Evaluating electric field at interface

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Author Message   Leslie Yeo (icllymy) New member Username: icllymy Post Number: 1 Registered: 08-2004 Posted on Thursday, August 19, 2004 - 01:26 pm:    I am trying to determine the normal electric field En along an interface (region 2 or pathname "interface" in the attached files) by using EXPRESSION (En) on "interface". If region 2 is an arc, generated by using the ARC command, as in the file "drop.pde", this works fine. I get values of En along the interface. However, since I require complex drop shapes, I generate region 2 by a series of lines, as in the file "drop2.pde". However, because of the point-wise definition of the interface instead of the continuous definition using ARC, I get zero values for En along the interface. File for circular drop generated by ARC drop.pde (1.1 k) File for complex drop shape generated by line segments drop2.pde (3.3 k)   Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 213 Registered: 06-2003 Posted on Thursday, August 19, 2004 - 08:10 pm:    1. The electric field is discontinuous at a material interface, so it is important which side of the interface you compute the value on. Add an additional control "ON REGION 1" to your plot statement to force evaluation in the outer material. 2. In 2D Cylindrical geometries, FlexPDE rotates your figure 2.pi radians around the axis (r=0). Negative radii are meaningless. Cut your problem in half and mesh the part with only positive radii. 3. In version 4.1, you can use a spline boundary to smooth the curve of your interface. See SPLINE in the help index.