i need to find the velocity field of a gas flowing inside a square pipe. they say that there is a lot of bibliography about, because it is a subjet well developed. unfortunately i dont have access to sites where u have to pay for. could u suggest me some links or ideas to reach my task?

tanks a lot in advance...

Since no one else has answered your request, I will give it a try. One source of the solution is the book by Frank M. White, "Viscous Fluid Flow," second edition, page 120. White gives the solutions for many ducts of different shapes. For the rectangular duct, the solution is in the form of a series of products of hyperbolic cosines and circular cosines.

I presume one does the usual separation of variables into products of functions of y and z. This no doubt leads to separate equations for the two functions which can be reconized to have hyperbolic and circular solutions. One then applies no-slip boundary conditions which leads to the sum mentioned above.

tanks a lot for ur answer!!! i'm gonna try to find out this book...

PS it was very sad to see my message abandoned...