how to couple nodes in rectangular tank

[ASDNET36]

hi,
iam studying the behavior of elevated rectangular tank, i try to make the coupling of nodes between tank walls and the fluid but there is problem.
it didn't couple in right way

please help me how can i make this couple

 

[rb1957]

"nodes" or "modes"

Quando Omni Flunkus Moritati

 

[ASDNET36]

couple nodes to male fluid structure interaction between tank wall and fluid.