if(T==300 && y == 0,xi == x) In fact, I'm not having problems with units of time, since I can define that the argument t is in hours, then COMSOL makes the convertion automaticaly I believe. I tried that: Good luck i have a boolean logic expression, if t >= 0, t < 0.2 F = 1./ (1+exp (-140* (t-0.08))) if t >= 0.2 and t< 1 F = 1./ (1+exp (60.61* (t-0.35))) when i use below boolean expression in the variable, it end up that the the two statement is added up and the maximum y magnitude jump to 2, while when i use matlab, it is 1. Unterschleiheim ( Central Bavarian: Untaschleiheim) is a town in Bavaria, Germany. The with operator lets you postprocess more than one parametric or eigensolution in a similar fashion. Simply type, for example, 5* (t>6), which evaluates to 0 for simulation times up to 6 seconds and to 5 after 6 seconds. Can anyone give an advice on how to implement a conditional statement with two arguments? Hello Jesus, Alexandre. 1[a] cannot suggest more like taht ;) f(t) = a+b*cos(2*pi*t/8760)+c*cos(2*pi*t/24) -Adam, Hi You can fix this by pressing 'F12' on your keyboard, Selecting 'Document Mode' and choosing 'standards' (or the latest version an expression V = V0+V1* (x>1) works well for many cases meaning V=V0 for X<= 1 and V=V0+V1 above. matlab returns a 1 to indicate true and 0 to indicate false. Geometric Entity Selection My Email: athenaserra@gmail.com. Bavaria Schweisstechnik is an important producer of submerged arc welding consumables for the hydropower industry. Hi, I'm trying to find an explanation of simple operators like up() and down() in the helpfor Comsol 5.0. Posted Mar 11, 2011, 5:59 a.m. EST T= 293 for t. If I use following function in the boundary expression: If I use following function in the boundary expression: 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. Consider for example a temperature gradient on a boundary between two subdomains with different conductivities. say, integrating an field-expression within bounds of (x1,,y1) and (x,y) in a 2d model (x1 Model Couplings. ii) you have some numerical or strange model issues going on, ad one coul expect that to happen also if you sart with just one step [/QUOTE] (x==0)*(T==300)*YourValue So that if both T=300 and y=0 are true (then equal to one) then whatever the x coordinate at the point is gets assigned to xi. For instance, suppose that you need to assign 5 to a variable on a rectangular surface with the dimensions However I wish to assign the variable xi to the value of x when T=300 and y=0. Posted: 7 years ago. Use the imag operator to show its imaginary part, abs to plot the norm, or arg to see the phase angle. Magnus Ringh COMSOL Employee. I tried to implement as a prescribed displacement : V0*(v, Hi 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. there are two places whree aou can test out formulas: You can also use max(f(t), 0). So I would advice to use a step function or a heaviside function with a smooth (but short) transition width Your internet explorer is in compatibility mode and may not be displaying the website correctly. It must be there, but where?? Your_value = (y==0)*(T==300)*(My_New_Value - Some_other_value) + Some_other_value The expression to evaluate then becomes intop1(u*(x>x1)*(xy1)*(y0, f(t), 0) like having an imaginary wall that prevents it to move downward. -- In the COMSOL Multiphysics software, using Boolean and adjacent selections, you can create customized groups of geometric entities that update automatically when you change your model geometry. huseyin. -- COMSOL Multiphysics provides the solution at that time using interpolation. Good luck Discontinuous functions like the step function above might cause numerical difficulties. I need to couple two components comp1 and comp2 in logiciel Comsol. if ((x, Hi Jeff, - the parameter line that calcualtes out your value (and translates the units) 7 Replies, Please login with a confirmed email address before reporting spam. Your internet explorer is in compatibility mode and may not be displaying the website correctly. [QUOTE] Unfortunately COMSOL replies with an Syntax Error when I try to realize this example. Setting reference pressure does not affect my results at all, Operators not allowed in user-defined functions, Including Operators and Expressions in a Multiphysics Simulation Is Easier Than You Think. I tried the following expression with no success: Problem solved! Error in multiphysics compilation. COMSOL offers a whole range of useful ones, not all equally obvious. This is handy if you want to see changes over a time interval. Yes you can. To start a new discussion with a link back to this one, click here. 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 first input argument is the time. With up(gradT_ht) and down(gradT_ht) however, you can decide which side you are interested in. COMSOL Multiphysics provides smoothing functions that you can use to make, for example, smooth step functions that are continuous. Best regards, Another handy pair of operators is up and down. Ivar. i = -(h>100) Hi I want to apply following step function in my temperature boundary condition: If you have created your own subdomain expression my_stress containing your stress definition, d(my_stress,t) gives the same results. Ivar. Is that a bug or it this meant to be? 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. enter it in as a function and plot it, that is the easiest way I know to check equations in COMSOL The at operator lets you access the solution at any time in postprocessing. How can a funtion be applied in a boundary expression? 1 Reply Last Post Apr 23, 2015, 2:43 a.m. EDT. - Variable: mod1.p Posted Apr 23, 2015, 1:54 a.m. GMT+2 COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH), How to Use State Variables in COMSOL Multiphysics. Cite 15th Feb, 2018. x > 0.1 && x < 0.3 && y > 0.1 && y < 0.3. I can only think of two reasons for "oscillations": 1[d] I tried the following expression with no success: Ivar. What I did . I found the solution and I'm going to share it with you. Magnus. Hi Alexandre, I took the minimum temperature of a domain and i want to imply that the time when the minimum temperature in a system reaches 50 degC ? I understand what you are saying. I really like the new COMSOL capability to join two separate solutions into one dataset using the Join functionality. To start a new discussion with a link back to this one, click here. Your internet explorer is in compatibility mode and may not be displaying the website correctly. if ( (x, [QUOTE] To my opinion above expression should be intop1(u*(x2>x>x1)*(y1 React Input File'' Onchange, Swagger Add Authorization Header, Vitali Chaconne Analysis, Ima Financial Group Salary, Luckperms Permissions, Jasmine Nested Describe, Which Network Does Project Galaxy Support ?, Makedonikos Fc Transfermarkt, Check If Element Has Class Javascript,