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Using normal distribution to describe surface roughness

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Hi all,

I got a problem I would like to discuss here. I read many references which are talking about modeling of surface roughness, and one method is using normal distribution. Now I have the mean value and the standard deviation, I can write out the Probability Density Function (PDF). Now my question is still I dont have a clue on how to apply the PDF in comsol to describe a rough surface.

Could anyone give me some hints? Thanks in advance.

3 Replies Last Post 16 feb 2015, 11:49 GMT-5

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Posted: 1 decade ago 17 mag 2010, 08:58 GMT-4
Hi, is this to solve for light reflecting off the surface? Contact friction effects? Laminar fluid flow? Turbulent fluid flow? Etc.

If it is for turbulent fluid flow, then I have no clear idea how to do it, but would imagine that you would have to do much of the work yourself to determine how the roughness translated into wall conditions. Once you know the new wall conditions then you can type those in over the default equations in COMSOL. So the hard part is deriving new wall conditions. I am interested in those too - please post if you work anything out.

Regards, John


Hi, is this to solve for light reflecting off the surface? Contact friction effects? Laminar fluid flow? Turbulent fluid flow? Etc. If it is for turbulent fluid flow, then I have no clear idea how to do it, but would imagine that you would have to do much of the work yourself to determine how the roughness translated into wall conditions. Once you know the new wall conditions then you can type those in over the default equations in COMSOL. So the hard part is deriving new wall conditions. I am interested in those too - please post if you work anything out. Regards, John

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Posted: 1 decade ago 18 mag 2010, 03:13 GMT-4
hi?

this is for a mechanical wave traveling on a surface, therefore the surface roughness will scatter the propagation of the wave, i think it has nothing to do with the wall condition. I'm still working on it.
hi? this is for a mechanical wave traveling on a surface, therefore the surface roughness will scatter the propagation of the wave, i think it has nothing to do with the wall condition. I'm still working on it.

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Posted: 10 years ago 16 feb 2015, 11:49 GMT-5
Hey, Cheng,
Did you figure this problem out? I'm also working on this issue now. Could you give me some hints?
Hey, Cheng, Did you figure this problem out? I'm also working on this issue now. Could you give me some hints?

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