[Mesa-users] Does it need to consider convection when relaxing entropy?

[曾耀田]

DearRob,

    Thanksforyour reply!


   >>Areyousuretherelaxationprocesscompletedsuccessfully?

Iamnotsureiftherelaxingprocessiscompleteandsuccessful. Couldyou tellme howtodeterminethattherelaxingprocessissuccessful? SinceIdon'tknowhowtosaveprofilefilesduringtherelaxingprocess, now, to determinewhetherornotitissuccessful, thewaysItriedtousearetoseewhetherornotthepropertiesofamodelbecomestablebylookingatthepgstarwindowwhichcontainstemperature, entropy, density, pressure, andluminosityprofilesandsoon; andtocomparethedensity, internalenergy, andcompositionprofilesoftheinputmodelandthoseoffirstprofileafterrelaxingentropyfinishedwhenthemodelstartstoevolve. Nowthesituationisalthoughtheseprofilesofthemodelattheendoftherelaxingprocessbecomestableandthedifferenceofthedensity, internalenergy, andcompositionprofilesbetweentheinputmodelandfirstprofileissmall, themodelonlycanbeevolvedforawhilethenalwaysreturnthemessagethatcannotfindacceptablemodel. Anysuggestionsorideasonthisquestionwillbeappreciated.




>>tosavetheterminaloutputtolookbackandseeifthingsfinishproperly.

Isitpossibletotellmehowtoknowifthingsfinishproperly?




>>Thatisnotenoughinformation, whatisstrangeaboutit? Showaplot. Thoughingeneralyoushouldonlyworryiftheluminosityprofilelooking "strange" aftertheentropyrelaxationprocesshasfinished, notduringtherelaxprocess.

Iputtheinlist, figures, andrun.logfile forthree casesinattachments.

Thedifference betweencase_1andcase_2intheinlistis usingmin_T_for_acceleration_limited_conv_velocity = 0d0incase_2.

Thedifference betweencase_1andcase_3intheinlistis usingmixing_length_alpha = 0.0incase_3.

Manypeaksare shownontheluminosityprofile eventheendof the relaxingprocessincase_1butsomeofthem are notshownincase_2andcase_3. Andtheage_yrnolonger increasestoabout4d47yrsinthecase_2andcase_3. Inthecase_2andcase_3, thereare stillsomeproblemswiththeluminosityprofile .First ,therearedownwardsharppeaks. Idon'thaveaclueastohowthesepeakscomefrom. Second, theluminosityprofileisnotsmooth, itseemsthattherearesomeunstableregions, andIalsohavenoideahowtheunstable comesfrom. Anysuggestionsorideasonthisquestionwillbeappreciated.




>>NothinginappendixBofpaxton+ 2018suggestsastarcannotbeconvectivetorelaxtheentropy, theonlyrequirementismodelshouldbeinhydrostaticequilibrium. Butitisalsoalwaysusefultoexplicitlypointtowhereyoureadsomething (certainfile, publishedpaperetc) sowecanseeifitisamisunderstandingoranoutofdatedocument.

Sorryfor causing youmisunderstoodsinceIdidn'tdescribeclearly.I'mnewforMESA, therearemanythings (e.g. someoptionalcommands) Idonotunderstandandsometimesmisunderstand. ThatIgottheideawhichtoimportamodelintoMESAisfromappendixBofPaxton+ 2018.Intherelax_initial_entropyof star_jobdefaultsofthedocumentationforthemostrecentMESArelease (r12778), thereisasentencesay "Tocircumventconvection ... ". However, I do not clearly understand this. Soformycase, whatkindofthingsintheinlistshouldImodifytorelaxasuitablemodeltothenextevolving? Iwouldbeverygratefulifthereareanysuggestionsorideas.

Withbestwishes,

YaotianZeng

  

-----OriginalMessages-----
From:"RobFarmer" <r.j.farmer at uva.nl>
SentTime:2020-09-0323:43:47 (Thursday)
To: "曾耀田" <zengyaotian at ynao.ac.cn>
Cc:mesa-users <mesa-users at lists.mesastar.org>
Subject:Re: [Mesa-users] Doesitneedtoconsiderconvectionwhenrelaxingentropy?


Hi,
>Attheendoftherelaxingcomposition, theage_yrisincreasedto4d47yrs. Isthisreasonable?


Areyousuretherelaxationprocesscompletedsuccessfully? Itsoundslikethemodeldidnotsuccessfullyfinishtheentropyrelaxprocessleavingthestarinaninconsistentstate.


Youcouldrunyourmodelas



./rn | teerun.log


tosavetheterminaloutputtolookbackandseeifthingsfinishproperly.



>Andduringrelaxingentropy, theluminosityprofileappearedstrangesoItrytofigoutwhy.


Thatisnotenoughinformation, whatisstrangeaboutit? Showaplot. Thoughingeneralyoushouldonlyworryiftheluminosityprofilelooking "strange" aftertheentropyrelaxationprocesshasfinished, notduringtherelaxprocess.


>Thisseemstobeinconsistentwiththedescriptionofrelaxentropyinthemesadocument (maybemyunderstandingiswrong).


NothinginappendixBofpaxton+ 2018suggestsastarcannotbeconvectivetorelaxtheentropy, theonlyrequirementismodelshouldbeinhydrostaticequilibrium. Butitisalsoalwaysusefultoexplicitlypointtowhereyoureadsomething (certainfile, publishedpaperetc) sowecanseeifitisamisunderstandingoranoutofdatedocument.



> Ifoundwhenmixing_length_alpha = 0.0ormin_T_for_acceleration_limited_conv_velocity = 0d0 issetintheinlist, thesestrangeplaceintheluminosityprofiledisappears.


Againthereisnotenoughinformationtoidentifywhat "strangeplaceintheluminosityprofile" evenis. Showaplot.



Rob





OnThu, 3Sep2020at09:52, 曾耀田 <zengyaotian at ynao.ac.cn> wrote:


Dearall,

    I‘mtryingtoimporta3DHestarmodelwhichwasobtainedfromanSPHsimulationintoMESA. LikesaidintheMESAIVpaper (AppendixB), I'mtryingtousetherelaxationprocesstoachievethispurpose. I'musingthelatestversionofMESA (r12778). WhenrelaxingcompositionIfounditcanworkonlynum_steps_to_relax_composition = 500 . Attheendoftherelaxingcomposition, theage_yrisincreasedto4d47yrs. Isthisreasonable? Andduringrelaxingentropy, theluminosityprofileappearedstrangesoItrytofigoutwhy.  Ifoundwhenmixing_length_alpha = 0.0ormin_T_for_acceleration_limited_conv_velocity = 0d0 issetintheinlist, thesestrangeplaceintheluminosityprofiledisappears. itseemstheconvectionexistsduringtherelaxingentropy. Thisseemstobeinconsistentwiththedescriptionofrelaxentropyinthemesadocument (maybemyunderstandingiswrong). Sonow, I’mnotsurewhetherornottheconvectionshouldbeconsideredduringrelaxingentropy. Isthereanyonewhocanhelp?




Withbestwishes,

YaotianZeng




The  inlistIusedisshownbelow.


! inlist_relax

&star_job


    set_initial_dt = .true.
    years_for_initial_dt = 1d-4


    show_log_description_at_start = .true.
    show_net_species_info = .true.
    
    set_initial_cumulative_energy_error = .true.
    new_cumulative_energy_error = 0d0


    ! Relaxescomposition
    relax_initial_composition = .true.
    num_steps_to_relax_composition = 500
    relax_composition_filename = "composition.dat"
    
    relax_initial_entropy = .true.
    max_steps_to_relax_entropy = 1000
    timescale_for_relax_entropy = 1d-9 ! inyears
    max_dt_for_relax_entropy = 1d-9 ! inyears
    num_timescales_for_relax_entropy = 300
    relax_entropy_filename = "entropy.dat"
    get_entropy_for_relax_from_eos = 'eosDE'


    save_model_when_terminate = .true.
    save_model_filename = 'relaxed.mod'


    save_pgstar_files_when_terminate = .true.
    pgstar_flag = .true.


/ ! endofstar_jobnamelist


&controls

    !min_T_for_acceleration_limited_conv_velocity = 0d0

    initial_mass = 1.232d0

    !use_ledoux_criterion = .true.
    !mixing_length_alpha = 1.8
    !mixing_length_alpha = 0.0

    max_num_profile_models = 10
    profile_interval = 1
    history_interval = 1
    terminal_interval = 1
    write_header_frequency = 1


  ! stopwhenthecentermassfractionofh1dropsbelowthislimit
    ! max_age = 1d1
    xa_central_lower_limit_species(1) = 'he4'
    xa_central_lower_limit(1) = 1d-4


/ ! endofcontrolsnamelist


&pgstar


      
/ ! endofpgstarnamelist

 




-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20200904/83089103/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: case.zip
Type: application/zip
Size: 1838035 bytes
Desc: not available
URL: <https://lists.mesastar.org/pipermail/mesa-users/attachments/20200904/83089103/attachment-0001.zip>