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Simple integration with limits
Posted 8 ago 2016, 18:27 GMT-4 Parameters, Variables, & Functions, Results & Visualization 2 Replies
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Hi All,
I have a linear projection(located along the y-axis) giving the heat loss/unit length for a simple rectangular channel located on the same axis. I simply want to integrate along this linear projection, and for any given y-location be able to tell what the heat loss is up to that point in the channel. I can't find a good description of how to do this. Some people suggest something about using a PDE, others seem to use the dest operator, but I can't get either to work. Adding an integration component coupling just gives me the total integral from 0 to y_max. Using integrate (expr,var,lower limit,upper limit) as follows integrate(....,y,0,y) gives me the correct values at the endpoints (y=0 and y=y_max), but in between is just a linear extrapolation it appears.
Any tips?
Thanks,
Bryan
I have a linear projection(located along the y-axis) giving the heat loss/unit length for a simple rectangular channel located on the same axis. I simply want to integrate along this linear projection, and for any given y-location be able to tell what the heat loss is up to that point in the channel. I can't find a good description of how to do this. Some people suggest something about using a PDE, others seem to use the dest operator, but I can't get either to work. Adding an integration component coupling just gives me the total integral from 0 to y_max. Using integrate (expr,var,lower limit,upper limit) as follows integrate(....,y,0,y) gives me the correct values at the endpoints (y=0 and y=y_max), but in between is just a linear extrapolation it appears.
Any tips?
Thanks,
Bryan
2 Replies Last Post 9 ago 2016, 16:59 GMT-4
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Posted:
8 years ago
Hello Bryan,
See www.comsol.com/blogs/overview-integration-methods-space-time/ .
The portion about antiderivatives may be what you're looking for.
Best regards,
Jeff
See www.comsol.com/blogs/overview-integration-methods-space-time/ .
The portion about antiderivatives may be what you're looking for.
Best regards,
Jeff
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Posted:
8 years ago
Hi Jeff,
Thanks for the response. I had tried that without success before, but since you thought it work I gave it another shot and it worked. Now on to the next issue!
Thanks again,
Bryan
Thanks for the response. I had tried that without success before, but since you thought it work I gave it another shot and it worked. Now on to the next issue!
Thanks again,
Bryan