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Confused with rpm setting in the Single Fluid Rotating Machinery (constant velocity)

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Hi,

The question arises from the model "baffled_mixer" in the Model Gallery. (Rotating Machinery, Laminar Flow)
The impeller is rotating at 10rpm (constant velocity).
But when they set the rpm under Variables, this is what it appears like:

Name: rpm
Expression: 10[1/min]*step1(t[1/s])
Description: Revolutions per second


Could someone explain what "step1(t[1/s])" portion is means?
If I change the step time (from 0.25s to 0.5s), would it change the 10rpm to a different value then?

Does 10[1/min]*step1(t[1/s])
represent constant velocity with no acceleration?


1 Reply Last Post 21 juil. 2011, 06:18 UTC−4

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Posted: 1 decade ago 21 juil. 2011, 06:18 UTC−4
Hi JC

In this case step1 was ramp function from 0 to 1 at certain time period. Function can be found somewhere but I don't remember where (I don't have Comsol available now, so I can't check).

Best regards

Tero
Hi JC In this case step1 was ramp function from 0 to 1 at certain time period. Function can be found somewhere but I don't remember where (I don't have Comsol available now, so I can't check). Best regards Tero

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