Thanks, Maimouna!
Look forward to your reply! Best regards Jason Quote:
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1. Follow your method below, I can only get the x of the mass center. Do you know how to get all x y z? 1. As posted, I'm still not sure if there is a way to get all components. Might there is some expertises could help me, you and others. 2. Try one by the time, I mean try to change mass first, if doesn't work change stiffness and then damping or what ever you would like to begin with. Honestly, I don't have time to test that with you, so try them and let me know if that work or not. Just in case getting time in the next few days, send me your case study problem (domain, BCs, Re, all possible information) to have a look. All the best Maimouna |
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1. Follow your method below, I can only get the x of the mass center. Do you know how to get all x y z? Code:
set title "Centre of Mass" Kind regards Maimouna |
Thanks, Maimouna! That's a great help!
Regards Jason Quote:
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oscillating cylinder dynamic mesh
Have someone tried 2nd order temporal accuracy in the vortex induced vibration cases? The wingMotion tutorial used Euler, which is a first order ddtScheme. In my VIV around a circular cylinder case, when I change it to a 2nd order accurate backward, the computation diverged!
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Short answer: yes
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no damping effects in free decay test
Hi everybody!
I'm simulating free decay tests of a vertical floating cylinder in OF 2.3.0, with interDyMFoam. The cylinder is moored to the bottom with four linear springs. it works, but it seems to be not realistic, because the motion is almost not dampened. Did anybody work on this topic? can you suggest me the reason or the way to solve the problem? Thank you very very much in advance. Agnese |
Hi, Jan!
Did you manage to solve this problem of divergence with second order temporal scheme? Quote:
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Can you upload your case file so that we can have a discuss? |
where is the aerodynamics coefficients implemented?
Hi everyone!! I am new in this forum, because I am trying to learn OpenFoam, and I find this information very useful to my case, so thank you to all.
Well, I am reading and practice this example using gmsh to mesh and trying to get something good, but i have a question, Where is implemented all the aerodynamics coefficients? Because I have seen how this example give me some drag coefficients and lift coefficients , but i don't know how I can use to another case. So where is the lift, in the fvSolution and fvSchemes? Thank you in advance for any help you can give! Xjokjok |
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xjokjok |
Hi
Lift and drag coefficients should be output from the calculation of OpenFOAM, not the input. For input, such as stiffness, damping, they are defined in dynamicMeshDict file in constant folder. Quote:
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I too am in need of a validation case to validate my model in openfoam. Did you have any luck with it? Can you help me out too? |
Doubts about report 6-DoF
1 Attachment(s)
Hi everyone,
I've been working with free cylinder in an oscillating flow. I'm using 6-DoF rigid body motion with transverse direction of flow (y) allow to move. No matter what I do, the log file not contains information about 6-DoF such as centre of mass that I need to capture the movement. I put on the report and the reportToFile too but nothing. I using openFOAM 2.4, ubuntu 14.04 LTS. Then I installed openFOAM 3.0 to try to overcome the error. But nothing change :( I will be very grateful with your help. Best regards dynamicMeshDict file: Code:
dynamicFvMesh dynamicMotionSolverFvMesh; Code:
dimensions [0 1 0 0 0 0 0]; Attachment 50314 |
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Hello Behzad
Many thanks to replay. You can find 2 attachments bellow, with openFOAM 2.4: https://drive.google.com/folderview?...ms&usp=sharing 1. oscillating_1000_1: the dynamicMeshDict file has a sixDoFRigidBodyMotion as the solver and the sixDoFRigidBodyMotionCoeffs are presented here. 2. oscillating_1000_2: the pointdisplacement file has the sixDoFRigidBodyMotionCoeffs and dynamicMeshDict has a displacementLaplacian as the solver. I tried to use both ways that I found in some forums and I changed thinks like mass, stiffness and restLength but the movement of the cylinder is not displayed and there isn't 6-DoF data information in log file. I'll be waiting for any idea to solve my problem Thanks... |
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https://drive.google.com/file/d/0B5M...ew?usp=sharing |
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Similar to the discussions in this thread, I am simulating the cube shaped object vibrating along only one axis (oscillating)in water. I used linearSpring. I can successfully make it vibrate (free vibrations without damping) at its natural frequency (calculated from stiffness and mass), and validated with the analytical calculations. Now I want to add an external force so that the object will vibrate at various frequencies other than its natural frequency. One attempt: I tried to modify restraintforce equation in the linearSpring.C file, by adding the external force term F0*sin(wt), but it didn't work may be because I couldn't add "time, t" in there. What do you suggest to solve this problem? Many thanks in advance. Best regards, Sachin |
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Thank you very much for your help. I saw your changes, comments and log file. Everything seems to be good. So I proved the model that you send me and the log file doesn't show any information about 6-DoF or mass center. Maybe there is a problem with the OF instalation or some libraries are missing, I don't know :( For installing OF I used this link https://openfoamwiki.net/index.php/I...M-2.4.0/Ubuntu for Ubuntu 14.04 and install from source For running I generat the mesh with "blockMesh" and then I enter the command line "pimpleFoam" I'll be waiting for a comment Thanks again |
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