Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Optimization with Particle Tracing Module

Please login with a confirmed email address before reporting spam

Hi everyone,

As mentioned, I would like to use COMSOL's optimization module to apply to Particle Tracing for Fluid Flow physics interface. The model refers to "Acoustic Levitator" of the model libraries. The model solves the Pressure Acoustics, Frequency Domain to calculate the pressure p, then apply this interface on Particle Tracing for Fluid Flow to trace the trajectories of the particles. Two studies are used included: Study 1 for Frequency Domain (calculate pressure in Acoustic Pressure, Frequency Domain interface), Study 2 for Time Dependent (trace the particle's position in Particle Tracing for Fluid Flow).

The optimization is maximizing Laplacian of acoustophoretic potential energy (in Particle Tracing Module) at a specific point. To do that, I've used the probe objective with the expression d(d(fpt.Urad),x),x)+d(d(fpt.Urad),y),y) with a random probe coordinates. I've also used the Global Control Variable to define the phase of the transducer (initial value= 60[deg]; bound range from -180[deg] to 180[deg]). However, when computing, it is said the "Only the BDF solver support analytic gradient". Therefore, I try "BDF" and "Initialization only" in the "Time-Dependent Solver" but none of them works.
I' ve tried to plot the particle trajectories with the above expression and the plot works well. I suspect the problem is because of the mathematical expression of potential energy fpt.Urad contains two terms that are in the form of real(a*conj(b)) but I'm not so sure. So the question is why I can't perform the optimization and do you have any suggestions?

I would very much appreciate if anyone could help me. The attached below are some settings in the model.

Sincerely,
Quoc


1 Reply Last Post Mar 28, 2017, 10:02 a.m. EDT
COMSOL Moderator

Hello Quoc Pham

Your Discussion has gone 30 days without a reply. If you still need help with COMSOL and have an on-subscription license, please visit our Support Center for help.

If you do not hold an on-subscription license, you may find an answer in another Discussion or in the Knowledge Base.


Please login with a confirmed email address before reporting spam

Posted: 7 years ago Mar 28, 2017, 10:02 a.m. EDT
I'm also trying to do that for an electrostatics problem. I didn't find any physics interface for solving equation of motion for particles. So I'm trying to implement the equation motion of particles using the mathematics module with force calculated from the electric field. But I'm confused about the physics interface I should be using. Any idea what I should use? Is there an easier way to do this?

Edit: I found the module. Sorry for bothering you.
I'm also trying to do that for an electrostatics problem. I didn't find any physics interface for solving equation of motion for particles. So I'm trying to implement the equation motion of particles using the mathematics module with force calculated from the electric field. But I'm confused about the physics interface I should be using. Any idea what I should use? Is there an easier way to do this? Edit: I found the module. Sorry for bothering you.

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.