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defining a piecewise function
Posted Feb 22, 2011, 9:53 a.m. EST Heat Transfer & Phase Change, Materials, Parameters, Variables, & Functions, Studies & Solvers Version 4.1 0 Replies
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I am currently attempting to use COMSOL to deal with the heat transfer associated with reentry on a body. I am attempting to curve fit heat flow influx data in MATLAB and then use it in COMSOL. The problem I am having is that I get a bad curve fit for the data because it changes so many orders of magnitude (no matter which function, including an exponential). I was really hoping to be able to define a piecewise function in COMSOL or in other words, be able to input different equations over different time ranges. I have tried using the piecewise function under global definitions so that I can use it wherever I want, but it says unknown variable. If I try to run it, it will fail with a jacobian error. I am using the default selections in the piecewise function section except changing the argument to t. I am new to COMSOL and having to teach myself to use the program so any suggestions anyone has would really be appreciated.
Thanks so much,
Zac
Hello Zac Cyree
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