I want a cube with a circular inlet on its top face!

I tried it in Gambit by making a cube(volume) and then subtract a circle from top face but it doesn't allow and says "cannot subtract a face from upper topology"

Also, i tried by starting from vertices and made 6 faces of cube then subtracting circle from top face but then when i ask it to convert it into volume it gives an error "Is this an open shell"

my guess is that it considers it a solid volume and making a circular inlet in top face does not make sense but then how do tell gambit that i have air in this volume??

.....What is the way to get around with this??

a number of ways, here is one of them: 1) make 6 square faces 2) make a circular face (not edge) 3) split the square face with the circular one 4) get all the edges connected (just in case) 5) now make a volume by stiching all the faces

better thing to do for meshing nicely would be splitting the cube with the cylinder, but it depends on the problem.

hi meenu.

you can t subtract.. the faces from volumes.. all you have to do is to split the faces.. option. and if you want an inlet or outlet no need to subtract the faces,.. you define the face as inlet/ outlet in the B.C panel.