Note: This discussion is about an older version of the COMSOL Multiphysics® software. The information provided may be out of date.
Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.
How to induce temperature-dependent variable in HTS cable model
Posted 2012年7月28日 GMT-4 10:34 Heat Transfer & Phase Change Version 4.2 1 Reply
Please login with a confirmed email address before reporting spam
I am new to COMSOL, and i am trying to model of ac losses in HTS cable. Firstly, i have already implemented T-independent model, which assumes Jc and alpha as constant. In this assumption, the comsol can work well. However, now i need to consider the effects of temperature on Jc and alpha. I simply change the Jc and alpha from parameters to variables. It encountered a problem:
Feature:Time-Dependent Solver1(sol1/t1)
Error: Failed to evaluate expression.
Checking the Error, it said
Attempt to evaluate real logarithm of negative number.
- Function: log
Failed to evaluate temporary symbolic derivative variable.
However, i have clearly defined these variables in Model1. Hope someone can help me.
Feature:Time-Dependent Solver1(sol1/t1)
Error: Failed to evaluate expression.
Checking the Error, it said
Attempt to evaluate real logarithm of negative number.
- Function: log
Failed to evaluate temporary symbolic derivative variable.
However, i have clearly defined these variables in Model1. Hope someone can help me.
1 Reply Last Post 2012年8月6日 GMT-4 09:53
Please login with a confirmed email address before reporting spam
Posted:
1 decade ago
Hallo Anlong,
it tells you that it tries to compute the log from a negative nuimber. Look where you use
log and make sure its argument never becomes negative.
Jens
it tells you that it tries to compute the log from a negative nuimber. Look where you use
log and make sure its argument never becomes negative.
Jens