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<div class="">Hi Sabri, maybe you have modes of variability that slosh around inside your regional domain, reflect off the open boundaries, and accumulate energy.</div>
<div class="">My understanding is that Orlanski boundary condition will be free of reflection for a single internal mode only.</div>
<div class="">Other internal (or shallow water) modes may not be damped.  Adding a sponge layer may help.</div>
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</div>
<div class="">All of the above is speculation from someone who does not fully understand how Orlanski boundary conditions work.</div>
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<div class="">Dimitris</div>
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<div class="">On Sep 18, 2022, at 11:55 AM, Sabri MUTLU (MAM-ÇTÜE) <<a href="mailto:sabri.mutlu@tubitak.gov.tr" class="">sabri.mutlu@tubitak.gov.tr</a>> wrote:</div>
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<div class="">Hi Matt,</div>
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</div>
<div class="">Max. U velocity at the boundary becomes higher than 1 m/sec, and also the current very close to the boundary reaches unrealistic speeds.</div>
<div class="">But do not know why, since it happens after 8 days in the simulation.</div>
<div class="">obc_W_uVel_max value always increases with time. Maybe this is the problem. If it is, how to solve it?<br data-mce-bogus="1" class="">
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<div class="">Best.</div>
<div class="">Sabri</div>
<div class=""><br class="">
</div>
<hr id="zwchr" data-marker="__DIVIDER__" class="">
<div data-marker="__HEADERS__" class=""><b class="">Kimden: </b>"Matthew Mazloff" <<a href="mailto:mmazloff@ucsd.edu" class="">mmazloff@ucsd.edu</a>><br class="">
<b class="">Kime: </b>"mitgcm-support" <<a href="mailto:mitgcm-support@mitgcm.org" class="">mitgcm-support@mitgcm.org</a>><br class="">
<b class="">Gönderilenler: </b>18 Eylül Pazar 2022 19:16:57<br class="">
<b class="">Konu: </b>Re: [MITgcm-support] Can not run a regional model for long time<br class="">
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<div data-marker="__QUOTED_TEXT__" class="">You need to find out why it is becoming unstable. Have a look at the solution and see if you can see where and why it is blowing up.
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</div>
<div class="">Matt</div>
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<blockquote class="">
<div class="">On Sep 18, 2022, at 6:08 AM, Sabri MUTLU (MAM-ÇTÜE) <<a href="mailto:sabri.mutlu@tubitak.gov.tr" target="_blank" rel="nofollow noopener noreferrer" class="">sabri.mutlu@tubitak.gov.tr</a>> wrote:</div>
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<div class=""><span style="font-size:12pt" class="">Hi all,</span><br class="">
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<div class="">
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<br class="">
<div class="">As a newbie in this field, I need help for the following problem, which I have been trying to deal with for a long time.</div>
<br class="">
<div class="">I built a regional model for my thesis study. When I try to run it for 12 or more days, it gives "NaN" values after 8 or 9 days later in the model. </div>
<div class="">Could you please examine the following model configuration and give me an idea for possible solution?</div>
<br class="">
<div class="">(I had to choose Orlanski method since don't have any boundary condition to feed the model.)</div>
<br class="">
<div class="">Thank you in advance.</div>
<div class="">Sabri</div>
<br class="">
<div class="">
<div class=""> &PARM01</div>
<div class=""> viscAh=2.E-2,</div>
<div class=""> viscAz=1.5E-5,</div>
<div class=""> no_slip_sides=.TRUE.,</div>
<div class=""> no_slip_bottom=.TRUE.,</div>
<div class=""> diffKhT=2.E-2,</div>
<div class=""> diffKhS=2.E-2,</div>
<div class=""> diffKzT=2.E-5,</div>
<div class=""> diffKzS=2.E-5,</div>
<div class=""> f0=0.948E-4,</div>
<div class=""> implicitFreeSurface=.TRUE.,</div>
<div class=""> exactConserv=.TRUE.,</div>
<div class=""> implicitDiffusion=.TRUE.,</div>
<div class=""> implicitViscosity=.TRUE.,</div>
<div class=""> eosType = 'JMD95Z',</div>
<div class=""> tRef=22.2803,22.3383,22.3646,22.4220,22.5469,22.5081,21.0406,19.6075,18.3619,16.7902,15.8310,15.4016,15.3625,15.3935,15.4334,15.4465,15.4508,15.4710,15.5226,</div>
<div class="">      15.5428,15.5485,15.5589,15.5829,15.5860,15.5859,15.5767,15.5572,15.5477,15.5357,15.5068,15.4782,15.4640,15.4337,15.3816,15.3480,15.2998,15.2423,15.2127,</div>
<div class="">      15.1271,15.0639,15.0086,14.9722,14.9229,14.8937,14.8470,14.8073,14.7838,14.7677,14.7392,14.7210,14.7037,14.7036,14.7035,14.7034,14.7033,</div>
<div class=""> sRef=24.3775,24.4042,24.4730,24.5782,24.7042,24.8407,25.8279,26.4026,28.0163,30.1542,31.7531,33.9951,37.0132,37.5629,37.8303,37.9592,38.0011,38.1433,38.2744,</div>
<div class="">      38.3184,38.3548,38.4269,38.5535,38.6043,38.6738,38.7411,38.7479,38.7496,38.7510,38.7512,38.7469,38.7529,38.7569,38.7644,38.7666,38.7683,38.7698,38.7696,</div>
<div class="">      38.7635,38.7563,38.7513,38.7476,38.7427,38.7399,38.7354,38.7326,38.7305,38.7280,38.7254,38.7236,38.7220,38.7220,38.7220,38.7220,38.7220,</div>
<div class=""> staggerTimeStep = .TRUE.,</div>
<div class=""> tempAdvScheme = 33,</div>
<div class=""> saltAdvScheme = 33,</div>
<div class=""> useSingleCpuIO=.TRUE.,</div>
<div class=""> bottomDragQuadratic = 0.02,</div>
<div class=""> select_rStar = 0,</div>
<div class=""> &</div>
<br class="">
<div class=""> &PARM02</div>
<div class=""> cg2dMaxIters=300,</div>
<div class=""> cg2dTargetResidual=1.E-13,</div>
<div class=""> cg3dMaxIters=20,</div>
<div class=""> cg3dTargetResidual=1.E-8,</div>
<div class=""> &</div>
<div class="">---------</div>
<div class="">
<div class=""> &PARM03</div>
<div class=""> startTime  = 0.,</div>
<div class=""> endTime = 1036800.,</div>
<div class=""> deltaT=5,</div>
<div class=""> dumpFreq=10800.,</div>
<div class=""> monitorFreq=3600.,</div>
<div class=""> monitorSelect=2,</div>
<div class=""> periodicExternalForcing=.TRUE.,</div>
<div class=""> externForcingPeriod=10800.,</div>
<div class=""> externForcingCycle=1036800.,</div>
<div class=""> &</div>
<br class="">
<div class=""> &PARM04</div>
<div class=""> usingSphericalPolarGrid=.TRUE.,</div>
<div class=""> delz = 32*2,22*8,10,</div>
</div>
</div>
<div class="">
<div class=""> delX = 528*0.0013,</div>
<div class=""> delY = 164*0.001,</div>
<div class=""> ygOrigin=40.656,</div>
<div class=""> xgOrigin=29.2612,</div>
<div class=""> &</div>
<br class="">
<div class=""> &PARM05</div>
<div class=""> bathyFile='bathy_v6_528-164.bin',</div>
<div class=""> zonalWindFile='windU_2309-0510.bin',</div>
<div class=""> meridWindFile='windV_2309-0510.bin',</div>
<div class=""> &</div>
<br class="">
<div class="">
<div class=""># Open-boundaries</div>
<div class=""> &OBCS_PARM01</div>
<div class=""> OB_Iwest=164*1,</div>
<div class=""> useOrlanskiWest=.TRUE.,</div>
<div class=""> useOBCSbalance=.TRUE.,</div>
<div class=""> useOBCSsponge=.FALSE.,</div>
<div class=""> OBCS_balanceFacW = -1.,</div>
<div class=""> &</div>
<br class="">
</div>
</div>
<div class="">
<div class=""># Packages</div>
<div class=""> &PACKAGES</div>
<div class=""> useOBCS=.TRUE.,</div>
<div class=""> useKPP =.TRUE.,</div>
<div class=""> &</div>
</div>
</div>
<br class="">
</div>
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