Comsol if statement Aug 7, 2015 · Hello everyone İ want to make a boundary condition for a density change according to temperature on the surface. EST Low-Frequency Electromagnetics, Materials, Modeling Tools & Definitions, Parameters, Variables, & Functions Version 5. Feb 22, 2011 · conditional expression "if" Posted Feb 22, 2011, 9:36 a. Sep 23, 2025 · COMSOL 中的周期性条件与对称性条件对称性条件周期性条件 个人理解： 周期性条件：源边界与目标边界场值之间的关系，比如相等、相反、相位差等等；涉及两个边界。 对称性条件：边界法向上场值为0；涉及一个边界。 对称性条件 COMSOL 不同的物理场模块有内定的对称性条件，也可以手动设定 learn comsol multi physics with quality tutorials and resources in our channel. 🧬Available for . The example that I mention would consist of simulating a loss of mechanical properties when the Von Mises stress is very high in a model. Settings Aug 30, 2015 · Hi, I am a complete beginner in COMSOL and I am wondering how to include an if statement in material properties. May 23, 2024 · Hello COMSOL Community, I am working on a COMSOL model that involves multiple geometric components, and I want to create a flexible simulation where users can choose which components to include or exclude before running the model. IF statement mainly has three types based on its usage in the COBOL program: Simple IF: Simple IF is mainly used to execute the condition related code. The coordinate columns’ titles contain the space variable names from the dataset, if you use a Cut Plane dataset All Expression fields supports tensor variables and operators for tensors. Click the Active button to toggle between turning ON and OFF the Input objects selections. Work Plane Operations If condition statement is used to check for a condition if a condition is true, the IF block is executed, and if the condition is false, the ELSE block is executed. Apr 16, 2015 · If I am not mistaken the "If" statement exists under the "Geometry" branch of the model tree. My goal is to allow users to control these options via the Application Builder interface. To add this node, right-click the Parametric Sweep (Job Configurations), Batch (Job Configurations), or Sequence node and select it from the Other submenu. Jul 5, 2012 · IF statement in Bondary Condition Posted Jul 5, 2012, 12:31 p. The Thermal Microactuator Simplified model in the Multiphysics section of the COMSOL Multiphysics Application Library uses If and End If nodes in its geometry sequence to consider different geometry cases. Aug 30, 2015 · Hi, I am a complete beginner in COMSOL and I am wondering how to include an if statement in material properties. The Method Call node () runs a model method defined in a Method Call node under Global Definitions (see Method Calls). 4, Version 5. In order to make it possible for this small group to service the much larger group, the Application Builder offers a solution. 3a 0 Replies May 6, 2013 · Question about "if" function Posted May 6, 2013, 11:44 a. Apr 4, 2025 · Introduction to Fab Central. Learn Conditional Statements Within An Expression in COMSOL Multiphysics. If the condition is true, then it will execute the set of statements written in Dec 9, 2023 · I'm chaining two time-dependent simulations, the first one finishing on a stop condition and yielding the solution, say 'sol 1'. A number of tools and resources are available to help you automatically COMSOL Multiphysics reports problems of two types: errors and warnings. And I need to set the Dirichlet boundary condition on a face. It enables simulation experts to create an intuitive and very specific user interface for his or her otherwise general computer model — a ready-to-use application. Browse the threads and share your ideas with the COMSOL community. This section contains simple examples of some of the most common language elements. 2 Posted Nov 9, 2011, 1:33 a. comsol Flux boundary condition in solute transport. One way to do this is by using the up and down operators. Running the COMSOL Installer The steps for running the COMSOL Installer are independent of the installation media option you used. EST Heat Transfer & Phase Change 2 Replies Apr 12, 2011 · if condition in variable definitions Posted Apr 12, 2011, 10:36 a. Does anyone know how to do this? Best regards! Christian Edit: Removed typo in title In the COMSOL Multiphysics environment, you use the Java® programming language to write methods, which means that you can utilize the extensive collection of Java® libraries. learn comsol multi physics with quality tutorials and resources in our channel. EST 4 Replies If, ElseIf, Else, EndIf Construct an If statement, enabling or disabling features depending on conditions in terms of parameters. EST Version 4. 5 2 Replies The Semiconductor Module is well documented and includes a detailed outline of the underlying theory on which it is based. What I don't manage to do is to record the value of the last time of simulation 1 and use it as the starting time of simulation 2. [COMSOLインストールフォルダ]\Multiphysics\doc\pdf\COMSOL_Multiphysics\COMSOL_ReferenceManual. Feb 6, 2018 · Hello Dear, I am trying to define if else condition in comsol. For more information and examples, see the Application Programming Guide and the Programming Reference Manual. Jan 28, 2017 · The general syntax for conditional statements is if (condition,true_branch,false_branch). Getting the maximum value is easy, but so far I have not been able to get the coordinates of the maximum, preferably without using Matlab. 6 days ago · The COMSOL discussion forum covers a wide variety of simulation topics. COMSOL ?an integrated simulation environment. İ made a PDE (using heat equation for both i just changed the units for the density) for heat and density one of them calculates temperature and the other uses the results of the first PDE to find density. Either enter the data manually or import it from a data file. This node represents a special type of feature in the Model Builder that you get by default when you add a physics interface. How and where in comsol do I define the following condition attached below? Kind regards, Bright Oct 11, 2018 · COMSOL if statement Posted 2018/10/11 21:06 GMT-7 Structural & Acoustics, Porous Media Flow, Results & Visualization Version 5. These operators are available only on boundaries (that is, geometric entities of dimension one less than the dimension of the model). 1 6 Replies 6 days ago · The COMSOL discussion forum covers a wide variety of simulation topics. Apr 12, 2011 · The time in COMSOL is "t" (in seconds) but it is not formally declared before you call a transient solver, therefore when you mix stationary followed by a time series and you want to debug such a solution with variables depending on "t" these might flag an error. 4. Use Variable name to interpret the value as a variable name according to the rules outlined in Entering Names. Jan 14, 2021 · I keep getting Comsol errors but still want to see and analyze the data before the crash is there some way for me to do this? Would it be possible to put a stop condition in the time dependent stop and not just solve for a final stop time? I am using the battery module and need the model to stop if the voltage gets too high or too low as it crashes the model. Jul 13, 2017 · But it is not. For example, I want the density,p to be dependent on temperature, T such that if T<273K, p=998 and if T>273K, p=1000. These tables list the unary and binary operators (Table 5-1 and Table 5-2), special operators (Table 5-8), mathematical functions and constants (Table 5-6), and physical constants predefined as variables (Table 5-7) that are available in COMSOL Multiphysics. Select a Dataset for the data to compute the maximum or minimum. COMSOL Multiphysics® Modeling in Darcian and Non Darcian. PDT Version 5. " Posted Feb 4, 2013, 8:40 a. 3 1 Reply In COMSOL Multiphysics, you can use Interpolation, Analytic, and Piecewise Functions to specify a material property. If there is no Jul 24, 2015 · the "if statement" in comsol Posted 2015年7月24日 GMT-4 15:19 Microfluidics Version 5. Then use the sections below to specify the geometric entities to split, the expression, and the split condition. If Manual is selected, enter the derivatives with respect to the function’s arguments. (eg. Jan 14, 2021 · Saving data before completion and if statement in time dependent step? Posted Jan 14, 2021, 9:46 p. General 6 days ago · The COMSOL discussion forum covers a wide variety of simulation topics. In a complex assembly, this may require some effort. The Semiconductor Module is well documented and includes a detailed outline of the underlying theory on which it is based. Choose Expression to interpret the value as an expression. This is useful to add a conditional statement in expressions within the software. 1 Select your language for the installation and click Next . In the Initial Values node () you define the initial value for the dependent variable declared in the parent node. 0 1 Reply Wu Zhang Send Private Message Flag post as spam Note that while COMSOL employees may participate in the discussion forum, COMSOL ® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team. If the geometry sequence includes user-defined selections above the Check node, choose Manual to select objects, or choose one of the selection nodes from the list next to Input objects. I have tried multiplying my stop A time-dependent analysis must have appropriate initial conditions. I know how to create and start a new simulation starting from the final state of the latter. May 11, 2020 · In Comsol, if statements are given by inequalities. You can combine numbers, parameters, mathematical constants, physical constants, variables, mathematical functions, unary operators, and binary operators. Introduction to PDE with Comsol. EDT Heat Transfer & Phase Change, Parameters, Variables, & Functions Version 4. EST Heat Transfer & Phase Change, Structural Mechanics Version 5. 67K subscribers Subscribe The COMSOL discussion forum covers a wide variety of simulation topics. Jan 3, 2022 · How can I add these conditions in the heat source section in comsol multiphysics? You could define a function with nested if statements as shown in the attached image. But the boundary condition only would be used under certain conditions. A dependent variable needs an initial value for nonlinear and transient simulations. You can use two nested if ()-calls to express the condition for g above. Feb 8, 2017 · Note that while COMSOL employees may participate in the discussion forum, COMSOL ® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team. EDT Computational Fluid Dynamics (CFD), Materials, Parameters, Variables, & Functions Version 4. You add the functions as subnodes under the Switch node. 2 Posted 2011/11/09 1:33 GMT-5 Version 4. The stack also includes a thin dielectric layer feature, for which is not possible to define the refractive index as "from material". I monitored the values of the if expressions with Point Probe Expressions during the calculation The COMSOL discussion forum covers a wide variety of simulation topics. There can also be information displayed for helping you with your modeling. If there is enough distance before the pillar to accommodate a sub-pillar, then the array of sub-pillars starts before the pillar. Right-click the dataset and select Add Selection. 3 1 Reply The Thermal Microactuator Simplified model in the Multiphysics section of the COMSOL Multiphysics Application Library uses If and End If nodes in its geometry sequence to consider different geometry cases. The language selected is also your default language in COMSOL. A number of tools and resources are available to help you automatically Note that while COMSOL employees may participate in the discussion forum, COMSOL ® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team. See also Nonlocal Couplings and Coupling Operators for information about coupling Aug 30, 2015 · Hi, I am a complete beginner in COMSOL and I am wondering how to include an if statement in material properties. EDT Parameters, Variables, & Functions Version 4. Posted Nov 13, 2013, 1:54 a. g. Oct 12, 2018 · COMSOL if statement Posted 2018年10月12日 GMT-4 00:06 Structural & Acoustics, Porous Media Flow, Results & Visualization Version 5. That is, specify how the surroundings affect the model and not how the model affects its surroundings. Sorry for the lengthy video, but I Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. It is used to evaluate results directly on the solution. I also tried it this way: y = f (x) * (0<x) * (x<1) Here both if conditions are evaluated as 1, resulting in the correct solution y = f (x). A number of tools and resources are available to help you automatically The Java ® programming language is used to write COMSOL methods, which means that Java ® statements and syntax in general can be used. If you have followed the above instructions, the COMSOL Installer should now appear. Feb 21, 2011 · Dear Comsol Community, I am looking for a way to find the location of the maximum of a variable. In most places you can use expressions containing: Mar 26, 2023 · CSDN问答为您找到comsol中如何加入if判断语句相关问题答案，如果想了解更多关于comsol中如何加入if判断语句 matlab 技术问题等相关问答，请访问CSDN问答。 When plotting the maximum and minimum value, an associated table appears in the Table window (underneath the Graphics window if using the default COMSOL Desktop layout). In the Value type list, you choose the type of string data that you enter in the Value field. 0 1 Reply Wu Zhang Send Private Message Flag post as spam The COMSOL discussion forum covers a wide variety of simulation topics. The two types are closely related because in a well-posed model, every flux condition results in some unique values of the dependent variables, and every constraint requires a unique flux to enforce the expected values. Use the Switch node () under the Global Definitions node () to switch between global functions during a solver sweep. The Expression field or list is available for most plot types The COMSOL discussion forum covers a wide variety of simulation topics. EST General, Battery Design, Optimization Version 5. 3b 0 Replies The Usage Condition () node (the icon will vary depending on the type of condition) puts a condition that enables or disables its children. m. Nov 9, 2011 · If else condition syntax in comsol multiphysics 4. Then the geometries under the rest 'else if' statements are assigned a material based on the first if automatically but not always in a right way. Jul 24, 2015 · the "if statement" in comsol Posted 2015年7月24日 GMT-4 15:19 Microfluidics Version 5. These then appear in the Input objects list. pdf すなわち、上の式は、 cCuCl2>10 ならy座標の大きさを、 Feb 8, 2017 · Note that while COMSOL employees may participate in the discussion forum, COMSOL ® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team. İ found out that i can type u (result of the first equation) in the second Aug 1, 2016 · Does anyone happen to know if an "if statement" (conditional statement) can be used in the deformed Geometry for prescribed mesh displacement? Meaning, using the CFD module, the deformed geometry only changes the locations where a certain value of the solution is violated. The COMSOL Multiphysics software uses the derivatives of a function if a variable that depends on the solution is used in a function argument. May 18, 2023 · Hi All, I'm asking for help to know how you can change a property of a model expressed by a parameter (e. Record Name Logical Expressions in COMSOL Lecture 1 #Logic #COMSOL #POS Pioneer of Success 8. The COMSOL discussion forum covers a wide variety of simulation topics. only A>0, the Dirichlet Apr 16, 2015 · Note that while COMSOL employees may participate in the discussion forum, COMSOL ® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team. 3 4 Replies Jul 24, 2015 · the "if statement" in comsol Posted 2015/07/24 15:19 GMT-4 Microfluidics Version 5. You can use the condition in a variety of contexts — for example, for variable definitions under a feature or for solver and mesh defaults. Note that while COMSOL employees may participate in the discussion forum, COMSOL ® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team. See Virtual Geometry and Mesh Control Operations for examples of how to use virtual geometry operations to remove a short edge and to ignore and collapse edges to prepare the geometry for efficient meshing. Now i want to build a sub-pillars based on location of the pillar (s). To add a method, go to the Developer ribbon and click New Method () in the Create Methods section. The software is uniquely transparent because the model equations are always visible. 2, Version 5. Sep 11, 2015 · Dear comsol , i had an array of cylindrical pillar on a surface placed at equal distances, the distance between pillar and edge of the surface depends on the surface dimensions. EST 5 Replies Kevin Delaney Send Private Message Flag post as spam COMSOL Multiphysics provides the solution at that time using interpolation. If you are trying to change your geometry with respect to simulation variable "t", then I would suggest you to use a boundary condition like "Prescribed Displacement". Jan 3, 2022 · How to add a conditional statement? Posted 2022/01/03 6:35 GMT-5 Parameters, Variables, & Functions, Equation-Based Modeling Version 5. In addition to the Java® libraries, the Application Builder includes a built-in library for building applications and modifying the model object. If, ElseIf, Else, EndIf Construct an If statement, enabling or disabling features depending on conditions in terms of parameters. EDT Fluid & Heat, Computational Fluid Dynamics (CFD) Version 4. 1 14 Replies Feb 22, 2015 · if statement Posted Feb 22, 2015, 10:03 a. So in your case, when you have the expression u1>1, this will be equal to 1 when the inequality is true, and 0 when it is not. Java supports the usual control flow statements if - else, for, and while. follow us for more :) Do ️SUBSCRIBE for more quality videos on Research and Engineering. I've tried do define a variable tlast1 with The COMSOL discussion forum covers a wide variety of simulation topics. 0 4 Replies The COMSOL discussion forum covers a wide variety of simulation topics. 1, Version 5. 🧬Available for COMSOL Multiphysics provides the solution at that time using interpolation. You can use the at operator to compare two solutions at different times during results evaluation; for example, at (30,u)-at (20,u) is the difference between the solution at 30 s and the solution at 20 s. The general model can serve as a starting point for several different applications, with each You can use the method editor capabilities in the Application Builder to create methods that you can run to automate or extend operations in the Model Builder tree such as creating a geometry or running some special solver sequence. 5 1 Reply Nov 9, 2011 · If else condition syntax in comsol multiphysics 4. The kind of conditions you can use differ between contexts because some conditions cannot be evaluated in all In COMSOL Multiphysics, by convention, the force acting on the model or the flux into the model is specified. May 21, 2024 · On obtaining time values for specific conditions Posted May 21, 2024, 3:45 a. Aug 1, 2016 · Does anyone happen to know if an "if statement" (conditional statement) can be used in the deformed Geometry for prescribed mesh displacement? Meaning, using the CFD module, the deformed geometry only changes the locations where a certain value of the solution is violated. If you have the CFD Module, the Mixer application’s geometry sequence shows the use of If, Else If, and End If. If the analysis starts with nonzero initial conditions, you would in principle need to derive and input all components of the initial values for all parts of the structure. 0 1 Reply Wu Zhang Send Private Message Flag post as spam To add a Logical Expression node, right-click a 2D or 3D Mesh node (that has an imported mesh) and select Logical Expression from the Partition Entities menu. Use a Logical Expression node () to make a selection of geometric entities based on a logical expression in terms of other named selections. Jan 28, 2017 · Syntax of writing conditional statements on comsol Posted Jan 28, 2017, 12:36 p. If Statement COMSOL. The COMSOL Multiphysics software does not limit the results calculations to predefined quantities; you can plot and evaluate any function by entering the corresponding expression. The switch for functions acts essentially as a switch statement in a programming language; that is, it dynamically chooses one of its underlying branches depending on a parameter that can be controlled from the solvers Feb 4, 2013 · "Error: Duplicate variable name. Young's modulus in Deformable Solid) depending on the COMSOL results. You can use the Language Elements tool to insert template code corresponding to a number of control flow, of or block, statements. This brings me directly to my question: I'd like to calculate the reflection from a multilayer stack with the Ray optics module. You can use several of these operations to also control the mesh. 1 14 Replies Mar 11, 2011 · I want to use and if statement in COMSOL but I need it to have two conditions. Mar 18, 2016 · I'm using Comsol for two years now, mainly for electrical and optical simulations. If you, for example, want the cross product between two vectors, simply type You can use the method editor capabilities in the Application Builder to create methods that you can run to automate or extend operations in the Model Builder tree such as creating a geometry or running some special solver sequence. To construct an If statement, in the Geometry toolbar, from the Programming menu, select If + End If (you can also do this by right-clicking the Geometry node in the model tree and opening the Programming submenu). Which type of condition to use depends on what is known about the conditions at the boundary: if the flux is known, the model computes the dependent variables for you; if the Oct 5, 2015 · Setting If statement in COMSOL ODE Posted Oct 5, 2015, 6:21 p. Modeling Metallic Objects in Wave Electromagnetics. I want to calculate the value of the x coordinate when y = 0 and T=300. EST Geometry, Structural Mechanics Version 4. This adds an If node () and an End If node () after the current node. The table contains the maximum and minimum values along with the coordinates for the corresponding locations. A number of tools and resources are available to help you automatically Feb 8, 2017 · Using the if else condition in COMSOL Posted Feb 7, 2017, 11:47 p. 7 this is in meters, and than control a heater. Furthermore, you have complete freedom to include phenomena that are not predefined in the Module with easy-to-enter user-defined expressions and equations. To compute the maximum or minimum for a Solution dataset, use a Selection to define the geometric entity (point, boundary, edge, or domain) to integrate over. 1 3 Replies Oct 11, 2018 · Note that while COMSOL employees may participate in the discussion forum, COMSOL ® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team. Select Manual to specify the function derivatives with respect to its arguments in a table. In this case, the Young's modulus would go from being the initial to a X% of the Comsol if语句 当然，以下是一份关于在 COMSOL Multiphysics 中使用 if 语句的文档。 COMSOL 是一个强大的多物理场仿真软件，它允许用户通过内置的编程语言（如 MATLAB 函数、Java 和 COMSOL 脚本语言）来定义复杂的条件和逻辑操作。 Select the objects that you want to check in the Graphics window. In the New Method window, specify a method name in the Name Eval is a feature made specifically for users of the COMSOL API and does not appear in the COMSOL Multiphysics GUI. Then, specify the function behavior between data points and The COMSOL discussion forum covers a wide variety of simulation topics. Sep 8, 2024 · 本文详细介绍了COMSOL中if函数的使用方法，包括基本语法、应用场景、使用步骤以及注意事项，并通过示例帮助读者更好地 Feb 23, 2016 · Can anyone help on this please? Basically a thermostat which reads temperature at a coordinate; 0,0,0. Most input fields and tables in COMSOL Multiphysics in addition to numbers accept variable names and mathematical expressions. May 5, 2014 · Conditional Statement with Temperature and time variables Posted May 5, 2014, 5:11 p. 3a 0 Replies May 19, 2014 · I have a difficulty assigning properly the materials as COMSOL only allows me to assign a material to the first if statement. The COMSOL Multiphysics software can evaluate expressions on both sides of a boundary. The option Custom string means that the data can be an arbitrary string. Interpolation Functions can be used to describe material properties that are defined by a table or file containing values of the function at discrete points. Hence, COMSOL returns y=0, which is not correct. COMSOL evaluates the if condition as 0. 2a 1 Reply Mar 28, 2015 · I am using the PDE in COMSOL 4. Dec 31, 2009 · Using "WHILE" and "IF" statements in Comsol Posted Dec 31, 2009, 8:45 a. EDT Modeling Tools & Definitions 2 Replies Nov 13, 2013 · How to remove parts of geometry so that another shape may be inserted in. In the COMSOL Multiphysics environment, you use the Java® programming language to write methods, which means that you can utilize the extensive collection of Java® libraries. 2a 8 Replies Use an Logical Expression Selection node () to make a selection of geometric entities or geometry objects based on a logical expression in terms of other named selections. EST Parameters, Variables, & Functions Version 4.