown Get expert help with questions and issues related to COMSOL Multiphysics software. . stationary solver; end for; What we need is the for-loop counter to recalculate the time (start, end) for the transient solver. Last time step is not converged. 98 It will run faster then regular HDD for sure. Click on ^ ompute _. Comsol starts with the simulation and then the result appears in the ^Graphic window. response to the increasing awareness of the risks associated with the proliferation of nuclear materials, the Global Threat Reduction initiative has called for research . . To display this section, click the Show button and select Discretization. . How to contact COMSOL: Benelux COMSOL BV Röntgenlaan 19 2719 DX Zoetermeer The Netherlands Phone: +31 (0) 79 363 4230 Fax: +31 (0) 79 361 4212 info@femlab.nl www.femlab.nl Denmark . Hello guys. . . . . BCs ; use consistent BCs according to your . . Stationary in the COMSOL Multiphysics Programming Reference Manual Damped Newton Methods The nonlinear solver uses an affine invariant form of the damped Newton method as described in Ref. 25 K. The double-dogleg solver is used to find the solution to this highly nonlinear problem. Near the top of the Stationary Solver log, the software will report if a linear or nonlinear solver is being used. You also need to defined initial values for T and h. Solve the system of ODEs using a Time Dependent study, where you define the range for the time stepping. . Table 6-160: Properties for Results While Solving. . In heat transfer, it is used to compute the temperature field at thermal equilibrium. The first step is to define a scalar that we can use in a relational or logical expression. . Use the Stationary Solver () to find the solution to linear and nonlinear stationary problems (also called static or steady-state problems). From the Discretization of fluids list select the element order for the velocity components and the. . comp1.u2, comp1.v2, and comp1.w2 are usually variables associated with the x,y, and z component of deformation in COMSOL. using COMSOL's syntax where Tt = dT/dt etc. . . When running large models on a cluster with COMSOL Multiphysics 5.4, the MUMPS solver hangs or crashes. Select a solver (stationary, time dependent etc) Visualize the results after the simulation is complete; Since in the comsol user's guide, I was not able to find examples which exploit this type of solver. . . . Another problem is that, if one does so, it seems that the transient. . COMSOL . . The Stationary Segregated Solver Algorithm . Stationary solver with a parametric or auxiliary sweep. The following properties are available. In order to calculate the capacitance matrix in the Electrostatics interface, we set a terminal condition to one sphere with a potential of 1 V. Next, we duplicate the feature, apply it to the second sphere, and set the terminal name to 2. The course will occur in a live, interactive, web-based format July 13-15, 2021 from 1:00pm - 3:30pm EDT. . . In COMSOL Multiphysics, a stop condition can be added to the following solvers: Time-dependent solver. . The first step is to define a scalar that we can use in a relational or logical expression. . On. Previously in our weak form series, we discretized the weak form equation to obtain a matrix equation to solve for the unknown coefficients in our simple example problem.Following the same procedure as in this previous blog post, we will implement the equation in the COMSOL Multiphysics® software with additional steps included to examine the matrices. but there is only one variable in all the segregaetd groups! . . It then computes the new iteration U1 = U0 + λ δU . Showing results 41-60 of 1,349. . -Detail: NaN or Inf found when solving linear system using SOR. COMSOL Multiphysics ® designed to assist you to solve and model low-frequency electromagnetics. . My questions are: Why is there a problem in the 1rst place? I have tryed to put all the variables from the segregated groups in just one. singular matrix! Expand the Solver Configurations and Stationary Solver nodes (for transient models, this would be the Time-Dependent Solver node) Here, you will see the solver in use (enabled and typically called Suggested Direct Solver (tag)) You will also see the Suggested Iterative Solver (description) (tag) that is disabled (there may be more than one) Singular matrix." Possible Solutions: Not entering required material parameters. Stationary Solver. Transient. I have tryed to put all the variables from the segregated groups in just one. Although it takes more time, this solver converges better in cases when material properties vary strongly with respect to the solution. COMSOL Search. This discussion relates only to stationary, time-invariant, problems. . COMSOL . Through a better . 4 | CONTENTS model.geom() . Not entering required material parameters. stationary state. Note: This discussion is about an older version of the COMSOL Multiphysics . This scalar can either be a quantity defined at some point of interest . The problem is solved as a stationary one though it is set up to be able to solve as a transient problem if you wish. What the stationary study does is to calculate the 'final' temperature. The colored surface in Figure 1 represents the velocity profile while the solid, black line is the thickness of the thermal boundary layer defined as the point where the temperature is 99% of the free stream temperature. I have searched all over comsol forum to fix this stationary solver configuration and still doesn't work because I don't know the logic behind the solver system. . Define G, F, and C as Global Parameters, and define H, Ys, B, and Qg as local Variables, which can be functions of T and h and the parameters. A zero row means a zero on the diagonal which means. Stationary vs time-dependent; Diagnosing solver errors; Interpreting convergence plots and log data; Instructors. discretization (the element types used in the finite element formulation). COMSOL . . Learn all the important working, principles, features, conditions on which COMSOL Multiphysics AC/DC module works. You have to take care, that the transient solution runs using the stationary solution. A nice aspect of it is that there is an analytical solution to the problem for laminar flow, both . 1 → expand ^Stationary Solver 1 _ → click on ^Direct → in ^Setting _ window → change the ^Solver _ into PARDISO. 1 Reply Last Post Oct 20, 2012, 6:37 a.m. EDT. . . The problem is that when I run my model this message appear: Undefined value found. . (Although frequency-domain problems can also be treated as stationary in that they assume a . . - Feature: Stationary Solver 1 (sol1/s1) The following feature has encountered a problem: - Feature: Parametric 1 (sol1/s1/p1) Parameter list gives empty sweep. "out of memory in stationary solver". . representative, go to other COMSOL websites, request information and pricing, submit technical support queries, subscribe to the monthly eNews email newsletter, and much more. However, it is possible to solve a nonlinear problem with the stationary solver, using the eigenvalue as an unknown. In addition to conventional physics-based user interfaces, COMSOL Multiphysics also allows entering coupled systems of partial differential . Most multiphysics problems are nonlinear. . . . The cost for this course is $800 USD per person. . . The figures below show the result of a simulation in Comsol. Joke Lee . From the Discretization of fluids list select the element order for the velocity components and the. . COMSOL Multiphysics is a finite element analysis, solver and simulation software / FEA software package for various physics and engineering applications, especially coupled phenomena, or multiphysics. The other one is empty. 504 The Adaptive Solver Algorithm . You can write the discrete form of the equations as f(U) = 0, where f(U) is the residual vector and U is the solution vector. . . One of the questions we get asked often is how to learn to solve multiphysics problems effectively. How to solve "Feature: Stationary Solver 1 (sol1/s1) Attempt to evaluate nonintegral power of negative number." Posted 14 янв. These posts are designed to give you an understanding of the key concepts behind . . My questions are: Why is there a problem in the 1rst place? pressure: P1+P1 (the default), P2+P1, or P3+P2. . Auto select solver. . . This scalar can either be a quantity defined at some point of interest . . We can safely set N to 10 for a given set of parameters: a = 0.1, b = 0.3, and c = 0.5. Not meshing all the domains. After passing the model in unsteady state, now I have problem with the time-dependent segregated solver. in numerical simulation. On the other hand, a transient study lets you see all the transformation from your initial study until it reaches an equilibrium of sorts i.e. . This is for COMSOL 5.2, but should be similar for 4.2: Create the stationary study. Expand the Solver Configurations and Stationary Solver nodes (for transient models, this would be the Time-Dependent Solver node) Here, you will see the solver in use (enabled and typically called Suggested Direct Solver (tag)) You will also see the Suggested Iterative Solver (description) (tag) that is disabled (there may be more than one) . . I use comsol multiphysics 5.2a and . Frequency-domain solver. If nonlin is set to auto an analysis is performed to automatically detect if the problem can be solved with a linear solver approach. . . COMSOL Multiphysics: Nonlinear solver did not converge. Particularly, I was able to obtain the convergence with a stationary segregated solver. Ivar Kjelberg "Retired" but still part time CSEM SA (CH) Send Private Message Flag post as . Another Problem with COMSOL. . Over the last several weeks, I've been writing a series of blog posts addressing the core functionality of the COMSOL Multiphysics software. Stationary: Auto select solver: On: Solver: Parametric . . . Among the instructors . Solver Selection with COMSOL #1: S. Gatzka Guest . Conclusion Through the use of COMSOL as a design/characterization tool, we successfully variants of Harvard's seminal metasurface design [1-4], and validated the future use of I am following the same model as Comsol provide us on the web. It will be slow but the case should be kept running. The other one is empty. . . In this minicourse, we give a top-down view of studies and solver settings. This blog is a good start to understand what the module is capable to do in terms of simulations. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

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