# Plasma Process Error

I want to move the heat source across the length of the cylinder. I am not able to figure out how to do this? The problem is if I choose surface heat flux, then I have to choose a surface of the cylinder but I do not know how my equation works then. Does anyone have any suggestions?

Hi @nnandakumar,

Please post a appropriate title. I’ve changed it for you.

Project links should be in the post itself. Your project is here for everyone’s reference.

CHT is not my main area so maybe @jousefm or the other users can give you some advice. If I find anything I will be sure to post.

Cheers.

Regards,
Barry

Thank you for the help Hi @nnandakumar and @Get_Barried!

Not sure if you are looking for something like this: Thermal benchmark (steady state) - assuming that you have a cylinder and you want to validate your results.

Best,

Jousef

I want to do something similar to this:

but on the outer surface of a cylinder.

Hi @nnandakumar!

The project seems to be private - change the settings that we can see it or share it with us by using the username or mail address.

Cheers,

Jousef

Hey I changed it. You can see it now.

Hi @nnandakumar!

q = \frac{2P}{\pi r_0^2} exp\left(-\frac{2r^2}{r_0^2} \right)
• P is the power of laser, 2 kW in our case.
• r_o is the radius of laser beam, 0.003 m (3 mm) in our case.
• r = \sqrt{(x-x_o)^2+(y-y_o)^2} is the radial distance of the beam from any point. Here, x and y are x and y direction of the coordinate system respectively. xo and yo are the terms used for defining the motion. In our case, x_o = a + R*cos(2 \pi v_\alpha t) and y_o = b + R sin(2\pi v_α t), where;
• a and b are the x and y coordinates of the circle center, in our case (a,b)=(0,0).
• R is the radius of the circle, 0.035 m (3.5 cm) in our case.
• v_\alpha is the angular velocity of the beam, 0.167 \frac{rad}{s} in our case. The actual velocity of the beam can be calculated by v = 2\pi R v_\alpha which gives v ~ 0.037 \frac{m}{s} (~2.22 \frac{m}{min}.)
• t is time step which is 6 s for a full revolution with timestep length of 0.06 s in our case i.e. cos(2\pi) and sin(2\pi) occurs when v_\alpha*t = 0.167 \frac{rad}{s} x 6 s = 1 rad

Does this help? Cheers!

Jousef

I tried to use this equation but since I want to make the beam have helical motion on the outer surface of the cylinder, I am confused as to how to modify the equation and what coordinate system to use :(. I want to first start by just moving the beam in a straight line on the outer curved surface of the cylinder and then introduce also a circular motion. I hope that I am able to explain my idea clearly.

Sorry for the late response @nnandakumar!

I hope that I can have a look at your project later this day and get back to you as soon as know more.

Best,

Jousef

1 Like

was anyone able to find something out ?  Did not have the time so far @nnandakumar.

Let me tag my colleagues @BenLewis and @cjquijano here who might jump in in the meantime.

Best,

Jousef

https://www.simscale.com/projects/nnandakumar/tryyyy/

Like this but on a cylinder.