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Unformatted text preview: SUPPLEMENTARY HANDOUT: COMSOL GUIDE FOR 1-D This handout is designed to highlight some of the key features and set- tings that can be found in the menus of COMSOL. Remember that you can always get more background information in the “Help Desk”, which can be found in the Help drop down menu. 1 Opening a new problem • For a 1-D problem, select 1-D in the “space dimension” drop down. • The most general way to construct a 1-D problem is to use PDE Co- efficient mode, which can be found under the “Application Mode” → “COMSOL Multiphysics” folders. • Select either “Stationary” or “Time-dependent analysis”. 2 Options drop down menu • The first item listed is where you define the “Constants”. Here is where you can specify any constants that will remain fixed during your anal- ysis. Simply put the constant name, such as k, under “Name” and define its numeric value under “Expression”. The value will automat- ically appear under “Value”. You do not need to use = to assign constants. • The second item is where you define “Expressions”. For now we will just focus on “Global Expressions”. This is basically where you can define functions of the space and time variables. Simply put the name of the function under “Name”, and put the actual function itself under “Expression”. For example, if I wanted to define f = k 2 e x , where k has been defined in constants, then it would look like Table 1. • There are more features in this drop down menu, but they are not needed for your assignments 3 Draw drop down menu • The first item is the “Draw Object” option. If you select “Line”, this allows you to graphically create the geometry, by drawing the line 1 Name Expression f k ∧ 2*exp(x) Table 1: Defining an expression f. segment from end point to end point. But you cannot change the length after you create the line. (Very strange, I know) • The second item is “Specify Objects”. If you select line, this allows you to generate a line based on geometric coordinates. For example, if you specify 0, 1 in the “Coordinates” field, it will generate a single line from 0 to 1. But if you specify 0, .5, 1 in the “Coordinates” field, then it will generate a line that is constructed of a segment that goes from 0 to 0.5 and another that goes from 0.5 to 1. COMSOL knows that these are continuous, so it will only make the right and left most...
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This note was uploaded on 08/01/2008 for the course ME 180 taught by Professor Zohdi during the Spring '08 term at Berkeley.
- Spring '08