[MITgcm-support] MITgcm-support Digest, Vol 257, Issue 9
赖六娃
yhlai at pku.edu.cn
Sat Nov 16 02:13:41 EST 2024
Hi Martin,
Thanks very much for your helpful suggestions. Probably I need to use stronger vertical viscosity to check if the simulation would be stable in this case or not. And to satisfy other stability conditions, I may need to use implicit schemes for vertical viscosity. Actually, the viscosity of molten silicates (magma ocean) is comparable to that of seawater, but I can use larger viscosity for solid silicates. Also, I will try to use bottom drag or no slip bottom, rather than both of them.
Best,
Yanhong
> 2024年11月15日 18:31，mitgcm-support-request at mitgcm.org 写道：
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> Today's Topics:
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> 1. Re: Numerical instability when horizontal contrast of initial
> temperature is large (Martin Losch)
> 2. Re: Numerical instability when horizontal contrast of initial
> temperature is large (Giordano, Fabio)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Fri, 15 Nov 2024 10:46:10 +0100
> From: Martin Losch <Martin.Losch at awi.de>
> To: MITgcm Support <mitgcm-support at mitgcm.org>
> Subject: Re: [MITgcm-support] Numerical instability when horizontal
> contrast of initial temperature is large
> Message-ID: <734E7448-CF3A-45E5-A099-B21169F42382 at awi.de>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Yanhong,
>
> it?s very difficult to say because your setup involves many parameters that are untypical for Earth (where we have more experience).
>
> I would check your CFL numbers for advection ( u * dt / dx ), viscosity Ah dt/dx**2 (here I would use AhGrid < 1 to make sure that this part is stable), also vertical viscosity. I agree with Christoph, that the viscosity appears a little low. But you may need viscosities that are large and maybe require implicit schemes that are only available for the vertical (in MITgcm). The Coriolis CFL number is probably also much different from Earth, so is gravity.
>
> Then you horizontal density gradients are probably huge leading to large flow velocities, right? Again large viscosities will be required to balance that.
>
> (don?t use bottom drag and no_slip_bottom together, it?s double counting the effect of the bottom)
>
> Martin
>
>> On 15. Nov 2024, at 08:43, Christoph Voelker <christoph.voelker at awi.de> wrote:
>>
>> Dear Yanhong,
>>
>> I have no idea what to choose as viscosity for a magma ocean, but I wondered about the viscosities: In the tutorial examples, which are made for water, one finds values like
>>
>> viscAr=1.E-3,
>> viscAh=5.E5,
>>
>> not so different from what you take. Should these values not be very much higher for Magma?
>>
>> Also, how are you prescribing the equation of state?
>>
>> Cheers, Christoph
>>
>>
>> On 15.11.24 08:31, ??? wrote:
>>> Hi,
>>> I?m trying to simulate the magma ocean in tidally locked lava planet.
>>> To speed up the simulation, the initial temperature is set to decrease from 3000 K at the substellar point (0,0) to 50 K at the side boundaries.
>>> Meanwhile, the initial temperature is vertically uniform.
>>> However, there is strong instability when I start this simulation. I tried to decrease the maximum initial temperature to 1700 K, and the horizontal contrast becomes to (1700-50) K, but it is still unstable.
>>> Is there any way I can simulate stably with this initial temperature setup?
>>> By the way, the tilmestep deltaT is 20 s.
>>> Thanks very much!!
>>> Yanhong
>>> Below is my data file:
>>> # ====================
>>> # | Model parameters |
>>> # ====================
>>> #
>>> # Continuous equation parameters
>>> &PARM01
>>> # tRef= 18.8, 16.3, 13.1, 10.4, 8.1, 6.0, 4.5,
>>> # 3.4, 2.7, 2.2, 1.8, 1.5, 1.2, 1.0, 0.9,
>>> tRefFile='T0solid_diffusion_160x72.bin',
>>> # tRef=44*1600.,
>>> sRef= 44*34.7,
>>> cosPower=1.,
>>> viscAr=1.E-3,
>>> viscAh=12.E5,
>>> no_slip_sides=.FALSE.,
>>> no_slip_bottom=.TRUE.,
>>> bottomDragLinear=1.E-3,
>>> #diffK4T=2.E12,
>>> diffKhT=1.E3,
>>> diffKrNrT=44*1.E-4,
>>> ivdc_kappa=100.,
>>> implicitDiffusion=.TRUE.,
>>> # eosType='JMD95Z',
>>> eosType='LINEAR',
>>> tAlpha=4.E-5,
>>> sBeta =0.E-4,
>>> saltStepping=.FALSE.,
>>> gravity=22,
>>> rhonil=3300.,
>>> rhoConst=2600.,
>>> HeatCapacity_Cp=1800.,
>>> implicitFreeSurface=.TRUE.,
>>> nonlinFreeSurf=4,
>>> select_rStar=2,
>>> hFacInf=0.2,
>>> hFacSup=2.0,
>>> exactConserv=.TRUE.,
>>> staggerTimeStep=.TRUE.,
>>> useCDscheme=.TRUE.,
>>> readBinaryPrec=64,
>>> tempAdvScheme=77,
>>> # usePickupBeforeC54=.TRUE.,
>>> rotationPeriod=69120.,
>>> # useCoriolis=.FALSE.,
>>> Tsolidus=1700.,
>>> Tliquidus=2000.,
>>> &
>>> # Elliptic solver parameters
>>> &PARM02
>>> cg2dMaxIters=1000,
>>> #cg2dTargetResidual=1.E-13,
>>> cg2dTargetResWunit=1.E-17,
>>> &
>>> # Time stepping parameters
>>> &PARM03
>>> niter0=0,
>>> nTimeSteps=20000000,
>>> #endTime=3110400000.,
>>> deltaT=10.0,
>>> # deltaTmom=100.0,
>>> # deltaTfreesurf=2000.0,
>>> # deltaTtracer=600.0,
>>> # deltaTClock =600.0,
>>> forcing_In_AB=.FALSE.,
>>> abEps=0.1,
>>> tauCD=321428.,
>>> tauThetaClimRelax=2000.0,
>>> # pickupStrictlyMatch=.FALSE.,
>>> chkptFreq=0.0,
>>> pChkptFreq=5000000.0,
>>> taveFreq=0.0,
>>> dumpFreq=5000000.0,
>>> diagFreq=31104000000.0,
>>> monitorFreq=31104000000.0,
>>> # monitorFreq=1.0,
>>> monitorSelect=2,
>>> &
>>> # Gridding parameters
>>> &PARM04
>>> usingSphericalPolarGrid=.TRUE.,
>>> # delRc= 20., 60., 85., 120., 165., 215., 265., 315.,
>>> # 365., 415., 465., 515., 565., 615., 665., 350.,
>>> # delRcFile='delRc.bin',
>>> delR= 10., 10., 10., 10., 10., 10., 10., 10., 10., 10., 20., 20., 20., 20., 20., 20.,
>>> 40., 40., 40., 40., 40., 60., 60., 60., 60., 80., 80., 80., 100., 100., 100., 100.,
>>> 100., 150., 150., 200., 200., 200., 200., 200., 300., 300., 300., 400.,
>>> rSphere=9E6,
>>> ygOrigin=-81.,
>>> xgOrigin=-180,
>>> delY=72*2.25,
>>> delX=160*2.25,
>>> &
>>> # Input datasets
>>> &PARM05
>>> bathyFile='topo3D_160x72_5400m_4walls.bin',
>>> # zonalWindFile='taux_Az1E-5mod_160x72.bin',
>>> # meridWindFile='tauy_Az1E-5mod_160x72.bin',
>>> thetaClimFile='sst3D_mod_160x72.bin',
>>> &
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org
>>> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
>>
>> --
>> Christoph V?lker
>> Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research
>> Am Handelshafen 12
>> 27570 Bremerhaven
>>
>> +49 (0)471-4831-1848
>> christoph.voelker at awi.de
>> https://orcid.org/0000-0003-3032-114X
>>
>> _______________________________________________
>> MITgcm-support mailing list
>> MITgcm-support at mitgcm.org
>> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
>
>
>
> ------------------------------
>
> Message: 2
> Date: Fri, 15 Nov 2024 11:30:55 +0100
> From: "Giordano, Fabio" <fgiordano at ogs.it>
> To: mitgcm-support at mitgcm.org
> Subject: Re: [MITgcm-support] Numerical instability when horizontal
> contrast of initial temperature is large
> Message-ID:
> <CAF=Mhuah0m6jqTE4pmW6DY13bO8A1jziE_7JJaTwx9pmmR+PPA at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Hi Martin,
> I would like to chime in about the bottom drag issue: does the double
> counting occur by setting the logical parameter `no_slip_bottom` to TRUE
> together
> 1) with non-zero linear or quadratic drag coefficients, or
> 2) only with the linear one?
> I am looking at the source code and by my understanding it seems to be the
> latter, but I could be mistaken.
>
> Thank you,
>
> Fabio Giordano
> Sezione di Oceanografia
> Istituto Nazionale di Oceanografia e di Geofisica Sperimentale - OGS
> via Beirut n. 2
> 34151 Trieste - Italia
>
> Il giorno ven 15 nov 2024 alle ore 10:46 Martin Losch <Martin.Losch at awi.de>
> ha scritto:
>
>> Hi Yanhong,
>>
>> it?s very difficult to say because your setup involves many parameters
>> that are untypical for Earth (where we have more experience).
>>
>> I would check your CFL numbers for advection ( u * dt / dx ), viscosity Ah
>> dt/dx**2 (here I would use AhGrid < 1 to make sure that this part is
>> stable), also vertical viscosity. I agree with Christoph, that the
>> viscosity appears a little low. But you may need viscosities that are large
>> and maybe require implicit schemes that are only available for the vertical
>> (in MITgcm). The Coriolis CFL number is probably also much different from
>> Earth, so is gravity.
>>
>> Then you horizontal density gradients are probably huge leading to large
>> flow velocities, right? Again large viscosities will be required to balance
>> that.
>>
>> (don?t use bottom drag and no_slip_bottom together, it?s double counting
>> the effect of the bottom)
>>
>> Martin
>>
>>> On 15. Nov 2024, at 08:43, Christoph Voelker <christoph.voelker at awi.de>
>> wrote:
>>>
>>> Dear Yanhong,
>>>
>>> I have no idea what to choose as viscosity for a magma ocean, but I
>> wondered about the viscosities: In the tutorial examples, which are made
>> for water, one finds values like
>>>
>>> viscAr=1.E-3,
>>> viscAh=5.E5,
>>>
>>> not so different from what you take. Should these values not be very
>> much higher for Magma?
>>>
>>> Also, how are you prescribing the equation of state?
>>>
>>> Cheers, Christoph
>>>
>>>
>>> On 15.11.24 08:31, ??? wrote:
>>>> Hi,
>>>> I?m trying to simulate the magma ocean in tidally locked lava planet.
>>>> To speed up the simulation, the initial temperature is set to decrease
>> from 3000 K at the substellar point (0,0) to 50 K at the side boundaries.
>>>> Meanwhile, the initial temperature is vertically uniform.
>>>> However, there is strong instability when I start this simulation. I
>> tried to decrease the maximum initial temperature to 1700 K, and the
>> horizontal contrast becomes to (1700-50) K, but it is still unstable.
>>>> Is there any way I can simulate stably with this initial temperature
>> setup?
>>>> By the way, the tilmestep deltaT is 20 s.
>>>> Thanks very much!!
>>>> Yanhong
>>>> Below is my data file:
>>>> # ====================
>>>> # | Model parameters |
>>>> # ====================
>>>> #
>>>> # Continuous equation parameters
>>>> &PARM01
>>>> # tRef= 18.8, 16.3, 13.1, 10.4, 8.1, 6.0, 4.5,
>>>> # 3.4, 2.7, 2.2, 1.8, 1.5, 1.2, 1.0, 0.9,
>>>> tRefFile='T0solid_diffusion_160x72.bin',
>>>> # tRef=44*1600.,
>>>> sRef= 44*34.7,
>>>> cosPower=1.,
>>>> viscAr=1.E-3,
>>>> viscAh=12.E5,
>>>> no_slip_sides=.FALSE.,
>>>> no_slip_bottom=.TRUE.,
>>>> bottomDragLinear=1.E-3,
>>>> #diffK4T=2.E12,
>>>> diffKhT=1.E3,
>>>> diffKrNrT=44*1.E-4,
>>>> ivdc_kappa=100.,
>>>> implicitDiffusion=.TRUE.,
>>>> # eosType='JMD95Z',
>>>> eosType='LINEAR',
>>>> tAlpha=4.E-5,
>>>> sBeta =0.E-4,
>>>> saltStepping=.FALSE.,
>>>> gravity=22,
>>>> rhonil=3300.,
>>>> rhoConst=2600.,
>>>> HeatCapacity_Cp=1800.,
>>>> implicitFreeSurface=.TRUE.,
>>>> nonlinFreeSurf=4,
>>>> select_rStar=2,
>>>> hFacInf=0.2,
>>>> hFacSup=2.0,
>>>> exactConserv=.TRUE.,
>>>> staggerTimeStep=.TRUE.,
>>>> useCDscheme=.TRUE.,
>>>> readBinaryPrec=64,
>>>> tempAdvScheme=77,
>>>> # usePickupBeforeC54=.TRUE.,
>>>> rotationPeriod=69120.,
>>>> # useCoriolis=.FALSE.,
>>>> Tsolidus=1700.,
>>>> Tliquidus=2000.,
>>>> &
>>>> # Elliptic solver parameters
>>>> &PARM02
>>>> cg2dMaxIters=1000,
>>>> #cg2dTargetResidual=1.E-13,
>>>> cg2dTargetResWunit=1.E-17,
>>>> &
>>>> # Time stepping parameters
>>>> &PARM03
>>>> niter0=0,
>>>> nTimeSteps=20000000,
>>>> #endTime=3110400000.,
>>>> deltaT=10.0,
>>>> # deltaTmom=100.0,
>>>> # deltaTfreesurf=2000.0,
>>>> # deltaTtracer=600.0,
>>>> # deltaTClock =600.0,
>>>> forcing_In_AB=.FALSE.,
>>>> abEps=0.1,
>>>> tauCD=321428.,
>>>> tauThetaClimRelax=2000.0,
>>>> # pickupStrictlyMatch=.FALSE.,
>>>> chkptFreq=0.0,
>>>> pChkptFreq=5000000.0,
>>>> taveFreq=0.0,
>>>> dumpFreq=5000000.0,
>>>> diagFreq=31104000000.0,
>>>> monitorFreq=31104000000.0,
>>>> # monitorFreq=1.0,
>>>> monitorSelect=2,
>>>> &
>>>> # Gridding parameters
>>>> &PARM04
>>>> usingSphericalPolarGrid=.TRUE.,
>>>> # delRc= 20., 60., 85., 120., 165., 215., 265., 315.,
>>>> # 365., 415., 465., 515., 565., 615., 665., 350.,
>>>> # delRcFile='delRc.bin',
>>>> delR= 10., 10., 10., 10., 10., 10., 10., 10., 10., 10., 20., 20., 20.,
>> 20., 20., 20.,
>>>> 40., 40., 40., 40., 40., 60., 60., 60., 60., 80., 80., 80.,
>> 100., 100., 100., 100.,
>>>> 100., 150., 150., 200., 200., 200., 200., 200., 300., 300.,
>> 300., 400.,
>>>> rSphere=9E6,
>>>> ygOrigin=-81.,
>>>> xgOrigin=-180,
>>>> delY=72*2.25,
>>>> delX=160*2.25,
>>>> &
>>>> # Input datasets
>>>> &PARM05
>>>> bathyFile='topo3D_160x72_5400m_4walls.bin',
>>>> # zonalWindFile='taux_Az1E-5mod_160x72.bin',
>>>> # meridWindFile='tauy_Az1E-5mod_160x72.bin',
>>>> thetaClimFile='sst3D_mod_160x72.bin',
>>>> &
>>>> _______________________________________________
>>>> MITgcm-support mailing list
>>>> MITgcm-support at mitgcm.org
>>>> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
>>>
>>> --
>>> Christoph V?lker
>>> Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research
>>> Am Handelshafen 12
>>> 27570 Bremerhaven
>>>
>>> +49 (0)471-4831-1848
>>> christoph.voelker at awi.de
>>> https://orcid.org/0000-0003-3032-114X
>>>
>>> _______________________________________________
>>> MITgcm-support mailing list
>>> MITgcm-support at mitgcm.org
>>> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
>>
>> _______________________________________________
>> MITgcm-support mailing list
>> MITgcm-support at mitgcm.org
>> http://mailman.mitgcm.org/mailman/listinfo/mitgcm-support
>>
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