Does anyone has created an *.xls file to extimate the size of the boundary cells that should be used when creating the grid in Gambit? Like that you can set all the parameters like bulk velocity, temperature, material,...and the electronic sheet suggests the value of y to be used in order to obtain the right values of y+ for the turbulence model and wall treatment that will be used in Fluent. If no one has already done it and would like to help me to create it, well, let me know!!

Thomas

I hope that this could help you: http://www.cfd-online.com/Wiki/Dimen...wall_distance_%28y_plus%29 I use the first calculator that is listed in that page and works for me. Take care.

Thank u very much for the link: I've created my xls file utilizing the formula derived from the HTML of http://www.simuserve.com/cfd-shop/GOODIES/YPLUS.HTM for the wall shear stress: Cf = 0.455/(ln(0.06*Re))^2 tau = 0.5*rho*V^2*Cf u* = (tau/rho)^(1/2) My excel file works for every fluid starting just from composition, velocity and characteristic length and imposing the required y+ value; I've tested it with some cases I've already studied with Fluent: there's a very good agreement. Do you have any idea on how the formula for tau has been derived? Thank u,

Thomas