Hi,

i calculated the Reynoldsnumber where i need the revolutions per minute. What struck me was the conversion from rpm to 1/s -> 60rpm = 1 rps = 1 s^-1. According to smath 60rpm = 6,28 s^-1.

Is there a bug or are i'm doing the math wrong?



thanks a lot!

please read here (SS-2395) (you can vote and comment it), here or here (and other...)

base unit of a revolution is coded as 2pi radians (not 1), hence the multiplication factor.

This is because the standard unit in SMath for rotation is radian = 2*pi which is ~6.28. If you look at the definition of rpm it is pi/30 1/s or 2*pi/60.



In order to get the right result you need to divide by 2*pi. What i would suggest is creating your own unit for RPMs as done in the attached.

rpm.sm (2 KiB) downloaded 73 time(s).



Edit: Davide beat me to it.

Wrote

This is because the standard unit in SMath for rotation is radian = 2*π

... and this is because trig functions are numerically approximated in radian.
Those functions are native in Microsoft, used by math software as is.

thanks a lot for your quick reply, good to know