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Solid-Body kinematics inertial coordinate system

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Old   September 22, 2014, 12:56
Default Solid-Body kinematics inertial coordinate system
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Francisco
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Hi everybody,

I'm trying to define a solid-body 3D motion for a body. This movement is defined by a rotation along y-axis and a rotation along z-axis from a center of rotation.
I've made a profile file in transient table format with three columns: time, theta_y and theta_z (I attach the profile in txt). I choose the center of rotation as the center of gravity.
Fluent is suppose to work with inertia coordinate system, which is what I want, but I think the z-axis is not being rotated when the theta_y angle is applied. Z-axis remains fix as in an absolute coordinate frame.
I've read in the Fluent 12 User's Guide you are supposed to change the inertial/absolute coordinate system in the Fluid dialog box, but I don't find where. Probably because I'm using v14. Here it is:

"By default ANSYS FLUENT assumes that the motion is specified in the inertial coordinate system. However, it is also possible to prescribe the motion relative to the coordinate system by selecting the Motion Type from the drop-down list for the respective fluid zone defined in Fluid dialog box. Thus the motion may be prescribed relative to a Rotating Reference Frame, Moving Mesh, or as Stationary."

In Fluent 14 User's Guide it just says inertial system is chosen.

What am I doing wrong?
What can I do to choose the inertia coordinate system?

Any help would be highly appreaciated! Thanks a lot!
Attached Files
File Type: txt trayectoria_3D.txt (3.5 KB, 7 views)
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Old   September 23, 2014, 05:46
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Francisco
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I've tried a different 3D path, consisting in a x-axis displacement and a z-axis rotation. Z-axis is not being rotated just displaced. In this case it works fine, so I guess the issue comes when the movement involves rotating axes as in the previous example (z-axis rotating around y-axis). I think the profile uses an inertia coordinate system only inertial for the displacement and not for the rotations.

Anyone has experienced anything similar?

Thanks!
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inertia coordinate system, profile files, solid-body kinematics

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