Siphon model/ Water air interaction
Hello, At the moment I am trying to model a simple siphon situation. I attached a paint picture of what I want to model. Unfortunately I am not able to tell Comsol that there is movement of the water...
View ArticleProblems Using Particle Tracing for Fluid with Time Dependent Laminar Flow
Hello, I am trying to run a 2D simulation where the Particle Tracing Fluid physics is being run alongside the laminar flow physics as they are both time dependent. However when I run them I keep...
View ArticleVibrating Pipe
Hi, all I am a Comsol novice user. I am going to simulate the vibrating pipe with the viscous liquid inside, but I have no idea How to set the wall pipe to vibrate. In detail, I would like to vibrate...
View ArticleApplying vibrations/sudden force on a liquid in a container
Hi everyone, I am trying to apply a vibration/sudden force to a liquid in a container. This liquid has a yield stress of about 0.6 Pa. I would like to know what vibrations/force can bring this liquid...
View ArticleContradiction in COMSOL's Documents
Hi All, I have found a contradiction in COMSOL's manual about the same example that has different names in version 3.5 and 4.4. In 3.5 the PDF document states that Reynolds number = diameter of the...
View ArticleReynolds Number in Micro Diffusers-Nozzle
Hi All, What is the suitable formula to be used to calculate Reynolds number in a micro diffuser-nozzle structure, as the picture attached? I am using: Reynolds number = hydraulic...
View ArticleProblems with static mixer simulation (diffusion vs convective mixing)
I am trying to simulate a static mixer to assess its mixing quality through multiple iterations. It is meant for liquids with minimal diffusion such as latex paint in the realm of 750 Pa*s viscosity. I...
View Articlesedimentation tank with mixture model, laminar flow
hello my name is Andrew and I am Colombian. The reason I write to you is because I am in a research project on optimization in the design of sedimentation tanks, then I'm applying computational fluid...
View ArticleCoupling Darcy's law with Navier-Stokes equation - convergence problem
Dear Comsol-Community, in the hope that someone of this great community might help me, I will try to explain my current problems with coupling Darcy's law and laminar flow. Basically I want to study...
View Articlemultiphysics couplings
Hi everyone, I have a question about multiphysics couplings. Now I am doing a water cooling project and I need 2 physics fields: (1)heat transfer in both solids and fluid;(2) laminar flow . After...
View ArticleChoice between 2D and 3D simulation
I have added an image,it is MEMS based microresistojet thruster. I need to simulate it using CFD.The middle portion is a heater wall,which will be used to heat Fluid.Can somebody tell me should i model...
View ArticleThermocapillary recirculation
EDITED Hello, I am a beginning user of COMSOL. Currently, I am trying to create a preliminary model of Marangoni convection, like this one available on the COMSOL site:...
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Inlet boundary condition - coupling local inlet velocity with local static...
Dear Comsol Community, as already described in the linked discussion (www.comsol.com/community/forums/general/thread/54351/) I want to study the steady flow in the gap between an air-hockey table and a...
View ArticleNeed help with Mixture Model
I am trying to simulate a baffled separator using mixture model for separating liquid from gas, however I am getting these problems. How do I define both the gas and liquid in the domain ? When I...
View ArticleHow to create Loops for fluid flow
Dear Forum members, Is anyone knows how to create a loop in comsol multiphysics, so that the flow passages are repeated with some increments? I have a solid bed at high temperature trnasferring his...
View Articlematlab/comsol unit problem
My problem is Diffusion eq + Navier–Stokes eq I am solving diffusion equation which has unit (mm) in Matlab and Navier–Stokes eq in Comsol (SI unit). I could not decide how to get out of unit problem....
View ArticleBody force driven flow
Hello all, I am trying to generate a body force driven flow. Consider a simple pipe , radius 0.2 m , length 2 m. Lets assume there is a uniform volumetric body force of ( the momentum source term F)...
View ArticleOutflow of a channel
Hi, I am facing a problem of outlet B.C. in a 2D open channel problem with turbulent flow. In physics, the outlet velocity and pressure should be unknown and controlled by a gradient condition du/dx=0...
View ArticleUser defined non-Newtonian models
Hi there, I am trying to implement a non-Newtonian constitutive relation which is different than Carreau and power law in the CFD module. My viscosity model is a function of both shear rate (gamma dot)...
View ArticleFlow inside the tube with rotary-piston
hello everyone I am a beginner in COMSOL and please if someone can help me. I am constructed the tube fi 140 mm (inside diametar) lenght 1m. Outside diametar of the tube is fi 150mm. Mateial of the...
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