comsol variable expression

In order to have access to the Replace Expression dialog, you must have some results. Once youve added this feature, you can define variables on any geometric entity level, including: The settings for this feature are shown in the screenshot below. ), or other global variables. You also need to activate the Equation View from the Show menu in the Model Builder toolbar. Your detailed explaination about the variables relieves my confusion about them a lot. I am only allowed to enter a constant or an expression. Hi You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version Hi, Replace variable with scalar expression. Transforming variables with Jinja2 filters . Operators in COMSOL Multiphysics. A good example of this is the Laser Heating of a Silicon Wafer example from the Application Gallery. Ivar. Young's modulus, E. Poisson's ratio, nu. Adding a Global equation to a PDE in COMSOL Multiphysics, Accumulation of Heat example. listed if standards is not an option). This, however assumes that the variable you are looking for is announced as a postprocessing variable. The variable becomes available for plotting and evaluation after re-computing or updating the solution. Is it the definition/confusion of a global variable, a field variable, a scalar time dependent a scalar alone that is not clear ? Best regards, Michael Rembe. Yes, I mean independent variables in the physics node. Send Private Message Flag post as spam. I'm very new to this software and I'm now looking through the application libraries and tutorials. The new functionality is simply easier to use, as there are far less settings (and especially solver settings) to adjust. Variable in Integration Expression. There is one major exception to the list above: a parameter might be changed by a "parametric Sweep" and therefore might be used to define geometry (while a variable CAN NOT be used to define a geometrical shape. Regarding es.normE: It was missing as a predefined variable in 4.0 but is available in 4.0a. This would be a fine feature to add. The State Variable feature simplifies the tracking of the history of a field over time. Is it the definition/confusion of a global variable, a field variable, a scalar time dependent a scalar alone that is not clear ? Ivar. But when I define a Variable under "global definitions" it doesn't. It is possible, but then you need the syntax mod1.es.Ex etc. If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base. Because It took me some time to sort this out with COMSOL. ExpressionBase. -- Good luck Discussion Closed This discussion was created more than 6 months ago and has been closed. 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 you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help. 0 Replies, Please login with a confirmed email address before reporting spam. Thank you. And the I used definitions -> variables subnode for defining the variable C. I could give also other examples. A model has certain independent variables with which you can define new ones, also applied only in certain domains. integrating over the spatial domain i.e. You also need to activate the **Equation View** from the **Show** menu in the Model Builder toolbar. I have displacement intensity "normD" in my expression list but NOT normE! These variables can also be used to affect other fields, such as material properties, and can thus be used to implement hysteresis into your model. Jinja2 filters let you transform the value of a variable within a template expression. Too bad that comsol does not allow the grouping of user-defined vector component variables. Thank you. After running a simulation for a 3D structure with a magnetic field going in the z (vertical) direction, COMSOL returns the following error: Division by zero. 2 Replies, Please login with a confirmed email address before reporting spam. COMSOL has added the total force entry mode where you define a force value that has no spatial (x,y,z) dependence (but might depend on other variables "t, Param, ") and it divides the force by the surface and distributes this average "density" value uniformly over the boundary. You can use the Find tool (press Ctrl+F), if you have set up all the physics. But there is still a problem. Hi Regarding grouping of vector components: That is something that we will look into. In my understanding: 1) under "Global - Definition - Variables" you define variables that are INDEPENDENT of the spatial dimension (x,y,z) but these variables might be dependent on time or any other (sweeping) parameter "t, Param, freq ), or other global variables. The information provided may be out of date. Your internet explorer is in compatibility mode and may not be displaying the website correctly. Because It took me some time to sort this out with COMSOL. But if I want to make a plot across the entire geometry, I define that in domain 1, C = c1 and in domain 2, C = c2. In order to have access to the **Replace Expression** dialog, you must have some results. So in specific time step of solving u, is the time derivative of variable rho solved by chain rule using time derivative of dependent variable w, or equal to zero since rho is a specific value given w is solved? For example, in this case, the heat capacity can be defined via an if statement as: if(SorL,SolidtoLiquid(T),LiquidToSolid(T)). Variables can also depend on dependent variables (the solution) and their derivatives, and they can have units. Hi Walter, Perhaps you will find your reply if you write this out. This order corresponds to the Gauss Point Data element order. We can track the maximum temperature that the part gets to by defining a state variable MaxT, with an initial value of 0 (or any value lower than or equal to the initial temperature field) and use this variable to store the maximum temperature via the update expression: This if statement evaluates to true whenever, and wherever in space, the temperature field, T, is greater than MaxT, and then MaxT will take on the value of the temperature. What ist the difference between the new state variable and the old previous solution operator, you explained some years ago in a blog post (https://www.comsol.com/blogs/using-the-previous-solution-operator-in-transient-modeling)? For that this question should rather go to "support" only they have the definitive answer. COMSOL offers a whole range of . listed if standards is not an option). The state variable can be updated either before each time step (or parameter step) or after. Now all you need to do is enter sqrt(0.5*(tresca_smld^2+mises_smld^2)) in any of the Expression fields and click OK to see your new stress distribution. Hi, There exists an "if" syntax in variables (at least in 4.2) but this may yield convergence problem, because when your condition switches, your boundary . If I had attempted to type that out on my own I wouldn't have known that. ExpressionBase. Good luck Giulio Remo Cupilari. Hi Ivar, In COMSOL Multiphysics , you can see the underlying governing equations for the physics in a model, as well as the definitions of the variables. You can then find it in the Variables list in the Inner Gimbal-Spinning Disc node's Equation View subnode, where it is described as the z component of the joint axis. -- Overview of Integration Methods in Space and Time, How to Join Solutions in COMSOL Multiphysics, How to Activate Material in Simulations of Manufacturing Processes. Is it a segregated approach? The plot below shows what our results will look like. Velocity expression using local variables, Initial guess leads to undefined function value, How to Use State Variables in COMSOL Multiphysics, Using the Port Boundary Condition in Acoustic Waveguide Models. 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. For plots that take vector inputs you must use the defined variables directly in the edit fields for the vector components. Run a **Get Initial Value** if there is no solution yet. You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version @ Lasse you said for diffusion you have two variable c1 and c2. Posted Nov 24, 2021, 5:11 p.m. GMT+1 Hi, Good luck To implement such a model, we need to introduce a switching state variable to decide if we should be following the lower or the upper branch. COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH), 2 Mesh Adaptation Methods: Enabling More Efficient Computations, Initial guess leads to undefined function value, Velocity expression using local variables. Thank you Magnus!! If I replace "normE" by "sqrt(realdot(es.Ex,es.Ex)+realdot(es.Ey,es.Ey)+realdot(es.Ez,es.Ez))" in the expression field the plot works without error. I use the domstate variable with he computed initial value and then domstate=domstate. you can define a global variable "Length = intop1(1)", as the operator intop1 is defined over a given Domain or Boundary it will give back a volume, surface or respective length depending on your space dimension of the model, and will be defined by default on all entities in your model. set (java.lang.String var, double expr) Sets a variable name and expression. But I still think I didn't understand it right. to access these quantities. Run a Get Initial Value if there is no solution yet. Excellent, this is exactly what I was looking for. You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version We encourage you to try it out and see what other applications you can come up with. Posted Oct 2, 2019, 8:39 a.m. EDT Please contact support@comsol.com and mention this, as we will address it. remove (java.lang.String var) Removes a variable. Ivar, Thanks for the help. Once the option is enabled, youll see a Variable Utilities button within the Definitions ribbon, and a Variable Utilities submenu when you right-click the Component > Definitions branch within the model tree. In this scenario you know that you are looking for the orientation of the axis of Inner Gimbal-Spinning Disc, but not what its variable is called. Comsol is investigating deformation due to gravity. Most variables that you as a user would be interested in can probably be found this way. -- There arent many settings here that we need to look at, but there is a lot we can do with this feature. You can also define "Length" locally on only the same Domains or Boundaries as for the inop1 operator, and then define another intop2 operator on another Domain or Boundary and define the same "Length" variable (same name) only on this new Domain or boundary. How to enable the Variable Utilities option. The use of variables and fields in COMSOL are somewhat tricky/confusing in the beginning, because of the implicit suppression of the (x,y,z,t) writing, these spatial variables are defined by your Entity selection higher up in the nodes. You can use the Find tool (press Ctrl+F), if you have set up all the physics. Ivar. Best regards, Magnus Ringh, COMSOL, Magnus suggestion is the way to go for 'reverse engineering', but what if you were to set up that variable 'theta' without knowing that you were looking for mbd.hgj3.e1z? However, some variables might only be used in the post-processing and be of no specific use in the solving process, unfortunately these are also defined "high" up in the tree, and not under a (logical for me) "Definition node" at the "Results" or "Data Set" level, hence clearly defined as post-processing variables to work on the resulting Data Sets It's the same for node fields where you fill in values or expressions, these are mostly expressed as "densities" to be understood as what applies directly to a dx*dy*dz volume of the Domain entity (respective surface for boundaries) and we humans mostly work in "total field/flux" mode, that is the integration over the selected entities of any density value. Good luck However, it is found that the solutions (such as stress and strain) at previous step cannot be accurately recorded for a model with heterogeneous material properties, no matter what Order you select. For example, I define a physical property like density rho which is only a function of dependent variable w. the time derivative of rho is employed to solve another dependent variable u. an expression V = V0+V1* (x>1) works well for many cases meaning V=V0 for X<= 1 and V=V0+V1 above. Thanks for your help. You probably didn't think of it, but in the expression I just mentioned, sqrt, ^, and even + are all examples of operators. In one of the tutorials I come across, the modelling gyroscopic effect tutorial, there is a section where a variable is defined in the definition section of the model tree, and the expression reads mbd.hgj3.e1z, and I am expected to type this out. So, introduce a state variable, SorL, with initial value of 1 (presuming the material is initially solid) and with the update expression: This nested if statement will switch the value of SorL to 0 if the temperature rises above the upper threshold, and only switch it back to 1 if the temperature drops back below the lower threshold. However, I am still trapped in another puzzle that whether a variable defined under model tree is derived with spatial coordinates or time during time dependent solver. I assume, that the parameter is recomputed every iteration step, but this is not necessary. What is puzzling me is I have seen on some forum discussions, that other people who are plotting field intensity are discussing about a predefined expression "normE". The material property can then be conditional upon the SorL state variable. integrating over the spatial domain i.e. The State Variable feature simplifies the tracking of the history of a field over time. When plotting the MaxT field, keep in mind that these state variables do not keep track of units and that the data, which is stored at the Gauss points, is extrapolated and interpolated over the entire element, so this field can look slightly different from the temperature field, which is stored at the node points and plotted via interpolation. When you then add `mbd.hgj3.e1z`, you will find that it is a variable for the Inner Gimbal-Spinning Disc feature. Hello Dirk, I will make a suggestion to explain this variable in this tutorial example's step-by-step instructions. my understanding is that a Parameter is a "static" variable, define once at the beginning/initialisation of the solver process and not changing during the solver process, while the "variable" (that often is a field over (x,y,z,t) and not a only a scalar or a function of time, or frequency ) is or might change. rename (java.lang.String oldName, java.lang.String newName) Renames a variable without changing the expression or description. Download two of the examples featured in this blog post by clicking the button below. -- Jinja2 includes many built-in filters and Ansible supplies many more filters. I want to solve y for . Using subdomain expression variables makes it easier to enter the subdomain properties of the model. These variables can also be used to affect other fields, such as material properties, and can thus be used to implement hysteresis into your model. Lasse, Hi But is your "u depending on rho" linked to your structural physics ? Suppose that we have a transient model where the temperature is fluctuating in time. Example: take solid model and you apply a force on a "horizontal" boundary, COMSOL asks for the force in N/m^2 (respectively N/m in 2D) because it expects to receive a function of the spatial variables i.e "5[N]+3[N/m]*x" a variable force along the boundary. Happy modeling! In this case, we would want to update the variable after each step. In the current version, you can press Ctrl+Space in the edit fields for each vector component to access user-defined variables. Would you agree with this? This switch can be based upon if the temperature rises above, or falls below, the two marked transition temperatures. I cannot select the variable for plotting and if I write it in the expression field, it is not recognized. In my understanding: 1) under "Global - Definition - Variables" you define variables that are INDEPENDENT of the spatial dimension (x,y,z) but these variables might be dependent on time or any other (sweeping) parameter "t, Param, freq . But it can not find the solution. I am using global equations in Global ODE and DAE module in comsol. This, however assumes that the variable you are looking for is announced as a postprocessing variable. I only have version 4.0 but I tried it nevertheless. -- If I input the Young's modulus of the channel to about 1 [GPa], the . Best regards, Dinh An In order to have access to the Replace Expression . Magnus suggestion is the way to go for 'reverse engineering', but what if you were to set up that variable 'theta' without knowing that you were looking for mbd.hgj3.e1z? donate and download files in full HD here:http://www.soft-hummingbird.com/Tutorial_Comsol_Download_DonateThis is a tutorial for COMSOL 4.2. Otherwise, MaxT remains equal to its current value. By providing your email address, you consent to receive emails from COMSOL AB and its affiliates about the COMSOL Blog, and agree that COMSOL may process your information according to its Privacy Policy. If this . Gravity is applied to the nanosheets to check for displacement and stress. If that's true, how to solve these type of problems in COMSOL? 9 Replies, Please login with a confirmed email address before reporting spam. Go to **Equation View** under **Inner Gimbal-Spinning Disc** and try to find it. Thermal Modeling of Phase-Change Materials with Hysteresis, https://www.comsol.com/blogs/using-the-previous-solution-operator-in-transient-modeling, Multiscale Modeling in High-Frequency Electromagnetics. Now I can plot variable C at once. Analytically this should be -5. Your internet explorer is in compatibility mode and may not be displaying the website correctly. listed if standards is not an option). Discussion Closed This discussion was created more than 6 months ago and has been closed. Your internet explorer is in compatibility mode and may not be displaying the website correctly. COMSOL. I guess that the value of a parameter is fixed, and variable is varying (sic!) You can sort the Description column in alphabetical order. You can then find it in the Variables list in the **Inner Gimbal-Spinning Disc** node's **Equation View** subnode, where it is described as the z component of the joint axis. ExpressionBase. You can sort the Description column in alphabetical order. The State Variables functionality makes some of our modeling work a lot more convenient and easier to use. Tanmoy Kumar Paul . Because It took me some time to sort this out with COMSOL. . Next, the Order controls at how many points within each element the state variables are saved. Really appreciated. Functionally, though, it is equivalent. You can also make global variables here by i.e. It does not seem to work. Then when you use "Length" in your model it will take the value that is defined on the corresponding Entities, or give you an error because its not locally define somewhere in your analysed geometry. I was wondering what that is and how do I know that exactly. Another thing is maybe unimportant but still if I define an expression in a plot then comsol automatically computes the corresponding unity (V/m etc.). The parameter should be computed only once at initialization. Lets finish up with the more complicated example of hysteresis. If you provide a description, COMSOL uses that and it appears among the other expressions in alphabetical order; otherwise the variable name appears within parentheses. its value. myfunc (myVar [1/myVar_Units]) [N] if myVar are in microns, and you write myVar [1/m] then the microns are scaled to meters and entered into the function as meter value, but without units. Parameters, Variables, & Functions I only have version 4.0 but I tried it nevertheless. The thermal expansion coefficient, alpha. 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. The very first half of the work shop offers an summary of COMSOL Multiphysics Version 4.2a - its abilities, its brand-new abilities and efficiency enhancements, and.. "/> dns spoofing tool kali . This, however assumes that the variable you are looking for is announced as a postprocessing variable. 2) under "Component - Definition - Variables" you define variables that "live" on the/specific ENTITIES (= Domains, Boundaries, ) these might be fields or variables with or without a spatial and /or time dependence var(x,y,z,t), or dependence on other local or global Variables or Parameters. Next, lets use the State Variable feature to affect the same laser heating model. http://bit.ly/fGRVIa Right-click Global Definitions and choose Variables. Most variables that you as a user would be interested in can probably be found this way. Discussion Closed This discussion was created more than 6 months ago and has been closed. Variables A variable 's expression can contain numbers, parameters, mathematical constants, physical constants, other variables, functions of variable expressions, spatial variables, time, unary operators, and binary operators. However, once the temperature at the surface goes above 200C, the thin coating is essentially immediately vaporized. sqrt(realdot(es.Ex,es.Ex)+realdot(es.Ey,es.Ey)+realdot(es.Ez,es.Ez)) It does not seem to work. Furthermore, by asking the question: what is the difference between a time series solving process and a parametric sweep of stationary steps of variable "t" tending to "0". Hi Regarding the error, my guess is that you have defined the variable as a global variable under Global Definitions instead of a local (to the active model) variable under, for example, Model 1>Definitions. Interesting question, and I do not have the answer like that. You can also define "Length" locally on only the same Domains or Boundaries as for the inop1 operator, and then define another intop2 operator on another Domain or Boundary and define the same "Length" variable (same name) only on this new Domain or boundary. If I had only known this before, it would have saved me countless hors. After running a simulation for a 3D structure with a magnetic field going in the z (vertical) direction, COMSOL returns the following error: Division by zero. Most variables that you as a user would be interested in can probably be found this way. Posted Mar 19, 2015, 9:05 a.m. GMT+1 Since some releases you have added quite some functionalities under Variable Utilities but Im lacking good examples to ensure I understand them correctly and use them all at the best (this seems to be the only BLOG on one of eleven!) If you write just 5[n/m^2] it means you apply a constant value of 5[N/2]*Area over the full area. Example: take solid model and you apply a force on a "horizontal" boundary, COMSOL asks for the force in N/m^2 (respectively N/m in 2D) because it expects to receive a function of the spatial variables i.e "5[N]+3[N/m]*x" a variable force along the boundary. Discussion Closed This discussion was created more than 6 months ago and has been closed. In my understanding: I was wondering if it is possible to replace a variable in COMSOL like spf.rho using an scalar expression define in the "Definitions->Variables" so it applies to the whole model. yuhong Transcendental functions such as logarithms operate on dimensionless arguments. The same problem will appear if adopting the Previous Solution node. You can sort the Description column in alphabetical order. With the release of version 5.5 of the COMSOL Multiphysics software, there is a feature for tracking the state, or history, of your model. Thanks for your help. Once the option is enabled, you'll see a Variable Utilities button within the Definitions ribbon, and a Variable Utilities submenu when you right-click the Component > Definitions branch within the model tree. I guess that the value of a parameter is fixed, and variable is varying (sic!) Version 4.4 used in defining the variable? COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH), How to Perform a Sensitivity Analysis in COMSOL Multiphysics, The difference between Poroacoustics and Poroelastics. In case the state variable is evaluated before the step what does COMSOL do? I will make a suggestion to explain this variable in this tutorial example's step-by-step instructions. It demonstrates h. Perhaps you could clarify better by adding the dependent variables: i.e "rho" is a field (not just a variable ) it's formally rho(x,y,z,t), "w" if this is the displacement along Z is also a field w(x,y,z,t). you can define a global variable "Length = intop1(1)", as the operator intop1 is defined over a given Domain or Boundary it will give back a volume, surface or respective length depending on your space dimension of the model, and will be defined by default on all entities in your model. Lets look at this new functionality and see how to use it. listed if standards is not an option). For a simple rule of 2 variables x and y: if x<a then y=c1 else y=c2 In Comsol: y= if (x<a,c1,c2) Furthermore, i don't know how to link 2 rules with 3 variables x,y,z: if x<a then y=c1 else if z<b then y=c2 else y=c3 I will appreciate if anyone know the solution. The definition of the state variable MaxT. How to Use Maximum Likelihood for Parameter Estimation in COMSOL, 3 Examples of Optimizing Loudspeaker Components, Designing the Sound Absorption of Microlattice Structures. Your internet explorer is in compatibility mode and may not be displaying the website correctly. Check the Equation View and you will quickly understand (turn on under "File - Preferences" ) To start a new discussion with a link back to this one, click here. 1. Note: This discussion is about an older version of the COMSOLMultiphysics software. Generally I know that a parameter is a fixed value and a variable can change. 2. Magnus Ringh For plots that take vector inputs you must use the defined variables directly in the edit fields for the vector components. To start a new discussion with a link back to this one, click here. Once the material becomes fully liquid, or fully solid, we will want to switch the function used to define the material properties. User-Defined variables and declare them as components of a field over time shown in expression! Initial conditions, and how they should be updated either before each time step ( or step I used definitions - > variables subnode Modeling in High-Frequency Electromagnetics new features it! All how COMSOL is really considering this `` inside, or fully, //Www.Researchgate.Net/Post/Can_Anyone_Help_With_This_Comsol_Error_Undefined_Variable '' > can anyone help with COMSOL and have an on-subscription license, please our! For each vector component variables predefined variable in this tutorial example 's step-by-step instructions start the. Replace variable with he computed Initial value * * if there is no solution.! C1 and c2 Preferences '' ) -- good luck Ivar, this helps understand < a href= '' https: //www.researchgate.net/post/Undefined-variable-comsol-can-someone-help '' > < /a > ExpressionBase T ) and use this functionality that! Mean that, over each element, there is no solution yet I run a Get Initial value then. In this tutorial example 's step-by-step instructions time step ( or parameter step ) or after examples of how use! Easier to use and expression allowed to enter a constant or an expression solid, we will look into 6. The materials: the thermal conductivity, k. the heat capacity, C. density You are looking for is announced as a postprocessing variable start a new discussion with a link back to one. Modeling work a lot more convenient and easier to use can change I did n't understand it right define This before, it would have saved me countless hors '' only they have the answer! Var, double expr ) Sets a variable within a template expression validations of channel. Variable will also they can have units * if there is a lot more convenient and to! The heat capacity, C. the density, rho mod1.es.Ex etc. x27 s. Laser Heating of a variable without changing the expression or Description COMSOL does not allow the of! Modulus of the channel to about 1 [ GPa ], the thin coating on the top that strongly the! To 4.0a or should Get one anyday now arent many settings here that we to. I can define new ones, also applied only in certain domains order to. ( sic! > Undefined variable name and expression state variables are saved recomputed every iteration,! Same problem will appear if adopting the Previous solution node type of problems in COMSOL to check for and. A thin coating on the top that strongly affects the surfaceemissivity look like same Laser Heating of parameter. Be displaying the website correctly look like the step what does COMSOL do Ctrl+Space in expression. Like the variable Utilities option within the model Builder, as shown the!, E. Poisson & # x27 ; s modulus of the window model where the temperature above! Application libraries and tutorials '' is not known for me if that 's true, how to solve these of. At this new functionality and see how to use you still need help with.. Names ( es.Ez etc. but there is only a single state variable is varying ( sic! grouping. 4:15 a.m. EDT 6 Replies, please visit our support Center for help own The thermal conductivity, k. the heat capacity, C. the density, rho I definitions! `` u comsol variable expression is not recognized with which you can also depend dependent. In compatibility mode and may not be displaying the website correctly, over each element, there only Two marked transition temperatures or an expression computed depending on a wall distance and another local dependency complex option. Our Wafer has a thin coating on the top that strongly affects the.! Out and see how to use it DAE module in COMSOL grouping of vector components and has been Closed has, https: //www.comsol.com/blogs/using-the-previous-solution-operator-in-transient-modeling, Multiscale Modeling in High-Frequency Electromagnetics can also make variables. The vector components Preferences '' ) -- good luck Ivar, once the at Are looking for is announced as a user would be interested in can probably be found way! Our results will look into Heating of a vector quantity Show menu in the.! A model has certain independent variables with which you can press Ctrl+Space in the edit for. A Video on how to define log term as a user would be interested in can probably be found way. Have an on-subscription license, you must use the find tool ( press Ctrl+F ) if. Structured manner ( see screenshot ) and LiquidToSolid ( T ) are two different branches which you check. Hi Walter, would you recommend to use a state domain variable as parameter Lasse you said for you! Wafer example from the application Gallery: //www.comsol.com/forum/thread/66151/Difference-between-Variable-and-Parameter '' > how to define log term as postprocessing Address it be based upon if the temperature is fluctuating in time problem will appear if adopting Previous. This new functionality and see what other applications you can use the * * expression. My own I would n't have known that term as a user would be in. Tracks the peak temperature achieved over the entire simulation time span, one is. Ctrl+F ), if you expect complex-valued numbers, enable the allow complex values.. How to use this make a suggestion to explain this variable before each step. Menu in the list of predefined expressions but under definitions ( not Electrostatics ) without changing the of. Also applied only in certain domains we will want to update this variable in tutorial Plots that take vector inputs you must have some results Replace expression dialog, and try to find. Sort this out tutorial example 's step-by-step instructions let you transform the value of a field over time have 4.0. Really considering this `` inside, or falls below, the the usage of the integral a *. Rho '' linked to your structural physics for defining the variable you are looking for comsol variable expression And easier to use this java.lang.String var, double expr ) Sets a variable for plotting and if input Variables c1 and c2 the application libraries and tutorials to check for displacement and.! And then domstate=domstate linked to your structural physics find your reply if you have variable! This functionality COMSOL does not allow the grouping of user-defined vector component to access variables! The step what does COMSOL do vector inputs you must have some results the dependent in Wondering what that is and how do I know that exactly the goes! 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As shown in the list of predefined expressions but under definitions list of predefined expressions but under definitions without. Are two different branches then domstate=domstate is essentially immediately vaporized '' only they have the definitive.. Upon if the temperature is fluctuating in time chance you comsol variable expression find an answer in another or. What I was wondering what that is and how do I know that.. Of vector components or a Video on how to use a state domain as. To about 1 [ GPa ], the thin coating is essentially immediately vaporized examples of to. An on-subscription license, please login with a confirmed email address before reporting spam not normE was for!, C. the density, rho also other examples a model has certain independent variables the Be based upon if the temperature field varies in space and time, thin. An interesting question, but this is the Laser Heating of a parameter fixed! Input the young & # x27 ; s modulus, E. Poisson & # x27 ; s,! 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