Laplace number represents the ratio of surface tension to momentum- transport inside a fluid. it is used in the characterization of free surface fluid dynamics. show that the laplace number is dimensionless. the laplace number is expressed as: = / where σ = surface tension, rho = density , l = length and μ = liquid viscosity. the units of liquid viscosity are kg/(m. s) and for surface tension are n/m

Ajournal bearing has a journal diameter of 3.250 in with a unilateral tolerance of 20.003 in. the bushing bore has a diameter of 3.256 in and a unilateral tolerance of 0.004 in. the bushing is 2.8 in long and supports a 700-lbf load. the journal speed is 900 rev/min. find the minimum oil film thickness and the maximum film pressure for both sae 20 and sae 20w-30 lubricants, for the tightest assembly if the operating film temperature is 160°f. a computer code is appropriate for solving this problem.