| Author |
Message |
    
Patricio A. Greco (pagreco)
New member
Username: pagreco
Post Number: 1
Registered: 08-2003
| | Posted on Sunday, August 17, 2003 - 02:02 pm: | |
In order to expand the sofware capability , I would like to know if there are the possibility to add two new functions for FFT argument and magnitude basically for time dependent variables.
It should simplify the study of frequency response for step or quasi-impulse exitation.
The FFT for space domain 2D is usefull to know for example the modal amplitude and phase distribution for an arbitrary exitation in a resonant cavity
Now I´m exporting the tables and made the calculation in other program , but I think that it should be implemented at the same program.
Thank you very much. |
Robert G. Nelson (rgnelson)
Member
Username: rgnelson
Post Number: 16
Registered: 06-2003
| | Posted on Sunday, August 17, 2003 - 08:16 pm: | |
I'm not sure I understand the question.
FlexPDE is frequently used for harmonic analysis of cavity resonators and waveguides. You just need to substitute the complex exponential u=u0*exp(-i*omega*t) into the PDE.
See:
"Backstrom_Books | Fields_of_Physics | d_heat | wave1.pde"
or "Samples | Time_Dependent | Stress | Harmonic.pde",
or "Samples | Eigenvalues | waveguide.pde".
Or do you mean that you want FlexPDE after the fact to calculate an (x,y,t) FFT of the solution of a transient problem? This would not be a steady oscillatory solution, but a transient. It would also require a simple rectangular 2D domain.
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Patricio A. Greco (pagreco)
New member
Username: pagreco
Post Number: 2
Registered: 08-2003
| | Posted on Sunday, August 17, 2003 - 09:23 pm: | |
The idea is to use FFT in trasident analysis.
I got good results using this method for wideband applications for example a waveguide filter. |
Mongi Mansouri (mongim_pde)
Member
Username: mongim_pde
Post Number: 9
Registered: 11-2003
| | Posted on Sunday, December 28, 2003 - 12:16 pm: | |
Hi all... I am using FlexPDE 2.22.
I have just found out that the export tool in FlexPDE does not keep all the data saved to an ascii file. After a long time it begins saving data starting from a later time point and forgets about all the previous data... I don't understand this. Is this an intended feature or is it a bug? The program should keep all the data saved in text files!! After running my program for two days, I was disappointed to find that my export files did not have all the data saved. Whare did all my data go? Is there a way to tell FlexPDE to keep all the info saved in ascii files? This is really a big problem. Hope you can help... Thank you. /Mongi M.
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