# Moment Center and Moment Axis as a function on flow-time

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 February 1, 2019, 08:14 Moment Center and Moment Axis as a function on flow-time #1 New Member   Federico Join Date: Sep 2017 Posts: 13 Rep Power: 8 Dear all, I am currently working on a sliding mesh set-up involving the simulation of the flow passing through a tidal turbine. One thing I am struggling with is how to monitor the moment of a force in such a problem: At each time step (if I refer to a blade) I have that Moment center coordinates and moment axis components are changing. I tackled this aspect by typing on execute command text line the following: (define t (rpgetvar 'flow-time)) (define omega 7.644542) solve/monitors/force/set-moment-monitor cm-x y 28 33 , y y /Path/to/cx1.txt n n (* 0.036 (sin (* omega t))) (* 0.036 (cos (* omega t))) 0 (- 0 cos (* omega t)) (sin (* omega t)) 0 The following warning and errors appears although a cx1.txt file is outputted: (define t (rpgetvar 'flow-time)) t (define omega 7.644542) omega Error: + (add): invalid argument [1]: wrong type [not a number] Error Object: #[primitive-procedure cos] solve/monitors/force/set-moment-monitor cm-x y 28 33 , y y /Path/to/cx1.txt n n (* 0.036 (sin (* omega t))) (* 0.036 (cos (* omega t))) 0 (- 0 cos (* omega t))Invalid real. (sin (* omega t)) 0 z-component of moment axis [0] Anybody knows what this Errors mean? I would like to stress the fact that a file ( cx1.txt) was written! Do you think the aforementioned mathematical expression was calculated? Hope you can help me with this!! Thank you in advance Best regards, eeLio

February 1, 2019, 10:40
#2
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Lucky
Join Date: Apr 2011
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Quote:
 Originally Posted by eeLio solve/monitors/force/set-moment-monitor cm-x y 28 33 , y y /Path/to/cx1.txt

I think the issue is this comma , appearing here but I can't really tell because I don't know your entire case setup. Just go into Fluent and manually type in solve/monitors/force/set-moment-monitor and then follow the prompts.

 Tags execute command, force monitor, sliding mesh, turbine