Physics Help Forum reynold number formula

 Feb 27th 2016, 07:38 AM #1 Senior Member   Join Date: Jun 2014 Posts: 306 reynold number formula can someone explain why the force of inertia is ρ(V^2)(L^2) , while the viscous force is μVL ? Attached Thumbnails
 Mar 1st 2016, 06:16 AM #2 Junior Member   Join Date: Feb 2016 Posts: 16 Reynolds number is a dimensionless number used to define the type of the fluid flow. we have a lot of other dimensionless numbers, such as Rayleigh, Mach, Prandtl etc.. each help us to define the governing physical phenomena dominating a certain problem, inertial vs viscous forces in case of reynolds number. Example: let say you want to design a new ship prow. instead of building a full size one and test it you can build a much smaller one, test it in your lab and by comparing or adjusting Reynolds numbers (and other non-dimensional numbers) you can predict the behavior of a full size prow (e.g.drag forces) you can read about "Buckingham π theorem" for deeper understanding
 Mar 1st 2016, 12:43 PM #3 Senior Member     Join Date: Apr 2008 Location: Bedford, England Posts: 668 Look at the dimensions of ρ and μ. __________________ You have GOT to Laugh !
 Aug 7th 2017, 05:42 AM #4 Junior Member   Join Date: Aug 2017 Posts: 1 nice

 Tags formula, number, reynold