Poisson-continuity coupled equation
Hello, I try to model the corona discharge in wire-cylinder geometry governed by the equations: nabla (V) =- rho/epsilon0 (Poisson equation) and grad (rho) * grad (V) = rho ^ 2/epsilon0 (equation of...
View ArticleAsynchronous Machine time dependent startup, singularity error
Hello, I am trying to simulate a ASM in the rotating machines physics, time dependent. The Stator slots are coupled to the electrical circuit physics for a Voltage excitation The rotor slots are also...
View ArticleGeometric Nonlinearity problem
I have an odd problem. I am trying to recreate the Large Deformation Beam model (www.comsol.com/showroom/documentation/model/204/) before I start my own project to investigate buckling. I was following...
View ArticlePML for SAW interdigital transducer
Hi, i'm trying to simulate an interdigital transducer for SAW on a lithium niobate substrate but i have a lot of problems adding PML. I have previously simulated using periodic conditions but now i'm...
View ArticleStop condition in Electromechanics(emi)
I would like to implement a stop condition similar to what is described for a moving mesh problem. The parametric study would stop when the mesh quality is lower than a certain value, inorder to...
View ArticleCoupling between PDE and Electrostatics
Dear All, Does any one have any experience of solving a steady general form of PDE with steady electrostaics module. I am trying to solve a PDE [ Div(DuE) = 0] where D is the mobility coefficient and E...
View ArticleError: 7161 The mass matrix is zero - resolve
Respected sir/ma'am, I am trying to simulate a Nano ElectroMechanical Switch(NEMS) using the following modules:a)solid, stress-strain, b) Moving Mesh, and c)Electrostatics. When i run the solver, it...
View ArticleThermal Stress Evaluation without Solving Heat Transfer Physics
I am trying to generate Thermal Stress about the domain of a spherical body with a coupled 'Solid Mechanics' and 'Heat Transfer in Solids' physics. Instead of actually solving the heat transfer...
View Articlethe free vibration of the cantilever
Hi everyone: The initial displacement D=1.05mm, is placed on the end of the cantilever beam, to solve the velocity response of the beam end. First, I select space dimension 2D, and add physics Beam,...
View ArticleIssues with Full Coupling of Physics
Good day, I am having issues with fully coupling two physics. My system contains the solid mechanics physics coupled with a general form PDE to model concentration change and the diffusive properties...
View ArticleExtrap
Hello Comsol gurus, I am doing a CFD simulation in which I need to use the solution of another CFD simulation. I need to take a "slice" of the solution and use it in another geometry. As I understand,...
View Articleaccess to any solution (more than one parameter)
Hello When I do a parametric sweep with only one parameter, I can access to one particular solution with the operator "with", for example, with(1,emw.Ez) gives me the z-electric field for the first...
View ArticleParallel plate model with magnetorheological fluid under magnetic field
Hi, I am trying to model the flow fields of magnetorheological fluid between non-magnetic parallel plate and permanent magnets under magnetic field produced by permanent magnets in in COMSOL3.5a. There...
View ArticleList expressions and predefined quantities in Maltab or Java
Hello everyone, I'm looking for a way to find the "expressions and predefined quantities" a model offers within matlab or java. Via COMSOL-GUI, this is simply possible by clicking one of the two...
View Articleparametric sweep in a contact problem
The attached file shows a simple axisymmetric problem in 4.3a where a screw-shaped part is being pushed into some uniform bone by an axial force. In the attached model, there are identity pairs between...
View ArticleHeat transfer from the pipe to surroundings
Sir, We found three options for "Wall Heat transfer" in "Non-Isothermal Pipe Flow" namely 1. Temperature (nitf/nitf) 2. Temperature (nipfl/nipfl) 3. Userdefined. (with an option to check "Take average...
View ArticleMeasuring the temperature at a point
Sir, In a non-isothermal pipe flow model, we have specified wall heat transfer with external temperature as 293.15K and the check box for taking average from adjacent domains is also checked. After...
View Articleout of memory during LU factorization ?
I use comsol multiphysics 4.2 to solve a model on my computer(with 2GB RAM), I get the error "out of memory during LU factorization", but when I put the same model into another computer(the same cpu,...
View ArticleFrom PDE to linear algebraic equations. Algorithm of solver
Dear Sirs, please advise me with my deal. I simulated a model in ACDC->Electric currents. As I can see there are some differential equations which FEM approximates into a system of nonlinear or...
View ArticleConstrains and laminates
Hello, id like to simulate a laminate with around 5 isotropic laminated layers. These layers are in the form of a plate with a constant area load. The model is a laminate for photovoltaics with area...
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