meet trouble with GLS_MIXING

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FengZhou
Posts: 52
Joined: Wed Apr 07, 2004 10:48 pm
Location: 2nd Institute of Oceanography,SOA

meet trouble with GLS_MIXING

#1 Unread post by FengZhou »

Hi, ROMSers,

Normally I used k-e (or k-omega) as my default GLS_MIXING scheme while applied ROMS(3.0) to the Bohai Sea (a small north part of the East China Sea). It performs better than others like k-kl, gen, and KPP. So I did the same choice while applied the model(3.1) to the whole East China Sea including the Changjiang river (Yangtze River). But it blows up after 2-3 days simulations, by contrast, there is no problem with KPP and MY25 for more than 1 years at least.

Does the k-e scheme have more strict limitations of the stability?

platform:
Linux node65 2.6.16.60-0.27-smp #1 SMP Fri Nov 28 21:47:49 CST 2008 x86_64 x86_64 x86_64 GNU/Linux
vendor_id : AuthenticAMD
cpu name : Quad-Core AMD Opteron(tm) Processor 8350

model version:
svn: $LastChangedDate: 2008-12-24 11:42:42 +0800 (Wed, 24 Dec 2008) $
svn: $Id: Version 291 2008-12-24 03:42:42Z arango $

compiler:
PGI

Thank you in advance!

zhou

jcwarner
Posts: 1198
Joined: Wed Dec 31, 2003 6:16 pm
Location: USGS, USA

Re: meet trouble with GLS_MIXING

#2 Unread post by jcwarner »

there really should not be substantial differences in GLS between roms 3.0 and 3.1. One thing you could do is look at the gls_corstep.f90 files that are generated during the Build, and compare them between the two versions.

jacopo
Posts: 81
Joined: Fri Nov 21, 2003 9:30 pm
Location: CNR-ISMAR

Re: meet trouble with GLS_MIXING

#3 Unread post by jacopo »

I experienced too that k-e is less stable than others schemes. In several realistic applications I did, the model runs OK if using MY25, k-w, gen but it blows up with k-e using the very same time step. With a reduced time-step, k-e works fine. This problem occurs mostly during spin up periods.

FengZhou
Posts: 52
Joined: Wed Apr 07, 2004 10:48 pm
Location: 2nd Institute of Oceanography,SOA

Re: meet trouble with GLS_MIXING

#4 Unread post by FengZhou »

Hi, John,

I don't know MPI well, so I just check others.

I don't think there are changes between these two versions by comparing Build/gls_corstep.f90.


zhou

ggerbi
Posts: 15
Joined: Thu Jun 12, 2008 6:03 pm
Location: University of Maine

Re: meet trouble with GLS_MIXING

#5 Unread post by ggerbi »

I found the same thing as jacopo. Reducing the time step made it run fine.
Have you tested it with all three stability functions (Kantha-Clayson, Canuto A and Canuto B?)

FengZhou
Posts: 52
Joined: Wed Apr 07, 2004 10:48 pm
Location: 2nd Institute of Oceanography,SOA

Re: meet trouble with GLS_MIXING

#6 Unread post by FengZhou »

Hi,
ggerbi wrote:I found the same thing as jacopo. Reducing the time step made it run fine.
Have you tested it with all three stability functions (Kantha-Clayson, Canuto A and Canuto B?)
As you said, Canuto A works.

Thank you!

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