Help me draw corrugation in the inner wall of a cylinder using HFSS

I'm doing a simulation of the interaction between RF waves and the particles in the high power amplification devices (such as Magnetron). The Magnetron is constructed of two concentric cylinders with the output cylinder has corrugations in its inner wall ( these corrugations some times is called Vanes).
Now, the questions are:
1
-How can i draw these corrugations in the inner wall of a 3D cylinder ? i could draw a two concentric cylinders but i couldn't make corrugations in the inner wall of the outer cylinder. These corrugations are actually made by putting thin metal plates has the same height of the cylinder and distributed around the circle at equal angles. But how can i make this ?

2- How can i make the input of the cavity at the bottom of those two cylinders? , i cant make excitation !

Thank you so much.
Regards,,
Goher

Hello Gohar :

do you know any thing about sweep submenu of draw menu in HFSS ?
if you know , you can utilize it in this manner :

at first you draw a 2D plot of corrugations cross section on the top or bottom of your outter cylinder and then you choose "sweep along vector" from sweep menu .
at the end you should sweep your cross section along the desired vector you want and subtract the outter cylinder of the sweeped cross section .

good luck.