Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
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.
got problem with my simulation on nano scale particles
Posted 29.08.2013, 15:24 GMT-4 Low-Frequency Electromagnetics, Mesh Version 4.3a 6 Replies
Please login with a confirmed email address before reporting spam
The magnetic field is generated by a wire, conducted with steady current. The wire is about 30um in radius.
However, the iron particle is only 10 nm scale, much smaller than the wire. Seems difficult to define the mesh. Is it possible to simulate? Or is there any other method? Can I just define the distribution of the Magnetic field rather than modeling the wire?
Thank you in advance.
Jie
Please login with a confirmed email address before reporting spam
You could use scattered filed formulation to specify background (incident) plane wave in RF interface (emw) ant then use Maxwell stress tensor to calculate force as following:
Fx=intop1(emw.unTx)
Fy=intop1(emw.unTy)
Fz=intop1(emw.unTz)
where intop1(.) is boundary integration coupling operator over the particle surface.
Regards,
Sergei
Please login with a confirmed email address before reporting spam
By this method, I can define a magnetic field on a boundary, what I can decide is its direction, amplitude and frequency right? But here I would like to simulate a wire conducted with steady current. The magnetic field will be circular and decreasing with the distance. Can I define this kind of M field distribution by RF?
Thank you again and looking forward to your reply.
Jie
Please login with a confirmed email address before reporting spam
I have a question, what the difference between the emw.unTx and the emw.dnTx? How could I choose it?
And where can I find the information about the expression "emw.unTx", I can't find it in the comsol help document.
Thank you!
Best regards
Please login with a confirmed email address before reporting spam
Variable emw.unTx corresponds to Maxwell upward surface stress tensor and is calculated using normal vector up direction emw.unx.
Variable emw.dnTx corresponds to Maxwell downward surface stress tensor and is calculated using normal vector down direction emw.dnx.
These variables are defined under Equation view, as shown in the attached image. To visualize the directions of the normal vector up or down, create line plot of the corresponding vector components
For particle surrounded by air, use upward surface stress tensor components to calculate force on the particle.
If you want to calculate force on the air interface, use downward stress tensor.
Regards,
Sergei
Attachments:
Please login with a confirmed email address before reporting spam
Variable emw.unTx corresponds to Maxwell upward surface stress tensor and is calculated using normal vector up direction emw.unx.
Variable emw.dnTx corresponds to Maxwell downward surface stress tensor and is calculated using normal vector down direction emw.dnx.
These variables are defined under Equation view, as shown in the attached image. To visualize the directions of the normal vector up or down, create line plot of the corresponding vector components
For particle surrounded by air, use upward surface stress tensor components to calculate force on the particle.
If you want to calculate force on the air interface, use downward stress tensor.
Regards,
Sergei
Please login with a confirmed email address before reporting spam
Thanks, I have found the equation view.
My model is a dielectric sphere between the nanoparticle(Au material) and the nanorod(also Au material).
I want to calculate the force exerted on the dielectric sphere.
According to your suggestion, I should use the upward surface stress tensor components .But the results were 0(x,y and z component ).
If I use the downward stress tensor, I get the non-zero results.
Why ?It puzzled me.
Best regards
Zerong