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Doubt about transitorial analysis
Posted 2012年11月5日 GMT-5 20:45 Fluid & Heat, Computational Fluid Dynamics (CFD) Version 4.2a 3 Replies
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I have a doubt about transitorial analysis. Let me explain: I´ve been looking for tutorials about the subject and I found one of CFD concerning a cylinder, I leave the link so you can check it:
www.comsol.com/showroom/downloadfile/model/97/version/comsol42a/file/models.mph.cylinder_flow.pdf
In this toturial a Step function is declared and is used to vary the average speed from 0 (zero) to U_mean.
My question is: Why is the funtion Step_1 used in the argument t[1/s]? According to me, we could use t[s] to obtain a "linear variation", even t would be valid as an argument to the function Step_1.
The point is, I have done this changes and the program is marking me errors.
Thanks
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the reason for the t[1/s] is to make "t" witout units as most functions expect unitless values,
"t" has by default a unit of "s" so t[s] means s^2 type units
if you wtite t[1/min] t would count in minutes, that is 1,2,3 would correspond to minutes, while t[1/h] in hours etc
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Good luck
Ivar
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Greetings from México
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Youre welcome
From Switzerland, here ;)
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Good luck
Ivar