IES4104 Modelling and Design

IES4104 Modelling and Design

Assignment 1 is aimed at introducing Comsol Mulitphysics. The subject and physics of electric fields should be familiar to all students. To complete this assignment, you will have to understand the nature of the problem being set (Electrostatics) and know how to create a simulation in Comsol Multiphysics. Students should also make some effort towards minimising the problem by using planes of symmetry and increasing solution accuracy by refining the modelling mesh. Before starting this assignment, students should have attended the lab sessions (lab 1,2,3), read and follow the tutorials provided with Comsol Multiphysics to teach themselves how to use the software, create models and extract results. Students should also look at the sample models, especially those for AC/DC electrical systems. Explanation of the physics/Maths being employed in this assignment can be found in the guidance notes (Chapters 1, 6, 8) on Blackboard as well as text books (See notes Chapter 9 for possible references) available in the library.

Tasks. Use Comsol Multiphysics to perform a 2D simulation of the electrodes in figure 1. Find the electric potential and the electric field strength distribution in the region between the electrodes. Using information that can be gained from the module notes, consider how the problem can be reduced to be as simple as possible (It can be drawn with 8 lines and 4 curves). Use Comsol multiphysics to investigate the 2D model and find out what influence the radius of the corner has on the electric field around the corners of the electrodes. Similarly, what influence does the density of your simulation mesh have on your results? Next, assuming the electrodes are 5 μm thick, perform a 3D simulation of the electrodes to find the electric potential and electric field distribution in a plane 20 μm above the electrodes. For this simulation, assume that the oil extends at least 80 μm above and below the electrodes. Use Comsol Multiphysics to investigate the 3D model and find out what influence the distance the oil extends above and below the electrodes has on the shape of the electric potential and field distribution.

You are required to work individually on this assignment and submit a factual report on your simulations. This report should draw on knowledge from other modules or previous studies where appropriate and should consist of:

A short introduction describing the aim of the project.

A brief background information section describing only essential background physics or mathematics required to understand this specific problem.

A method section describing how your model was created along with any physics, boundary and subdomain settings. You should explain why each boundary and subdomain parameter has been chosen. Describe the boundary/physics/subdomain NOT THE ACTION YOU PERFORMED IN THE SOFTWARE

A Results section presenting and describing your findings in a clear and concise manner. The data that answers any specific questions in this document should be presented here along with simulations that have been used to understand the assignment tasks. All graphs/images must be clearly readable.

A discussion section presenting a detailed explanation for your observations from the modelling exercise. You should also include in your discussion any evidence from literature that confirms or contradicts your findings. This section should also explain the answers to any specific questions asked in this document

A short conclusions section that summarises the work carried out and key findings from the work

A references section containing full references to any information sources you will, of course, have used in your work

Your report should have a similar structure to a scientific journal publication or book chapter. It may help you to imagine that the report is to become a published paper. Ask yourself what information is necessary for someone else to reproduce your work and what is the best way to clearly and concisely present and fully explain your findings? The reader of the report may not have the same software as you to reproduce your model so your report should describe your work in nonsoftware specific ways. For instance, describe the physics and maths that you are simulating not the actions you undertook in the software. Remember the reader of your report needs to be told what your results are and why they occur