This question is not clear. What have you done so far? What do you want to do?

You may want to check the writing and spelling of the question.

Hi

lets say i want to use frequency domain how can i aplly AC voltage source in comsol,

Thanks

What i am trying to do is to simulate Uniderctional surface acoustic wave sensor(SAW)

I have piezoelectric subtrate and liquid half space on it, thats whay i am using acoustic-piezoelectric interaction, but i am confused, as i have to apply ac voltage sources like,  V0*sin(2*pi*f0*t) to piezoelectric substrate, should i use time-dependent study , if i use freuency domain study how can i apply ac signal in comsol

i hope  i did not confuse  you too

Thanks again..

Which physics are you using?

If you are using the proper physics, your voltage source is sinusoidal by default and you only need to give its amplitude and frequency. There is no variable t because it is frequency domain.

Hi

Now im usin piezo-acoustic freaquency domain in COMSOL, i did what you said, but there is another problem, i applied voltage source via electric circuit physics in comsol, and threre is error like DAE is sturcturally inconsistent..?

thanks a lot

I can't give proper advice since I am unfamiliar with the problem domain. You should contact COMSOL tech support.