Discussion Forum

Hello Vasantharajan,
You can use a parametric curve, like in the attached screenshot, to specify a spiral.
Best,
Jeff

Hello Jeff,
Thanks for your suggestion, but that gives me a 1-D spiral. But I wish to draw a 2D structure like a coil. By your example, one could be able to draw a spiral with a known radial parameter, "s". But to draw a 2D spiral coil, we require two known parameters. Is there any option to use multiple parameters in the parametric curve?

I've attached you a picture, that gives the clear depiction.

Image courtesy: coil32.net/online-calculators/flat-spiral-pancake-tesla-coil.html

Hello Jeff Hiller,
I tried with two parameters and got a structure as like in the image after the union and converting to solid. Now, I wish to adjust the thickness of the solid. But, to do so, I've to change the parametric curves, union them and then convert to solid, each and every time. Instead, is there any option to define parameter for the new solid? So that, we can directly vary the parameter of the solid.

Yes, COMSOL does support parametric geometries. Please read the Introduction to COMSOL Multiphysics manual, version 5.2, accessed through the File > Help >Documentation menu: the busbar tutorial illustrates this.
Best,
Jeff

I will add that if you wish to have multiple spirals of different sizes in a single analysis (as opposed to multiple analyses with a single spiral each), the relatively recent concept of geometry parts is a very useful one. With geometry parts, you can define a geometry template that draws a parameterized object. You can then call that template multiple times with different values for the different parameters, thereby creating a complex geometry very quickly. See www.comsol.com/release/5.1/mesh-and-geometry .
The attached files illustrate this concept.

Thanks for the suggestions Jeff. Your file is with comsol 5.1, but I wok in 4.4 version. Is there any option to work out it in 4.4, in a similar trend as you suggested?

Hello,
Both files are in version 5.2, the current version.
The concept of geometric parts was introduced at version 5.1. It did not exist in earlier releases.
Best,
Jeff

Hello Jeff,
Thanks for the reply Jeff.
Is it possible for me to write an algorithm so that I could make a template of a solid geometry built using parametric curves?

And one more, though we could be able define a cylinder in a comsol, the geodesics it takes into account are Cartesian coordinates and not polar. So, is there any method or module by which we could be able to define a cylinder using cylindrical polar coordinates directly, instead of using Cartesian? I tried using "cylindrical coordinates" option from " coordinates" menu, but I could not be able to define a meshgrid in cylindrical polar system. Any suggestions.

Regarding your first question: if your license includes LiveLink for MATLAB, you could certainly write such a program. But bear in mind that that capability exists out of the box in 5.2, so it may not make sense to invest time and resources into reinventing that wheel. There are of course many other reasons to upgrade to 5.2 to consider in making that decision.

Regarding your second question: I do not understand it, so I'll leave it to others to chime in.

Best,
Jeff

Thanks for your suggestion Jeff. I will surely consider about it.
I wish to elaborate the second question that I've asked in earlier reply.

Whenever we design any geometry in comsol, the grids inside geometry are rectangular using x and y coordinates. Instead, I wish to draw a circle in polar grids (using radial and theta coordinates). Is it possible in 4.4?

Image link: en.wikipedia.org/wiki/Log-polar_coordinates

regards,
Vasanth