Problem with BLOWUP REASON: MaxSpeed = 2.1E+01

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felipe.jbarragan7
Posts: 23
Joined: Tue Jul 04, 2023 3:22 pm
Location: Universidad de Antioquia

Problem with BLOWUP REASON: MaxSpeed = 2.1E+01

#1 Unread post by felipe.jbarragan7 »

Hi everyone, please somebody could help me with this problem.

I'm trying run this case called Test1, is for 1 year, but in this case is only 1 month (January 2014), the problem is that everytime the case stop for cause of this:
(' Blowing-up: Saving latest model state into RESTART file
REASON: MaxSpeed = 2.1E+01
WRT_RST_NF90 - wrote re-start fields (Index=1,1) in record = 3')


So, I don't really because it. I tried change time-step (Passed of 30 to 10 second), changed the DCRIT (of 0.1 to 2), but the problem still continue.
I'll append the caseout of cluster, .h and .in, if somebody could please help me to find the problem, i thankful it.

Good day for all!
Attachments
roms_test1_case.txt
(55 KiB) Downloaded 245 times
test1.h
(943 Bytes) Downloaded 252 times
roms_test1.in
(156.32 KiB) Downloaded 299 times

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wilkin
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Location: Rutgers University
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Re: Problem with BLOWUP REASON: MaxSpeed = 2.1E+01

#2 Unread post by wilkin »

Your open boundary conditions don't make sense.

You have periodic conditions for u,v but a mix of closed and Flather conditions for ubar, vbar. If u,v is periodic then ubar,vbar must be also. Without knowing more about your grid it's hard to say what to do, but since you have MASKING defined I presume you have some sort of "realistic" set-up and it's unlikely you want periodic conditions for anything.

Look at the Courant number guidance:
Maximum barotropic Courant Number = 9.37921095E-01

You are very close to 1, so the barotropic time step set by dtfast = dt/ndtfast is close to, or actually, unstable. dtfast should be smaller.

Your NDTFAST of 10 is smaller than recommended. Make this larger (say, 30) to see if that helps, after you've set sensible open boundary conditions.

You have NaNs in the very first time step output. I say this so many times on the User Forum ..... you can't have any NaNs in your initial conditions or boundary data, not even in the land mask.

Check that. NaNs in land can be set to any real number and the masking will take care of it, but anything times NaN is Nan so they propagate out of the land mask and into the water.
John Wilkin: DMCS Rutgers University
71 Dudley Rd, New Brunswick, NJ 08901-8521, USA. ph: 609-630-0559 jwilkin@rutgers.edu

felipe.jbarragan7
Posts: 23
Joined: Tue Jul 04, 2023 3:22 pm
Location: Universidad de Antioquia

Re: Problem with BLOWUP REASON: MaxSpeed = 2.1E+01

#3 Unread post by felipe.jbarragan7 »

Thanks so much Dr. Wilkin for your suggestion and help.

I changed the boundary conditions based in the reality of case. (Is closed for East and South for the continent), but had the error in periodic conditions for u,v.
About the time-stepping parameters, changed based in his recommends.

Is very strange about the NaN data, I revised all the data and don't found nothing :(. I hope that now the case don't stop for this.

Thanks for the help, the case is running now and the results i'm looking better than before.

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