How to simulate particles trajectory under dielectrophoretic force

Hi all,

Now I'm trying to trace the particles under dielectrophoresis(DEP) and laminar flow. I could apply DC but I can't apply AC. I can't make correlation among AC, laminar flow and dielectric force simultaneously. Here is the situation.

Model builder
study 1
>step 1:frequency domain (electric currents(AC))
>step 2:time dependent (laminar flow)
study 2
>step 1:time dependent (particle tracing for fluid flow)

study 2>
Values of dependent variables
□Values of variable for not solved for
Method: solution
Study: <<< I don't know which should I choose!

In study 2, It is impossible to choose "study 1:step 1" and "study 1:step 2" at the same time. How can I make the relation?
I already tried electric potential as "V*sin(2*pi*frequency*t)" instead of using frequency domain. But it doesn't work.

Thank you for reading.