: Flowchart of the EM induced void simulation in COMSOL. For a thermal only transient analysis, the time step size can be much larger: If there is an event that is trying to be captured, the time step size needs to be small enough to capture the event. Parametric study for transient solution. is the car's mass, v. by Pär Persson Mattsson. Particle Image Velocimetry (PIV) of a backward facing step: - Set-up of the Pulsed laser, Optics, Camera, Oil particles generator and Wind tunnel - Parametric study: magnification factor, laser intensity, seeding density, f#, separation time - Image processing - Measurement of velocity, turbulent intensity profiles, Reattachment length 4. The documentation for each model entry in this library includes a technical background, the model definition, and results. 5 1 2 seconds and you will see better effects. I guess my model maybe a little different. Material properties as. The Comsol Manual say that "When using a time-dependent solver, the graph on the Convergence page shows the reciprocal of the time step size versus the time step. The new pseudo-time stepping method is available for all stationary flow physics user interfaces as well as for fluid-structure interaction. Daryl-Max-well uses an H-formulation with fixed and/or adaptive time stepping. that we intend to make in COMSOL Multiphysics version 4. I'm trying to simulate a biphasic flow with the level set method and I have an issue with time stepping. One of the most. The information provided may be out of date. COMSOL has several types of solvers to choose from. I want to plot the reaction force for all the stored output times, but the interpolation only takes 7 steps of the solution, although the "times" in my time stepping are 0:. Particle Image Velocimetry (PIV) of a backward facing step: - Set-up of the Pulsed laser, Optics, Camera, Oil particles generator and Wind tunnel - Parametric study: magnification factor, laser intensity, seeding density, f#, separation time - Image processing - Measurement of velocity, turbulent intensity profiles, Reattachment length 4. I actually don't mind that the time-steps take longer but the real issue is that the size of the time-steps are extremely small. Sometimes the simulations run away (do not converge) and last for ever with a extremly small time step. COMSOL, COMSOL Desktop, COMSOL Multiphysics, and LiveLink are registered trademarks or trade- † New additional time-dependent solutions operators that you can use for results The new method is enabled by default but you can turn it off in the Time Stepping. That analysis you will do in normal static mode. Time-saving Shortcuts increasing productivity in Comsol for Windows. 02:1” in the Times field of the Time stepping section. Many features of Comsol Multiphysics are not used or needed until you solve two- and three-dimensional problems, and these features are explained in Chapters 10-11 and Appendix D. You can get a sense of the cause of the small time step from the Log output. We do not really have to solve anything here. mphbingeom12. ) The quality of simulation results depends on •the mathematical model and underlying assumptions •approximation type, stability of the numerical. In Comsol model I need to use time-dependent solver. Finding the minimum of the quadratic function, r(u), by the direct method means solving u=K-1b • This is known as Gaussian Elimination, or LU factorization • The numerical algorithms are beyond the scope of this course,. I am trying to implement a step function in my time-dependent problem where I want to lower the temperature of a constant temperature boundary from 40°C to 20°C after 10min (600s) of running the model. Electromagnetics Modeling in COMSOL • RF Module - High-frequency modeling - Microwave Heating • AC/DC Module - Statics and low-frequency modeling - Induction Heating wave but just a uniform time varying electric field l Electrical size 0. geommanager1. 15s but the time step I'm getting is around 0. Try a stepping time much shorterr at the beginning like 0. Numerical methods are described in the context of time- and spatial-discretization methods for the mesoscopic-scale model. Simulation time: 5 years 2. Make sure that you run COMSOL version 5. The mathematical model defined above gives the following numerical model: (3). 3a COMSOL now automatically adapts the type of solver used to the number of finite elements in a model. 160 Pseudo Time Stepping for Turbulent Flow Models. (Computational Science is indeed a "Science" and one has to learn it. mphbingeom7. pdf,CFD Module User´s Guide VERSION 4. so in each step or location of melt COMSOL does the time dependent analysis so just looks like heat source is stayed for long time. 5a, COMSOL 4. a lack of consistency and proposed a new second order time accurate local time stepping scheme. Numerical Study of Navier-Stokes Equations in Supersonic Flow over a Double Wedge Airfoil using Adaptive Grids V. 2a brings a new option for faster computations of certain nonisothermal flow simulations, the ability to easily account for gravity in CFD applications, the option to use the Boussinesq approximation for modeling incompressible nonisothermal flow, and more. You may need to introduce manual time stepping for that. Select “Time Dependent” 3. Power consumption analysis was performed on both the circuits to obtain the average power consumption over a time period for each circuit. PDEs in their weak form in Comsol. They are linear multistep methods that, for a given function and time, approximate the derivative of that function using information from already computed time points, thereby increasing the accuracy of the approximation. 2 with a few exceptions. To modify how the time-stepping methods select the time steps, choose an option from the Steps taken by solver list. In fact the last option is what we suggest in KB1127. The Sound of Melbourne Recommended for you. Out_of_memory_in_Jacobian_computation Last time step is not converged. COMSOL reduces the time step size when it does not converge in the time or spatial domain, or even I believe, if it converges in the spatial domain but requires a lot of iterations. Each region is solved independently with its own time stepping and solution options. Shifting the workload a bit from the time-stepping algorithm to the nonlinear solver has proven to be a more successful strategy, although the nonlinear steps may take a bit longer time, the time-dependent solver shows a better convergence which may overall result in a shorter solution time. equals the wheel radius (0. Discrete Time-Stepping Schemes. 1, and COMSOL 4. Simulation of Turbulent Flows • From the Navier-Stokes to the RANS equations • Turbulence modeling Time step requirement: Δt ~ (Re The (time and space) details provided by DNS are NOT required for design purposes Time averaged quantities are appropriate for engineering purposes Large scale resolution (not to the level of the. 4 Time Stepping. On the Help menu, click About COMSOL Multiphysics to check your version. unknowns was solved using time-dependent direct solver. To correctly solve this problem requires a well posed numerics. 243 or later. 4 , 2D axial symmetry). Over the course of 3 days, expand your skills in numerical simulation. mphbingeom5. The solver is based on an explicit scheme with variable time stepping. We will describe practical aspects of implicit time stepping and address some of the challenges of solving nonlinear problems. then click Time-Dependent Solver 1. mphbingeom11. 2a brings a new option for faster computations of certain nonisothermal flow simulations, the ability to easily account for gravity in CFD applications, the option to use the Boussinesq approximation for modeling incompressible nonisothermal flow, and more. The pseudo time stepping is often necessary to get the model to converge. Is your model taking a long time to solve, and an upcoming deadline is making you nervous? See how to optimize your workflow for complex modeling projects. 161 Wall Functions for Turbulent Flows. Application. I want to plot the reaction force for all the stored output times, but the interpolation only takes 7 steps of the solution, although the "times" in my time stepping are 0:. Introduction. Time Stepping section, and change the Maximum step constraint: from its default value of Automatic to either Constant or Expression, as shown in the screenshot below. It can handle general two- and three-dimensional domains described by isoparametric quad or hex elements. 5a, COMSOL 4. When I set the times (Solver Parameter - General tab) to a great value for the step, the model seems to be ok and the calculation converges, but that means simulating too far regarding the characteristic time of the flow. Jos van Schijndel expert on Computational Science and Engineering (CSE) for the Built Environment at the Eindhoven University of Technology. PDEs in their weak form in Comsol. 5 sec velocity is zero then for next 2 second it is 1 m/s and again zero for next 0. ) In application specific software (e. c) This still appears to explicit time-stepping even in the pseudo-time. 4 , 2D axial symmetry). Reducing the time step is a good strategy when convergence problems would otherwise arise due to some fast change in time. Figure 1: Settings for the time-dependent solver. and half a time step are necessary in equations (10) and (11) just to remind us the physical definitions of E and H, and to remind us that E and H are actually offset by half a cell and half a time step. mphbingeom6. February 6, 2014. Storage requirements are on the order of n*k locations. I interviewed at COMSOL (Burlington, MA (US)) in February 2012. Pseudo-time stepping is a method used for robust convergence towards a steady-state solution for fluid flow. 2a brings a new formulation, improvements to the particle trajectories plot, new turbulent dispersion options, and more. Yours - HotKeysWorld. 5 0 Replies. large 3D nonlinear electromagnetic problems in the time do-main. See the complete profile on LinkedIn and discover Yanzhe’s. 00015 or less. simulated with a cycling step function applied to the top boundary of the model. 4 Locate the Time Stepping section. Most time-dependent problems in COMSOL Multiphysics are by default solved with an adaptive timestepping scheme. But the process has some pitfalls, and this paper there-. COMSOL Ltd. The Time-Dependent Solver offers three different time stepping methods: The implicit BDF and Generalized alpha methods and the explicit Runge-Kutta family of methods. In this case the axis position along which the rotor is really rotating is varying his coordinates at each time step. Pseudo time-stepping, probably better known as pseudo-transient continuation, is the technique of solving for the steady-state solution of time-evolving partial differential equations by setting an initial guess and using a time-stepper to evolve the solution forward. Note that the color of the response curves here is the same as that is used to indicate the three points amongst the 64 points as shown in Fig. Introduction to COMSOL Multiphysics. When I set the times (Solver Parameter - General tab) to a great value for the step, the model seems to be ok and the calculation converges, but that means simulating too far regarding the characteristic time of the flow. I guess it could be done with the Stop Condition in the 'Solvers Parameters - Time Stepping - Use Stop Condition' field. COMSOL's multiphysics module was used These included mesh refinement, time stepping options, using different solvers, and using a different element type. mphbingeom5. However, if you choose a stationary solution type, then pick PARDISO or UMFPACK solvers, this is a fully coupled direct solver, which is the best you can get for full coupling. For time-dependent nonlinear models. After deleting step 3 in study 1 (without changing / resetting the solver) and computing the study afterwards, the solver still has the solving steps inside, which he solves without problems! I get the correct result without errors. 4 Time Stepping COMSOL offers two methods to compute the solution. I am having some trouble with the solver, which is unstable and is outputting values at erratic time steps of the form 0. For x < 0, the function heaviside(x) returns 0:. A drop is considered to contain 1 mmol of coffee and spreads rapidly, on time T. Data are separated by a space. The Optimal Workflow for Complex Modeling Projects on a Deadline. a lack of consistency and proposed a new second order time accurate local time stepping scheme. Divergence in COMSOL. COMSOL WEB SITES Typographical Conventions All COMSOL user guides use a set of consistent typographical conventions. This procedure is commonly called Euler’s method. If a CFD simulation takes 16 days on a single core, adding 32 cores might reduce the simulation time to four hours -- slashing more than two weeks from the schedule. Join us at the COMSOL Conference 2020 Boston for a firsthand look at what is possible with multiphysics modeling and numerical simulation. This will enable more efficient time-step control in the BDF method, especially for highly nonlinear models. Pseudo time-stepping, probably better known as pseudo-transient continuation, is the technique of solving for the steady-state solution of time-evolving partial differential equations by setting an initial guess and using a time-stepper to evolve the solution forward. The time point at which is starts diverging seems random, however does change when timestep and numerical damping is varied (amplification factor for high frequency) in the generalized alpha time stepping method. But it says that the file is either corrupt or not valid. Fast Fourier Transform of the periodic deflection of the flat plate solution from COMSOL. This procedure is commonly called Euler’s method. Sometimes the simulations run away (do not converge) and last for ever with a extremly small time step. Thermal flow is rather complex, and requires very fine mesh, AND very short time stepping, (perhaps try a "intermediate" time stepping and not the defult "free", see solver - tiem steppng su-node) particularly if you are in a turblent mode (or with convection). COMSOL Access is a service we provide to our users and prospects. CFD Module Updates For users of the CFD Module, COMSOL Multiphysics ® version 5. Time-saving Shortcuts increasing productivity in IntelliJ for MacOS. Two physics (transport physics and solid mechanics physics) are included in model to simulate a porous media in solution environment. It is a time-dependent derivative therefore d(A, TIME) is like a cumulative value rather than one time (independent of previous step result) thing. (Computational Science is indeed a "Science" and one has to learn it. On the other hand, the memory requirements of COMSOL Multiphysics® are larger. The fire condition described above was used to obtain transients for 30 minutes duration. Not sure if you find the COMSOL Model Wizard somewhere else, maybe other commercial Multi-physics software but not in the open-source community. Comsol Multiphysics uses the backward differencing method for treating stiff systems (BDF). This is a widely used technique in which space is divided into a discrete grid and the fields are evolved in time using discrete time steps — as the grid and the time steps are made finer and finer,. not, more stringent tolerance for the time-stepping, and/or max time step. Acoustics Module Updates. comsol 流固耦合实例_工学_高等教育_教育专区。 流固耦合 采用任意拉格朗日-欧拉方法，求解流固耦合问题。 模型如下图所示： 上海市徐汇区凯旋路3500号华苑大厦2号楼11层A座 (200030) Tel:021-64391516 Fax:021-6. Last time step is not converged. After deciding to learn Python scripting, did you find it to be challenging and time consuming? 3. (Computational Science is indeed a "Science" and one has to learn it. For some reasons, it just worked sometimes, not every time, and i couldn´t figure out a rule. Pseudo time stepping is used in transport problem to stabilize the convergence toward steady state. Time stepping in comsol multiphysics I would like to know which is the algorithm Comsol uses in order to correct the time step it uses. The times specified in the Times field in the General section are not considered when a time step is chosen. In a single solution, I separate the total time into several time ranges, and I want to set different time steps for different time range, for example, for time range (t1,t2), the time step is dt1, for time range (t3,t4), it is dt2, -----. I would like to be able to use results from the model (global values such as time or from coupling variables) to influence the time-stepping. The pressure I solve for will be the complex pressure, 2 2 pp0 c w 2 00 11 pp0 c w rr Constant density p x y z( , , ) Solved for in Comsol 10 ( , , , ) Re ( , , ) 1. COMSOL does not support GPU computing as of 2017, and we've not yet written documentation for running COMSOL across multiple compute nodes. Would you like to automate a lot of repetitive tasks that have to be performed on a daily basis?. t Time τ Transmissivity Comsol Multiphysics software to solve some problems. Pseudo time stepping is used in transport problem to stabilize the convergence toward steady state. g commercial FEM solvers for engineering problems like crash problems or metal forming) this knowledge is. Most time-dependent problems in COMSOL Multiphysics are by default solved with an adaptive timestepping scheme. 1 the solver sequence is defined by corresponding items of the study subtree. mphbingeom1. Would you like to automate a lot of repetitive tasks that have to be performed on a daily basis?. For this reason, the time-dependent solver only works if I specify a small maximum time step of 20 seconds. I have tried to implement all these but I couldnt' get beyond 1 pulse. Further improvements include an array of new physics features and options as well as new postprocessing tools. Each line represents a given time (h). I love those weeks where I have days in a row that I don't have anywhere to go and I can just stay home. The time discretization is usually done with some type of time-stepping scheme for ordinary differential equations. Since the exact time history of the load is not known, it is difficult to perform a time-dependent analysis. Send Private Message Flag post as spam. mphbinsavepoint1/xmesh1. The Backward Differentiation Formula (BDF) solver is an implicit solver that uses backward differentiation formulas with order of accuracy varying from one (also know as the. Orange Box Ceo 7,198,339 views. The local magnetic field in a Penning–Malmberg trap is found by measuring the temperatures that result when electron plasmas are illuminated by microwave pulses. Comsol can be used to. This chapter introduces you to the capabilities of this module. Is there a way to use the stationary solution obtained in Comsol 4. you need to take care to smooth the step sufficiently and to make sure that the timestepping resolves the smoothed function. Electromagnetics Modeling in COMSOL • RF Module - High-frequency modeling - Microwave Heating • AC/DC Module - Statics and low-frequency modeling - Induction Heating wave but just a uniform time varying electric field l Electrical size 0. 7 GHz cores) were 748 and 647 min, respectively. $\begingroup$ Your question is not well posed: before asking for the time step you should ask for the time integration method used to solve your equations. Suketu Naik. Step completion time (CT) was defined as the time interval from foot liftoff to floor contact as registered by the instrumented contact mat. 15 K (the ambient temperature) and the free end at 274. COMSOL Multiphysics ® version 5. The fire condition described above was used to obtain transients for 30 minutes duration. The variable r is the distance from a certain location, which changes in time. × Warning Your internet explorer is in compatibility mode and may not be displaying the website correctly. ) The quality of simulation results depends on •the mathematical model and underlying assumptions •approximation type, stability of the numerical. 0 3 | FLOW PAST A CYLINDER Results and Discussion Figure 1 shows the flow pattern resulting from the geometry. This time it did something similar to Amir's after nearly 0. Modelling of time dependent heat transfer in a bar using PDE (diffusion equation) in Comsol 5. Du Colonel Roche, 31077 Toulouse cedex 4, France. Tutorial on using Comsol to model Transient Diffusion Nader Al-Bastaki mass transfer problem using finite element analysis by Comsol Multiphysics. Welcome to COMSOL Access. audio All audio latest This Just In Grateful Dead Netlabels Old Time Radio 78 RPMs and Cylinder Recordings. Gopal[1], R. The Sound of Melbourne Recommended for you. 0 6 Replies. This operator allows you to evaluate quantities at the previous time step when using the default implicit time-stepping algorithm. For the simulation of the HTS hysteresis motor, time dependent solver parameter is used. This will be more efficient, since the time step is kept short only when necessary. Finite element and finite volume methods are numerical methods based on discretization of space of the model equations. Is your model taking a long time to solve, and an upcoming deadline is making you nervous? See how to optimize your workflow for complex modeling projects. and it gets even smaller as the fluid flow magnitude increases. Electromagnetic waves scattering off of a nano sphere. mphbingeom2. See the complete. The Backward Differentiation Formula (BDF) solver is an implicit solver that uses backward differentiation formulas with order of accuracy varying from one (also know as the backward Euler method) to five. (1) Change from "free" to "intermediate" time stepping (2) Using a smaller time step so that the transition regions are sufficiently resolved (3) Use a finer mesh. That way I can use what I know will happen in conjunction with the time-dependent solver. They are linear multistep methods that, for a given function and time, approximate the derivative of that function using information from already computed time points, thereby increasing the accuracy of the approximation. Seidman which use implicit time stepping, which is a necessity for e ciently solving PDEs of. mphbingeom11. The mathematical model defined above gives the following numerical model: (3). Comparison with PDE routines in IMSL CNL & FNL, FlexPDE, Comsol If this is your first visit, be sure to check out the FAQ by clicking the link above. equation to simply march forward in small increments, always solving for the value of y at the next time step given the known information. It is a time-dependent derivative therefore d(A, TIME) is like a cumulative value rather than one time (independent of previous step result) thing. g commercial FEM solvers for engineering problems like crash problems or metal forming) this knowledge is. DEVELOPMENT OF GOVERNING EQUATIONS Simultaneous heat and moisture transfer in a porous. The Optimal Workflow for Complex Modeling Projects on a Deadline. Few days after submitting the online application, I received an email from one of their senior application engineers, to schedule a phone interview the next day. They are linear multistep methods that, for a given function and time, approximate the derivative of that function using information from already computed time points, thereby increasing the accuracy of the approximation. they can be used to determine ui,2 at the next level (going one step upward in the diagram), and so on. then for next location of heat box COMSOL again does the time deponent analysis regardless of previous step. For the transient solver to be well behaved requires that changes in a time step dt are made on lengths less than the mesh size. Particle Image Velocimetry (PIV) of a backward facing step: - Set-up of the Pulsed laser, Optics, Camera, Oil particles generator and Wind tunnel - Parametric study: magnification factor, laser intensity, seeding density, f#, separation time - Image processing - Measurement of velocity, turbulent intensity profiles, Reattachment length 4. Numerical Study of Navier-Stokes Equations in Supersonic Flow over a Double Wedge Airfoil using Adaptive Grids V. nl International Conference on Numerical and Mathematical Modeling of Flow and Transport in. The authors' efforts are mostly directed at the improvement of the efficiency of. HAMLab (Heat, Air and Moisture Laboratory) is basically an all-in-one collection of models and tools suitable for MatLab and/or Simulink and/or COMSOL, developed by students and researchers under supervision of dr. Posted 25 juil. Modeling InstructionsIf you are working from the beginning of this example, ignore the. These algorithms choose a time step based upon a user-specified tolerance. I am trying to implement a step function in my time-dependent problem where I want to lower the temperature of a constant temperature boundary from 40°C to 20°C after 10min (600s) of running the model. 243 or later. This is accomplished through explicit updating of the size of the jump in tangential velocities across the fluid-fluid interface by a geometric averaging of this data over the previous. total number of time step=1s/timestep or 20s/time step), it depends on your system and on what you are looking for. 1 Check your version. An energy balance of the solid for a time interval dt can be expressed as: heat transfer into the body during dt = the increase in the energy of the body during dt. $\begingroup$ Your question is not well posed: before asking for the time step you should ask for the time integration method used to solve your equations. Tutorial 1: Heat conduction in a slab 2007 Cornell University BEE453, Professor Ashim Datta Authored by Vineet Rakesh and Frank Kung Software: COMSOL 3. Particle Tracing Module Updates For users of the Particle Tracing Module, COMSOL Multiphysics ® version 5. This metric is the diameter of the largest inscribed circle for a triangle and largest inscribed sphere for a tetrahedron. Further improvements include an array of new physics features and options as well as new postprocessing tools. The time discretization is usually done with some type of time-stepping scheme for ordinary differential equations. In this case the axis position along which the rotor is really rotating is varying his coordinates at each time step. COMSOL Multiphysics is an excellent tool for numerical studies of this type, because it can read-ily implement a point source, has reliable time-stepping, accurate linear solvers, and the process of reﬁning the mesh repeatedly is easily automated through the use of LiveLink with MATLAB. It is a time-stepping based code and does not currently support steady-state solvers, other than steady Stokes and steady heat conduction. Modeling InstructionsIf you are working from the beginning of this example, ignore the. Note that the color of the response curves here is the same as that is used to indicate the three points amongst the 64 points as shown in Fig. Thermal flow is rather complex, and requires very fine mesh, AND very short time stepping, (perhaps try a "intermediate" time stepping and not the defult "free", see solver - tiem steppng su-node) particularly if you are in a turblent mode (or with convection). Application. Is there somebody who can tell me what is the new variable name for the CFL number in Comsol 4. UMFPACK linear solver is used and the time range is (0, 5e-5) with a time stepping of 1e-8. View all study and solver updates here. February 6, 2014. Note: This discussion is about an older version of the COMSOL Multiphysics ® software. The process took 4 days. mphbinsavepoint1/xmesh1. numerical and analytical solution can be obtained by decreasing the time step size. We will describe practical aspects of implicit time stepping and address some of the challenges of solving nonlinear problems. To obtain the fully discretised variational form in space and time, I have to implement a numerical method for evolution Stack Exchange Network Stack Exchange network consists of 175 Q&A communities including Stack Overflow , the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. By then applying a modu-lus over time the equation will cycle from 0 to 1 for 90 days every year. From the Method list, choose Generalized alpha. dt_cfl_g1_ns for geometry 1 and application mode ns (Navier-Stokes). The time-stepping and fast cosine transformed results are shown in (a). I am using MATLAB in conjunction with a finite-element simulation program (COMSOL) that solves for some physics with a time-stepping method. Save and use Keyboard Shortcuts. COMSOL Blog. mphbinsavepoint1/geommanager1. 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. Is there therefore a way to set up the time steps to be saved/calculated depending on a variable? Thanks Stefanie. t Time τ Transmissivity Comsol Multiphysics software to solve some problems. Not sure if you find the COMSOL Model Wizard somewhere else, maybe other commercial Multi-physics software but not in the open-source community. 6 GHz AMD Athlon X2 Dual Core 500 CPU and 2 GB of RAM. In other words, when running the earlier phases I don't want the time step within COMSOL to be too large (maybe around 10-30 seconds), but later when I am looking at jumps of weeks at a time, I would want a much larger jump (maybe around an hour) to avoid having simulations which take forever to run. mphbingeom1. A solid in motion may also be a driving factor for a time step size. I too am modelling a diluted species transport model with a modified navier stokes for flow through a porous media. the coupling of the vacancy flux and the stress equations). For a given step n, Simulink updates y(n) and x(n+1). geommanager1. Yours - HotKeysWorld. Last time step is not converged. Finite element and finite volume methods are numerical methods based on discretization of space of the model equations. The pseudo time stepping is often necessary to get the model to converge. the generated water hammer pulse has a step function like shape. Shows how to build a model step by step. Each year is represented by in total 8761 lines. Is your model taking a long time to solve, and an upcoming deadline is making you nervous? See how to optimize your workflow for complex modeling projects. To use this method for fluid. That way I can use what I know will happen in conjunction with the time-dependent solver. Acoustics Module Updates. The COMSOL discussion forum covers a wide variety of simulation topics. Here an adaptive feedback regulator controls a CFL (Courant–Friedrichs–Lewy) number which is then used for pseudo time stepping. This spatial step size corresponds to 4 steps per ply layer. Doubling the number of cores from 32 to 64 might cut the time in half again – from four hours to two hours. Data are separated by a space. Gobbert, Aaron Churchill, Guan Wang, and Thomas I. Finite element method model, external electrical. Be sure to close all COMSOL Pseudo time stepping is now applied by default for stationary analysis. 6 In the associated text field, type 3. Jos van Schijndel expert on Computational Science and Engineering (CSE) for the Built Environment at the Eindhoven University of Technology. For this reason, the time-dependent solver only works if I specify a small maximum time step of 20 seconds. Do not forget that selecting time stepping (transient) changes the equations of COMSOL (adding the time derivatives) so it's not "just" to replace the time by a parametric variable Good luck Ivar. 15s (which is just as the step completes) the time step size shot down to the 10e-13 range then after a further 10 minutes or so of slowly falling it got stuck oscillating between 6. I applied online. These matrices depend on the solution vector (e. Most importantly, the transition from hexahedral/prismatic mesh types to tetrahedrals is now automated by including pyramid elements. mphbingeom6. COMSOL does not support GPU computing as of 2017, and we've not yet written documentation for running COMSOL across multiple compute nodes. Discussion Closed This discussion was created more than 6 months ago and has been closed. On the Help menu, click About COMSOL Multiphysics to check your version. The aim of this project was to compute the power consumption of a normal CMOS versus a domino logic full adder. Ask Question Asked 5 years, 1 month ago. The local magnetic field in a Penning–Malmberg trap is found by measuring the temperatures that result when electron plasmas are illuminated by microwave pulses. A plate over a 10 turns coil. Each year is represented by in total 8761 lines. Gopal[1], R. but you can not change parametric sweep and time both together. The time-stepping and fast cosine transformed results are shown in (a). By the way, I am a little vague about your suggestion of reducing the tolerance below time step size. I tried using a time dependent expression in the maximum time-step size input but that is not allowed.