February 19th, 2019, 02:16 AM  #1 
Member Joined: Feb 2018 From: England Posts: 61 Thanks: 0  Speed of rotation.
Hi All, How can I find of the speed of rotation without rpm or any speed? A bearing on a flywheel has a diameter of 28.0mm and axial length 18.0mm with a radial clearance of 14.4 micro m. The kinematic viscosity of the lubricating oil is 2.09 x 10^5 m^2 S^1 and the density is 835kg m^3. If the power loss of the bearing is 1.34KW, how is it possible to calculate the rotation? I am unable to calculate the angular velocity and rotation rate without ω? ω = 2 πn/60 I have also tried using Petrov's equation Power loss  2 πR³lw²/Cr. Any guidance would be appreciated. Last edited by skipjack; February 19th, 2019 at 05:17 PM. 
February 19th, 2019, 05:41 AM  #2 
Senior Member Joined: Apr 2014 From: Glasgow Posts: 2,150 Thanks: 730 Math Focus: Physics, mathematical modelling, numerical and computational solutions 
I think Petroff's equation is the one to use here. Can you rearrange it to make the angular velocity the subject?

February 19th, 2019, 12:20 PM  #3 
Member Joined: Feb 2018 From: England Posts: 61 Thanks: 0 
Hi Benit13, I was thinking the same but doubting myself its the wrong approach. I will try rearranging the equation, not an easy one is it. Many thanks. 

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