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Old   August 8, 2012, 21:52
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Dear All,

Anybody know how to find the rpm (rotation per minute) if i use propeller GMO object which due to fluid flow?

Thank you in advance..
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Old   August 13, 2012, 18:15
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Look in Analyze->probe->general history->"GMO ... axis angular velocity". The output is in rad/sec.
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Old   August 14, 2012, 01:35
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Thank you very much..
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Old   August 14, 2012, 05:57
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Quote:
Originally Posted by dmilano View Post
Look in Analyze->probe->general history->"GMO ... axis angular velocity". The output is in rad/sec.
Dear friend
is this in ansys or star-ccm+,cuz my problem is in star-ccm...
thanx for u help
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Old   August 17, 2012, 02:20
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Quote:
Originally Posted by dmilano View Post
Look in Analyze->probe->general history->"GMO ... axis angular velocity". The output is in rad/sec.
How I can find the torque of the GMO? There is in the probe 3 types of torque:
"fluid i-torque about fixed axis"; "fluid torque magnitude about fixed axis" (that is the absolute value of "fluid 1-torque about fixed axis"); "residual i-torque about fixed axis".
Which one is the correct one?
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Old   August 17, 2012, 10:47
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Component ... GMO fluid x-torque about fixed point: the x component of the fluid torque about the specified rotation point
Component ... GMO fluid torque magnitude about fixed point: the total fluid torque about the specified rotation point (the vector sum of the x, y, and z torques)
Component ... GMO residual x-torque about fixed point: the torque about the specified rotation point that is used to overcome the torque contributions of the inertial forces, body forces, viscous and pressure forces, and specified control forces (or torques) in the x-direction.
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Old   August 17, 2012, 11:31
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Quote:
Originally Posted by dmilano View Post
Component ... GMO fluid x-torque about fixed point: the x component of the fluid torque about the specified rotation point
Component ... GMO fluid torque magnitude about fixed point: the total fluid torque about the specified rotation point (the vector sum of the x, y, and z torques)
Component ... GMO residual x-torque about fixed point: the torque about the specified rotation point that is used to overcome the torque contributions of the inertial forces, body forces, viscous and pressure forces, and specified control forces (or torques) in the x-direction.
Thanks!
obviously I can change "about fixed point" with "about fixed axis", in fact becouse I have to simulate a turbine that rotates around a fixed axis. Correct?
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Old   August 17, 2012, 12:14
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yep - you are correct
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Old   August 24, 2012, 10:02
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I need help!!
In my simulation of a turbine i use gmo couplet motion with fixed axis.
The turbine is made of ABS so the density is very similar to the water.
In the GMO option what method I must use? Implict or esplicit?
Which one is faster for the simulation?

Thanks.
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Old   August 24, 2012, 10:12
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Use the implicit option in this case
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Old   August 24, 2012, 10:16
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Quote:
Originally Posted by dmilano View Post
Use the implicit option in this case
Thanks!
There is a reason to choose the implicit method, or of experience is the faster?
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Old   August 24, 2012, 11:23
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I find that it usually just works better
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Old   August 25, 2012, 03:45
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ok.
Another question.
In probe output there is the "residual x-torque about fixed axis".
I'm running a coupled simulation with a total torque control in the "moving object setup" tab.
But the "residual x-torque about fixed axis" has always the value of zero.
The only way to obtain a value for "residual x-torque about fixed axis" is to use a prescribed motion with a angular velocity impose to the turbine.

It is correct or I have done something wrong?

In the manual I found that : "Residual control force and torque in both space and body systems for any prescribed motion and a coupled motion with constraints (fixed axis, fixed point and prescribed velocity components)"
It means that if i impose a coupled motion with total torque control, the residual output doesn't appear?

Thanks!
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Old   August 27, 2012, 13:38
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The residual torque/force is only non-zero in the directions with prescribed or zero velocity components. For example, it may be non-zero in the direction perpendicular to the rotation axis.
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