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RE: Fourier Analysis

NN
Nill Ng, modified 1 Month ago.

Fourier Analysis

Youngling Posts: 2 Join Date: 4/16/15 Recent Posts
I am testing out the Fourier analysis feature in a very simplified model. Yet it does not work out for me. Here are what I have tried: -
(1) Model run without temperature and Fourier analysis - model run normally
(2) Model run without temperature and with Fourier analysis for water level (wl) - model run normally, Fourier map results include statistics of water level
(3) Model run without temperature and with Fourier analysis for current velocity (ux, uy) - model run cannot start
(4) Model run without temperature and with Fourier analysis for current velocity (uv, this is the old keyword used in Delft3D Classic)- model run normally, but without map output of Fourier analysis for current
(5) Model run with temperature and without Fourier analysis (ct) - model run cannot start
(6) Model run with temperature with Fourier analysis period start in the middle of the model - model run stop progressing in the middle of the modelling period
From (2)-(5) I can deduce the keywords wl, ux, uy and ct are probably right as stated in the DFM manual.  And from (3), (5) & (6) I can deduce the only reason with model not working is about the Fourier analysis for current and temperature.
The relevant setup are attached if anyone is interested to have a look.  There is nothing confidential there and the test run take only 20s on my PC.  I would love to hear from other users on the issue. My DFM version is 2018.04

Attachments:

Munawir Pratama, modified 24 Days ago.

RE: Fourier Analysis

Youngling Posts: 2 Join Date: 9/11/16 Recent Posts
Hi Nill,
Please try this file for your model.
It works for me, it is for curr velocity magnitude.
Cheers,
NN
Nill Ng, modified 16 Days ago.

RE: Fourier Analysis

Youngling Posts: 2 Join Date: 4/16/15 Recent Posts
Thank you Munawir. That works for me after changing the start time to 1200 instead of 2880 (because 2880 is not a multiple of user defined time step).Is there a reason why that my file do not work? Formatting aside, the difference is only about having the statistic start time to be slightly after the model start time (original statistic start time is 0).Or does the number of space between input matter? That does not seem to be included in the manual though.
Munawir Pratama, modified 1 Day ago.

RE: Fourier Analysis

Youngling Posts: 2 Join Date: 9/11/16 Recent Posts
Hi Nill,I believe the easy way to make .fou work is
1. to look up the mdu file, and
2. check the Tunit, DtUser, and Tstop settings.
3. you can use the number for the start and stop time in .fou file.
4. if the model works and produces fou output, then you can try to change the start time (in case you need spin up time in the model)

The default time step is 5 minutes, so if the Tunit is M; it should be the multiplication of 5 or if it is S; it should be the multiplication of 300. For template, I usually copy the number to excel and copy it back to .txt file so it looks better and ensure the tabs/spaces.Please let me know if this tips is work or not.Cheers! Good luck!