Hello. Firstly, greetings to everyone, I am new here.
So, I am trying to build a model based on this article:
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&ved=0CCoQFjAB&url=http%3A%2F%2Fwww.victoria.ac.nz%2Fscps%2Fabout%2Fstaff%2Fpdf%2FElectrostatic-calibration-of-spheresphere-forces.pdf&ei=jF19UIPEL9ORhQfbsYC4AQ&usg=AFQjCNHvsG40c8nlNlCR3yx7YKBfey-tXw&sig2=HC5XPGRvo0qippVGnfngLg
I am also new to electrostatic modeling, but I have some basic Comsol knowledge.
My model contains two copper spheres with potentials Va and Vb and a large sphere representing surrounding medium (vacuum). I have selected Force Calculation domain condition and I tried Electric Potential and Terminal boundary conditions on the spheres.
In the article, it is described: '' When Va=Vb the force is repulsive at all distances, otherwise the force becomes attractive when the approach is close enough. Attraction occurs between spheres both at positive potential because of mutual polarization: for spheres with equal radii, the sphere at lower potential obtains a negatively charged region neighbouring the other sphere.''
I tried many different settings and I can't seem to get the described result, especially the reversal of the force direction. Am I missing something fundamental or just any detail? Is this a phenomenon that can be modeled using Comsol?
Regards,
Tomi
So, I am trying to build a model based on this article:
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&ved=0CCoQFjAB&url=http%3A%2F%2Fwww.victoria.ac.nz%2Fscps%2Fabout%2Fstaff%2Fpdf%2FElectrostatic-calibration-of-spheresphere-forces.pdf&ei=jF19UIPEL9ORhQfbsYC4AQ&usg=AFQjCNHvsG40c8nlNlCR3yx7YKBfey-tXw&sig2=HC5XPGRvo0qippVGnfngLg
I am also new to electrostatic modeling, but I have some basic Comsol knowledge.
My model contains two copper spheres with potentials Va and Vb and a large sphere representing surrounding medium (vacuum). I have selected Force Calculation domain condition and I tried Electric Potential and Terminal boundary conditions on the spheres.
In the article, it is described: '' When Va=Vb the force is repulsive at all distances, otherwise the force becomes attractive when the approach is close enough. Attraction occurs between spheres both at positive potential because of mutual polarization: for spheres with equal radii, the sphere at lower potential obtains a negatively charged region neighbouring the other sphere.''
I tried many different settings and I can't seem to get the described result, especially the reversal of the force direction. Am I missing something fundamental or just any detail? Is this a phenomenon that can be modeled using Comsol?
Regards,
Tomi