- Email: [email protected]
CFD Investigation of Human Tidal Breathing through Human Airway Geometry
Procedia Computer Science Volume 80, 2016, Pages 965–976 ICCS 2016. The International Conference on Computational Science
&)'LQYHVWLJDWLRQRIKXPDQWLGDOEUHDWKLQJWKURXJK KXPDQDLUZD\JHRPHWU\ -DPDVS$]DUQRRVK.LGDPEL6UHHQLYDVDQG$EGROODK$UDEVKDKL The University of Tennessee at Chattanooga, Chattanooga, TN, USA [email protected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eywords:+XPDQDLUZD\V&)',QVSLUDWLRQ([SLUDWLRQ7UDQVLHQWEUHDWKLQJ
,QWURGXFWLRQ 7KHUHDUHKXQGUHGVRIPLOOLRQVRISHRSOHZRUOGZLGHZKRVXIIHUIURPFKURQLFUHVSLUDWRU\GLVHDVHV VXFK DV DVWKPD DQG FKURQLF REVWUXFWLYH SXOPRQDU\ GLVRUGHU &23' REVWUXFWLYH VOHHS DSQHD V\QGURPH 26$6 SXOPRQDU\ K\SHUWHQVLRQ HWF $OZDQ $ HW DO $LU SROOXWLRQ LV GLUHFWO\ FRQQHFWHG WR WKHVH LOOQHVVHV EHFDXVH RI WKHGHSRVLWLRQRI SDUWLFXODWH SROOXWDQWV LQ WKH OXQJV 7KHVH WR[LF SROOXWDQW SDUWLFOHV KDYH WKH SRWHQWLDO WR LQGXFH WKHVH GLVHDVHV 3DUWLFOH GHSRVLWLRQ LV
Selection and peer-review under responsibility of the Scientific Programme Committee of ICCS 2016 c The Authors. Published by Elsevier B.V.
doi:10.1016/j.procs.2016.05.392
965
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
PDLQO\DIIHFWHGE\WKHIORZILHOGZLWKLQWKHUHVSLUDWRU\V\VWHP7KHVHHIIHFWVDUHYHU\SURPLQHQWLQ WKHH[WUDWKRUDFLFDLUZD\ (7$ $QLQYHVWLJDWLRQUHSRUWHGWKDW±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
966
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
JHRPHWULHVXWLOL]HGLQPRVWRIWKHVHVWXGLHVZHUHOLPLWHGWRHLWKHUWKH(7$RUWKHORZHUDLUZD\RQO\ )RULQVWDQFH =KDQJ= .OHLQVWUHXHU& FRPSDUHGERWKWKHSHDNLQVSLUDWLRQDQGH[SLUDWLRQ YHORFLW\ SURILOHV IRU WKH :RPHUVOH\ QXPEHU Ƚ DQG IRXQG JRRG DJUHHPHQW ZLWK WKRVH RI LQVWDQWDQHRXVO\HTXLYDOHQWFRQVWDQWLQVSLUDWLRQH[SLUDWLRQFDVHV7KLVSDSHUIRFXVHVRQWKHHIIHFWVRI WKH(7$RQWKHORZHUDLUZD\ DQGYLFHYHUVD IRUDIXOOEUHDWKLQJF\FOHDQGFRPSDUHVWKHUHVXOWVRI WUDQVLHQW VLPXODWLRQV ZLWK VLPXODWLRQV FRUUHVSRQGLQJ WR FRQVWDQW LQVSLUDWLRQ DQG H[SLUDWLRQ 7R WKH EHVWRIWKHDXWKRUV¶NQRZOHGJHWKHVHFRPSDULVRQVKDYHQRWEHHQFDUULHGRXWE\DQ\UHVHDUFKHUIRU WKHHQWLUH FRPELQHG(7$ORZHU JHRPHWU\
0HWKRGV 7KHLGHDOL]HG(7$DQG&7EDVHGSXOPRQDU\DLUZD\JHRPHWU\ 7KH FRPSXWDWLRQDO (7$ JHRPHWU\ XWLOL]HG LQ WKLV VWXG\ LV EDVHG RQ WKH VRFDOOHG $OEHUWD (7$ PRGHOIURP8QLYHUVLW\RI$OEHUWD7KLVJHRPHWU\UHSUHVHQWVDPHDQRIWKHGLPHQVLRQVRIWKHXSSHU DLUZD\ZKLFKPLPLFVWKHFRPSOHWH(7$IURPWKHRUDOFDYLW\WRWKHWUDFKHDRIDQDGXOWKXPDQ7KH RYHUDOO KHLJKW LQFOXGLQJ WKH LQOHW QR]]OH DQG ZLGWK RI WKLV JHRPHWU\ DUH DQG PP UHVSHFWLYHO\ /LFHQVLQJ LVVXHV SUHYHQWHG WKH DFWXDO JHRPHWU\ IURP EHLQJ XVHG LQ WKLV SDSHU 7KH JHRPHWU\ XWLOL]HG LQ WKLV VWXG\ KDV EHHQ UHFRQVWUXFWHG EDVHG RQ WKH GHVFULSWLRQV DQG FURVVVHFWLRQV DYDLODEOHLQWKHOLWHUDWXUHIRULQVWDQFH +HHQDQHWDO -RKQVWRQHHWDO DQG =KDQJ< )LQOD\:+ 7KHJHRPHWU\ZDVFUHDWHGXVLQJ6ROLG:RUNVD'&RPSXWHU$LGHG'HVLJQ &$' PRGHOLQJSDFNDJH7KH(7$JHRPHWU\ZDVVFDOHGWRPDWFKZLWKWKH&7EDVHGORZHUDLUZD\V PRGHORI*UXHW]PDFKHU )LJXUHD WRSURYLGHWKHHQWLUHDLUZD\JHRPHWU\ )LJXUHEDQGF
)LJXUH D 7KH&7EDVHGORZHUDLUZD\JHRPHWU\EDQGF 7KHHQWLUHDLUZD\JHRPHWU\
%RWK JHRPHWULHV ZHUH PHVKHG XVLQJ 3RLQWZLVH YHUVLRQ 7KH VXUIDFH PHVK ZDV HQWLUHO\ VWUXFWXUHGDVWKLVKHOSHGUHGXFHWKHQXPEHURIVXUIDFHQRGHVFRPSDUHGWRXWLOL]LQJDQXQVWUXFWXUHG 967
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
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
)ORZVROYHU 7KH LQKRXVH IORZ VROYHU Tenasi +\DPV HW DO ZDV XVHG LQ WKLV VWXG\ WR VLPXODWH ERWK LQVSLUDWLRQH[SLUDWLRQDQGDIXOOUHVSLUDWRU\F\FOH7KHEDVHOLQHIORZVROYHULQTenasiHPSOR\VDQRGH FHQWHUHG ILQLWH YROXPH LPSOLFLW VFKHPH ZLWK KLJK UHVROXWLRQ IOX[HV EDVHG RQ 5RH DYHUDJLQJ DQG D 1HZWRQ VXELWHUDWLRQ SURFHGXUH IRU WLPH DFFXUDF\ 7KH OLQHDU V\VWHP DW HDFK 1HZWRQ VXELWHUDWLRQ LV VROYHGXVLQJD6\PPHWULF*DXVV±6HLGHODOJRULWKP)RUWKHFDVHVFRQVLGHUHGKHUHTenasi VROYHVWKH DUWLILFLDOFRPSUHVVLELOLW\ IRUP RI WKH LQFRPSUHVVLEOH 1DYLHU6WRNHV HTXDWLRQV Tenasi KDV EHHQ YDOLGDWHGLQDSUHYLRXVVWXG\IRUVWHDG\DQGXQVWHDG\IORZWKURXJKLGHDOL]HGDQG&7EDVHGJHRPHWULHV *UXHW]HPDFKHU 7KH FDVHV SUHVHQWHG KHUH DUH VROYHG XVLQJ D /DUJH (GG\ 6LPXODWLRQ /(6 IRUPXODWLRQZLWKWKH:DOO$GDSWLQJ/RFDO(GG\YLVFRVLW\ :$/( PRGHO 'XFURVHWDO EHLQJ XVHGIRUWKHVXEJULGVWUHVVHV
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ο 7DEOHVXPPDUL]HV WKH YDULRXV SDUDPHWHUV WKDW ZHUH XVHG LQ WKHVH VLPXODWLRQV 7KH :RPHUVOH\ QXPEHU :RPHUVOH\ VKRZQ LQ WKH WDEOH LV WKH UDWLR RI WKH WUDQVLHQW LQHUWLDO IRUFH WR WKH YLVFRXV IRUFH DQG LV D VLJQLILFDQW QRQGLPHQVLRQDO SDUDPHWHU LQ WKH VWXG\ RI WUDQVLHQW IORZV ,W LV GHILQHG DVȽ ൌ ඥɘΤɋ ZKHUH 5 LV WKH UDGLXV RI WKH WUDFKHDɋWKH NLQHPDWLF YLVFRVLW\ DQGɘ ൌ ʹɎᐦZKHUHᐦLV WKH EUHDWKLQJ UDWH 7KH 5H\QROGV QXPEHU LV GHILQHG DV ൌ ୫ୟ୶ ΤȤ ZKHUH ' LV WKH DYHUDJH GLDPHWHU RI WKH WUDFKHDDQG୫ୟ୶ LVODUJHVWRIWKHYHORFLWLHVLPSRVHGDWWKHGLVWDOERXQGDULHV 7KH FRQVWDQW LQVSLUDWLRQ DQG H[SLUDWLRQ VLPXODWLRQV FRUUHVSRQGHG WR WKH SHDN LQVSLUDWLRQ DQG H[SLUDWLRQ IRU WKH WZR EUHDWKLQJ UDWHV FRQVLGHUHG KHUH KHUHLQDIWHU UHIHUUHG WR DVȽ ൌ Ͳ 7KH\ ZHUH FDUULHGRXWIRULWHUDWLRQVDQGWKHUHVXOWLQJVROXWLRQVZHUHWLPHDYHUDJHGRYHUWKHODVWWLPH VWHSV 7DEOH 3DUDPHWHUVIRUWKHEUHDWKLQJF\FOHVFRQVLGHUHGLQWKLVVWXG\
%UHDWKLQJ5DWH EUHDWKVPLQXWH EUHDWKVPLQXWH
968
Ƚ
5H
ο VHFRQGV ͲǤͲͲͳͲͲͶͲͳͲͶ ͲǤͲͲͲͷͲʹͲͲͺͲ͵ʹ
7 VHFRQGV
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
%RXQGDU\FRQGLWLRQV +XPDQVKDYHWZROXQJVZKLFKFRQVLVWRIILYHOREHV7KUHHOREHVRQWKHULJKWDQGWZRRQWKHOHIW LHULJKWVXSHULRU 56 ULJKWPLGGOH 50 ULJKWLQIHULRU 5, OHIWVXSHULRU /6 DQGOHIWLQIHULRU /, EURQFKXV)RUWKHWUDQVLHQWEUHDWKLQJFDVHVDVLQXVRLGDOZDYHIRUPYHORFLW\SURILOHZDVLPSRVHGDWWKH ഥ୫ୟ୶ ො ሺɘሻ ൌ ഥ୫ୟ୶ ො ሺԄሻZKLOHWKHSUHVVXUHZDVDOORZHG ሬሬሬԦ୭୳୲ ൌ GLVWDOOREDUERXQGDULHVLH WR IORDW 7R HQIRUFH WKH DSSURSULDWH YHORFLWLHV DW OREDU ERXQGDULHV DQ H[SUHVVLRQ IRU YHORFLW\ DV D ഥ୫ୟ୶ ൌ ɘοɋ୪୭ୠୣ Τʹ୭୳୲ IXQFWLRQRIWKHOREDUYROXPHοɋ୪୭ୠୣ ZDVZULWWHQ *UXHW]HPDFKHU LH ZKHUH୭୳୲ LVDUHDDWWKHDSSURSULDWHGLVWDOERXQGDU\DQGοɋ୪୭ୠୣ LVDQG/ FRUUHVSRQGLQJWRWKH56505,/6DQG/,UHVSHFWLYHO\ +RUVILHOGHWDO 7KHYHORFLW\XVHG IRUWKHLQVSLUDWLRQH[SLUDWLRQFDVHVPDWFKHGWKHIORZFRQGLWLRQVDWSHDNLQVSLUDWLRQDQGH[SLUDWLRQRI WKHWUDQVLHQWEUHDWKLQJFDVHVLHDWSKDVHDQJOHRIɎȀʹDQG͵ɎȀʹUHVSHFWLYHO\$WWKHLQOHWERXQGDU\ D SXUH 'LULFKOHW ERXQGDU\ FRQGLWLRQ ZDV XVHG WR NHHS VWDWLF SUHVVXUH IL[HG DW VWDQGDUG DWPRVSKHULF SUHVVXUHZKLOHWKHYHORFLWLHVZHUHDOORZHGWRIORDW
5HVXOWVDQG'LVFXVVLRQ 6LPXODWLRQV ZHUH FDUULHG RXW IRU WKH HQWLUH DLUZD\ JHRPHWU\ LQ DGGLWLRQ WR WKH ORZHU DLUZD\V JHRPHWU\ )RU HDFK IORZ UDWH WZR VLPXODWLRQV FRQVWDQW LQVSLUDWLRQ DQG H[SLUDWLRQ DQG RQH IXOO EUHDWKLQJF\FOHVLPXODWLRQZHUHFDUULHGRXW7KLVUHVXOWHGLQVLPXODWLRQVSHUIORZUDWHDQGDWRWDORI VLPXODWLRQV7KHFRQVWDQWLQVSLUDWLRQH[SLUDWLRQFDVHVZHUHFRQGXFWHGDWWZR5H\QROGVQXPEHUV LHDQGDQDORJRXVWRSHDNIORZFRQGLWLRQVLQWKHIXOOEUHDWKLQJFDVHVLHWKH:RPHUVOH\ QXPEHUVRIDQGUHVSHFWLYHO\)LYHFURVVVHFWLRQVRILQWHUHVWLQWKHORZHUDLUZD\VVKRZQLQ )LJXUH ZHUH VHOHFWHG IRU DQDO\VLV 7KHVH FURVVVHFWLRQV DUH UHSUHVHQWDWLYH RI WKH DLUIORZ HQWHULQJ HDFKOREDUEURQFKXV9ROXPHWULFIOX[HVZHUHFRPSXWHGDWHDFKRIWKHFURVVVHFWLRQV7KHGHYLDWLRQRI IORZUDWHVIURPWKHWDUJHWHGYDOXHVZHUHIRXQGQRPRUHWKDQDQGLQORZHUDLUZD\VDQGWKH HQWLUHDLUZD\JHRPHWU\UHVSHFWLYHO\
)LJXUH )LYHFURVVVHFWLRQVH[DPLQHGIRUHDFKFDVHDWHDFKRIWKHOREDUEURQFKXV
969
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
,QVSLUDWLRQ 3HDNLQVSLUDWLRQLQEUHDWKLQJF\FOHVROXWLRQVRFFXUVDWDSKDVHDQJOHሺԄሻRIɎȀʹDWW VDQGW V IRUĮ ൌ ͶǤʹDQGȽ ൌ Ǥͺ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
)LJXUH 6DJLWWDOFURVVVHFWLRQRIWKH(7$LQFOXGLQJWUDFKHDVKRZLQJYHORFLW\PDJQLWXGHGXULQJLQVSLUDWLRQ
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
970
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
)LJXUH &URVVVHFWLRQDOFRURQDOSODQHRIWKHILUVWJHQHUDWLRQRISXOPRQDU\DLUZD\LOOXVWUDWLQJWXUEXOHQFH LQWHQVLW\IRUKLJKIORZUDWHGXULQJLQVSLUDWLRQ7KHHQWLUHDLUZD\DQGWKHORZHUDLUZD\JHRPHWU\RQWKHOHIWDQG ULJKWUHVSHFWLYHO\7KHYDOXHRIWXUEXOHQFHLQWHQVLW\OLPLWHGWR
6HFRQGDU\ IORZ YHORFLW\ YHFWRUV FRORUHG E\ YHORFLW\ PDJQLWXGH DUH VKRZQ DW YDULRXV FURVV VHFWLRQV GHSLFWHGLQ)LJXUH LQ)LJXUH7KHUHVXOWVVKRZQKHUHLQFOXGHWKDWREWDLQHGIRUWKHHQWLUH DLUZD\JHRPHWU\DVZHOODVWKHORZHUDLUZD\VJHRPHWU\,QWKLVILJXUHRQO\WKHKLJKIORZUDWHUHVXOWV DUH VKRZQ 7KLV LV VWULFWO\ GXH WR WKH SDJH QXPEHU OLPLWDWLRQ WKRXJK WKH TXDOLWDWLYH QDWXUH RI WKH FRPSDULVRQLVVLPLODUEHWZHHQWKHKLJKDQGORZIORZUDWHFDVHV $V FDQ EH VHHQ IURP )LJXUH FOHDU GLIIHUHQFHV DUH YLVLEOH LQ WKH FURVVIORZ YHORFLW\ YHFWRU SDWWHUQVIRUWKH5650DQGWKH/,EURQFKLZKLOHWKHGLIIHUHQFHVDUHOHVVSURQRXQFHGIRUWKHRWKHU WZR ORFDWLRQV +RZHYHU GLIIHUHQFHV LQ YHORFLW\ PDJQLWXGH WKH FRORUV LQ )LJXUH FDQ EH VHHQ DW WKHVH WZR ORFDWLRQV 5, DQG /6 ,Q WKH 56 WKH GLIIHUHQFHV EHWZHHQ WKH WZR WUDQVLHQW EUHDWKLQJ VROXWLRQVDUHTXLWHFOHDU7KHWUDQVLHQWEUHDWKLQJHQWLUHDLUZD\JHRPHWU\VROXWLRQVKRZVWKHSUHVHQFH RI WZR GLVWLQFW YRUWLFHV ZKLOH WKH FRUUHVSRQGLQJ ORZHU DLUZD\V VROXWLRQ KDV WKUHH ZHOO GHILQHG YRUWLFHV 7KH GLIIHUHQFHV EHWZHHQ WKH WLPHDYHUDJHG VROXWLRQV DUH HYHQ PRUH SURQRXQFHG ZLWK WKH HQWLUHDLUZD\JHRPHWU\VKRZLQJWKHSUHVHQFHRIDVLQJOHYRUWH[ZKLOHWZRZHOOGHILQHGYRUWLFHVFDQ EH VHHQ LQ WKH ORZHU DLUZD\V VROXWLRQ $QRWKHU FRPSDULVRQ WKDW FDQ EH PDGH LV EHWZHHQ WKH WLPH DYHUDJHGDQGWUDQVLHQWEUHDWKLQJVROXWLRQV&RPSDULQJWKHVHIRUWKHHQWLUHDLUZD\JHRPHWU\RQHFDQ VHHWKDWWKHUHDUHWZRYRUWLFHVIRUWKHWUDQVLHQWEUHDWKLQJFDVHZKLOHWKHUHLVDVLQJOHYRUWH[IRUWKH WLPHDYHUDJHGFDVH7KHSUHVHQFHRIWKHVHFRQGYRUWH[WRZDUGVWKHERWWRPRIWKHFURVVVHFWLRQSXVKHV WKHRWKHUYRUWH[DJDLQVWWKHHGJHVRIWKHFURVVVHFWLRQHIIHFWLYHO\VTXLVKLQJLW7KLVDOVROHDGVWRWKH SUHVHQFHRIDKLJKHUYHORFLW\UHJLRQGRZQWKHOHIWVLGHRIWKHFURVVVHFWLRQWKDWLVDEVHQWLQWKHIXOO EUHDWKLQJ F\FOH FDVH 6LPLODU GLIIHUHQFHV FDQ EH REVHUYHG E\ FRPSDULQJ WKH WLPHDYHUDJHG DQG WUDQVLHQWEUHDWKLQJVROXWLRQVIRUWKHORZHUDLUZD\VRQO\7KHGLIIHUHQFHVLQWKHVHFRQGDU\IORZIRUWKH 50 DUH PRUH SURQRXQFHG FRPSDUHG WR WKH 56 EURQFKXV 6LPLODU WRWKH 56 WKH QXPEHU RI YRUWLFHV SUHVHQW VHHPV WR JR XS E\ RQH ZKHQ FRPSDULQJ WKH FRUUHVSRQGLQJ WLPHDYHUDJHG DQG WUDQVLHQW EUHDWKLQJVROXWLRQV7KHWLPHDYHUDJHGORZHUDLUZD\VVROXWLRQKDVDFORYHUOHDIOLNHSDWWHUQZLWKWKH IRXUWK YRUWH[ EHLQJ IDLUO\ ZHDN $ FRPSDULVRQ RI WKH IXOO EUHDWKLQJ F\FOH VROXWLRQV IRU WKH HQWLUH 971
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
DLUZD\JHRPHWU\ZLWKWKHORZHUDLUZD\VRQO\FDVHLQGLFDWHVWKHSUHVHQFHRIDYRUWH[WRZDUGVWKHWRS RIWKHFURVVVHFWLRQ IRUWKHORZHUFDVH ZKLFKLVFOHDUO\PLVVLQJIURPWKHHQWLUHDLUZD\JHRPHWU\
)LJXUH 6HFRQGDU\IORZVGXULQJLQVSLUDWLRQIRUWKHHQWLUHDQGWKHORZHUDLUZD\JHRPHWU\
2QO\VXEWOHGLIIHUHQFHVDUHYLVLEOHLQWKHFURVVIORZYHORFLW\YHFWRUSDWWHUQVEHWZHHQWKHVROXWLRQV IRUWKH5,/6DQG/,EURQFKL'LIIHUHQFHVDUHSUHVHQWLQWKHYHORFLW\PDJQLWXGHDWDOOWKHVHVWDWLRQV $ SRVVLEOH H[SODQDWLRQ IRU WKHVH GLIIHUHQFHV FRXOG EH WKH GLVWDQFH WR WKHVH FURVVVHFWLRQV IURP WKH HQWUDQFHWRWKHWUDFKHDLHWKHIDUWKHU\RXJHWDZD\IURPWKHH[LWRIWKH(7$WKHOHVVHULWVHIIHFWZLOO EH7KLVLVEHFDXVHWKHORZ5H\QROGVQXPEHURIWKHIORZVWKURXJKWKHORZHUDLUZD\VZKLFKWHQGVWR GDPSRXWPRVWRIWKHWXUEXOHQWFRQWHQWZLWKLQFUHDVLQJUHVLGHQFHWLPH
972
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
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
)LJXUH 6HFRQGDU\IORZVGXULQJH[SLUDWLRQIRUHQWLUHDQGWKHORZHUDLUZD\JHRPHWU\
973
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
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
)LJXUH &URVVVHFWLRQDOFRURQDOSODQHRIWKHILUVWJHQHUDWLRQRISXOPRQDU\DLUZD\LOOXVWUDWLQJWXUEXOHQFH LQWHQVLW\IRUKLJKIORZUDWHGXULQJH[SLUDWLRQ7KHHQWLUHDLUZD\DQGWKHORZHUDLUZD\JHRPHWU\RQWKHOHIWDQG ULJKWUHVSHFWLYHO\7KHYDOXHRIWXUEXOHQFHLQWHQVLW\OLPLWHGWR
,WFDQEHVHHQIURP)LJXUHWKDWWKHWXUEXOHQFHLQWHQVLWLHVDUHGURSSLQJQHDUWKHWUDFKHD7KLVLV FRQVLVWHQW ZLWK ZKDW LV VHHQ LQ )LJXUH ZKLFK VKRZV D YLVXDOL]DWLRQ RI WKH WXUEXOHQW VWUXFWXUHV SUHVHQWLQWKH(7$DVWKHWXUEXOHQWVWUXFWXUHVDUHPRVWO\DEVHQWLQWKHUHJLRQRIWKHWKRUD[+RZHYHU RQFH WKH IORZ SDVVHV WKH JORWWLV VLJQLILFDQW WXUEXOHQW VWUXFWXUHV DSSHDU 7KLV LV QRW VXUSULVLQJ JLYHQ WKDWLWLVWKHJORWWLVZKLFKFDXVHVWKHODU\QJHDOMHWWRIRUPGXULQJLQVSLUDWLRQDQGWKHVDPHJHRPHWU\ UHVXOWVLQWXUEXOHQFHEHLQJJHQHUDWHGGXULQJH[SLUDWLRQ
974
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
7KH FKDQJHV LQ WKH YHORFLW\ IORZ ILHOG REVHUYHG LQ )LJXUH DQG WKH WXUEXOHQFH JHQHUDWHG LQ WKH (7$ GXULQJ H[SLUDWLRQ FRXOG LQIOXHQFH SDUWLFOH GHSRVLWLRQ SDWWHUQV DV RQH JRHV WKURXJK D EUHDWKLQJ F\FOH 3DUWLFOH LQVSLUDWLRQ DQG GHSRVLWLRQ ZDV QRW FDUULHG RXW DV SDUW RI WKLV UHVHDUFK LW LV KRZHYHU SODQQHGDVDFRQWLQXDWLRQ
)LJXUH ,VRVXUIDFHRI4FULWHULRQFRORUHGE\YHORFLW\PDJQLWXGHIRUȽ ൌ Ǥͺ%HKLQGYLHZVDJLWWDOYLHZ DQGULJKWREOLTXH ι RIWKH(7$IURPOHIWWRULJKW7KHJHRPHWU\LVLQJUH\
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
5HIHUHQFHV $OZDQ$5RVV$5HVQLNRII60HQGLV6&UX]$$DQG0LQHOOL( Global Alliance Against Chronic Respiratory Diseases )URP :RUOG +HDOWK 2UJDQL]DWLRQ :+2 KWWS ZZZZKRLQWJDUGSXEOLFDWLRQV*$5'BDFWLRQSODQB),1$/SGI %DOO&*8GGLQ0 3ROODUG$ D +LJKUHVROXWLRQWXUEXOHQFHPRGHOOLQJRIDLUIORZLQDQ LGHDOLVHGKXPDQH[WUDWKRUDFLFDLUZD\Computers & Fluids %DOO&*8GGLQ0 3ROODUG$ E 0HDQIORZVWUXFWXUHVLQVLGHWKHKXPDQXSSHUDLUZD\ )ORZTurbulence and Combustion 975
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
'H %DFNHU - : 9RV : * *RUOH & ' *HUPRQSUp 3 3DUWRHQV % :X\WV ) / 'H %DFNHU : )ORZ DQDO\VHV LQ WKH ORZHU DLUZD\V SDWLHQWVSHFLILF PRGHO DQG ERXQGDU\ FRQGLWLRQVMedical engineering & physics 'XFURV ) 1LFRXG ) 3RLQVRW 7 :DOODGDSWLQJ ORFDO HGG\YLVFRVLW\ PRGHOV IRU VLPXODWLRQVLQFRPSOH[JHRPHWULHVInternational Conference on Computational Conference SS SS *RQGD, 7DUJHWLQJE\GHSRVLWLRQDrugs and the pharmaceutical sciences *UXHW]HPDFKHU 5 5 Numerical simulation of human breathing and particle transport through a CT-based pulmonary airway geometry. &KDWWDQRRJD 7KH 8QLYHUVLW\ RI 7HQQHVVHH DW &KDWWDQRRJD&KDWWDQRRJD +HHQDQ $) 0DWLGD ( 3ROODUG $ )LQOD\ :+ ([SHULPHQWDO PHDVXUHPHQWV DQG FRPSXWDWLRQDO PRGHOLQJ RI WKH IORZ ILHOG LQ DQ LGHDOL]HGKXPDQ RURSKDU\Q[ Experiments in Fluids ± +RUVILHOG.'DUW*2OVRQ'()LOOH\*) &XPPLQJ* 0RGHOVRIWKHKXPDQ EURQFKLDOWUHHJournal of applied physiology +\DPV ' * 6UHHQLYDV . 3DQNDMDNVKDQ 5 1LFKROV ' 6 %ULOH\ : 5 :KLWILHOG ' / &RPSXWDWLRQDO VLPXODWLRQ RI PRGHO DQG IXOO VFDOH &ODVV WUXFNV ZLWK GUDJ UHGXFWLRQ GHYLFHVComputers & Fluids -RKQVWRQH$8GGLQ03ROODUG$+HHQDQ$)LQOD\:+ 7KHIORZLQVLGHDQLGHDOLVHGIRUP RIWKHKXPDQH[WUDWKRUDFLFDLUZD\Experiments in Fluids .OHLQVWUHXHU& =KDQJ= $LUIORZDQGSDUWLFOHWUDQVSRUWLQWKHKXPDQUHVSLUDWRU\V\VWHP Annual Review of Fluid Mechanics /LQ&/7DZKDL0+0F/HQQDQ* +RIIPDQ($ &KDUDFWHULVWLFVRIWKHWXUEXOHQW ODU\QJHDOMHWDQGLWVHIIHFWRQDLUIORZLQWKHKXPDQLQWUDWKRUDFLFDLUZD\VRespiratory physiology & neurobiology 6WDSOHWRQ.:*XHQWVFK(+RVNLQVRQ0.)LQOD\:+ 2QWKHVXLWDELOLW\RIN±HWXUEXOHQFH PRGHOLQJIRUDHURVROGHSRVLWLRQLQWKHPRXWKDQGWKURDW DFRPSDULVRQZLWKH[SHULPHQWJ Aerosol Sci ± T-Rex: Automated Boundary Layer Meshing 5HWULHYHG IURP 3RLQWZLVH KWWS ZZZSRLQWZLVHFRPIRFXV)RFXV2QB75H[SGI :HLEHO ( 5 Geometry and dimensions of airways of conductive and transitory zones. 6SULQJHU%HUOLQ+HLGHOEHUJ :RPHUVOH\ - 5 0HWKRG IRU WKH FDOFXODWLRQ RI YHORFLW\ UDWH RI IORZ DQG YLVFRXV GUDJ LQ DUWHULHVZKHQWKHSUHVVXUHJUDGLHQWLVNQRZQThe Journal of physiology, ;X&6LQ60F'RQRXJK-08GXSD-.*XH]$$UHQV5 :RRWWRQ'0 &RPSXWDWLRQDO IOXLG G\QDPLFV PRGHOLQJ RI WKH XSSHU DLUZD\ RI FKLOGUHQ ZLWK REVWUXFWLYH VOHHS DSQHDV\QGURPHLQVWHDG\IORZJournal of biomechanics
976
&)'LQYHVWLJDWLRQRIKXPDQWLGDOEUHDWKLQJWKURXJK KXPDQDLUZD\JHRPHWU\ -DPDVS$]DUQRRVK.LGDPEL6UHHQLYDVDQG$EGROODK$UDEVKDKL The University of Tennessee at Chattanooga, Chattanooga, TN, USA [email protected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eywords:+XPDQDLUZD\V&)',QVSLUDWLRQ([SLUDWLRQ7UDQVLHQWEUHDWKLQJ
,QWURGXFWLRQ 7KHUHDUHKXQGUHGVRIPLOOLRQVRISHRSOHZRUOGZLGHZKRVXIIHUIURPFKURQLFUHVSLUDWRU\GLVHDVHV VXFK DV DVWKPD DQG FKURQLF REVWUXFWLYH SXOPRQDU\ GLVRUGHU &23' REVWUXFWLYH VOHHS DSQHD V\QGURPH 26$6 SXOPRQDU\ K\SHUWHQVLRQ HWF $OZDQ $ HW DO $LU SROOXWLRQ LV GLUHFWO\ FRQQHFWHG WR WKHVH LOOQHVVHV EHFDXVH RI WKHGHSRVLWLRQRI SDUWLFXODWH SROOXWDQWV LQ WKH OXQJV 7KHVH WR[LF SROOXWDQW SDUWLFOHV KDYH WKH SRWHQWLDO WR LQGXFH WKHVH GLVHDVHV 3DUWLFOH GHSRVLWLRQ LV
Selection and peer-review under responsibility of the Scientific Programme Committee of ICCS 2016 c The Authors. Published by Elsevier B.V.
doi:10.1016/j.procs.2016.05.392
965
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
PDLQO\DIIHFWHGE\WKHIORZILHOGZLWKLQWKHUHVSLUDWRU\V\VWHP7KHVHHIIHFWVDUHYHU\SURPLQHQWLQ WKHH[WUDWKRUDFLFDLUZD\ (7$ $QLQYHVWLJDWLRQUHSRUWHGWKDW±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
966
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
JHRPHWULHVXWLOL]HGLQPRVWRIWKHVHVWXGLHVZHUHOLPLWHGWRHLWKHUWKH(7$RUWKHORZHUDLUZD\RQO\ )RULQVWDQFH =KDQJ= .OHLQVWUHXHU& FRPSDUHGERWKWKHSHDNLQVSLUDWLRQDQGH[SLUDWLRQ YHORFLW\ SURILOHV IRU WKH :RPHUVOH\ QXPEHU Ƚ DQG IRXQG JRRG DJUHHPHQW ZLWK WKRVH RI LQVWDQWDQHRXVO\HTXLYDOHQWFRQVWDQWLQVSLUDWLRQH[SLUDWLRQFDVHV7KLVSDSHUIRFXVHVRQWKHHIIHFWVRI WKH(7$RQWKHORZHUDLUZD\ DQGYLFHYHUVD IRUDIXOOEUHDWKLQJF\FOHDQGFRPSDUHVWKHUHVXOWVRI WUDQVLHQW VLPXODWLRQV ZLWK VLPXODWLRQV FRUUHVSRQGLQJ WR FRQVWDQW LQVSLUDWLRQ DQG H[SLUDWLRQ 7R WKH EHVWRIWKHDXWKRUV¶NQRZOHGJHWKHVHFRPSDULVRQVKDYHQRWEHHQFDUULHGRXWE\DQ\UHVHDUFKHUIRU WKHHQWLUH FRPELQHG(7$ORZHU JHRPHWU\
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
)LJXUH D 7KH&7EDVHGORZHUDLUZD\JHRPHWU\EDQGF 7KHHQWLUHDLUZD\JHRPHWU\
%RWK JHRPHWULHV ZHUH PHVKHG XVLQJ 3RLQWZLVH YHUVLRQ 7KH VXUIDFH PHVK ZDV HQWLUHO\ VWUXFWXUHGDVWKLVKHOSHGUHGXFHWKHQXPEHURIVXUIDFHQRGHVFRPSDUHGWRXWLOL]LQJDQXQVWUXFWXUHG 967
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
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
)ORZVROYHU 7KH LQKRXVH IORZ VROYHU Tenasi +\DPV HW DO ZDV XVHG LQ WKLV VWXG\ WR VLPXODWH ERWK LQVSLUDWLRQH[SLUDWLRQDQGDIXOOUHVSLUDWRU\F\FOH7KHEDVHOLQHIORZVROYHULQTenasiHPSOR\VDQRGH FHQWHUHG ILQLWH YROXPH LPSOLFLW VFKHPH ZLWK KLJK UHVROXWLRQ IOX[HV EDVHG RQ 5RH DYHUDJLQJ DQG D 1HZWRQ VXELWHUDWLRQ SURFHGXUH IRU WLPH DFFXUDF\ 7KH OLQHDU V\VWHP DW HDFK 1HZWRQ VXELWHUDWLRQ LV VROYHGXVLQJD6\PPHWULF*DXVV±6HLGHODOJRULWKP)RUWKHFDVHVFRQVLGHUHGKHUHTenasi VROYHVWKH DUWLILFLDOFRPSUHVVLELOLW\ IRUP RI WKH LQFRPSUHVVLEOH 1DYLHU6WRNHV HTXDWLRQV Tenasi KDV EHHQ YDOLGDWHGLQDSUHYLRXVVWXG\IRUVWHDG\DQGXQVWHDG\IORZWKURXJKLGHDOL]HGDQG&7EDVHGJHRPHWULHV *UXHW]HPDFKHU 7KH FDVHV SUHVHQWHG KHUH DUH VROYHG XVLQJ D /DUJH (GG\ 6LPXODWLRQ /(6 IRUPXODWLRQZLWKWKH:DOO$GDSWLQJ/RFDO(GG\YLVFRVLW\ :$/( PRGHO 'XFURVHWDO EHLQJ XVHGIRUWKHVXEJULGVWUHVVHV
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ο 7DEOHVXPPDUL]HV WKH YDULRXV SDUDPHWHUV WKDW ZHUH XVHG LQ WKHVH VLPXODWLRQV 7KH :RPHUVOH\ QXPEHU :RPHUVOH\ VKRZQ LQ WKH WDEOH LV WKH UDWLR RI WKH WUDQVLHQW LQHUWLDO IRUFH WR WKH YLVFRXV IRUFH DQG LV D VLJQLILFDQW QRQGLPHQVLRQDO SDUDPHWHU LQ WKH VWXG\ RI WUDQVLHQW IORZV ,W LV GHILQHG DVȽ ൌ ඥɘΤɋ ZKHUH 5 LV WKH UDGLXV RI WKH WUDFKHDɋWKH NLQHPDWLF YLVFRVLW\ DQGɘ ൌ ʹɎᐦZKHUHᐦLV WKH EUHDWKLQJ UDWH 7KH 5H\QROGV QXPEHU LV GHILQHG DV ൌ ୫ୟ୶ ΤȤ ZKHUH ' LV WKH DYHUDJH GLDPHWHU RI WKH WUDFKHDDQG୫ୟ୶ LVODUJHVWRIWKHYHORFLWLHVLPSRVHGDWWKHGLVWDOERXQGDULHV 7KH FRQVWDQW LQVSLUDWLRQ DQG H[SLUDWLRQ VLPXODWLRQV FRUUHVSRQGHG WR WKH SHDN LQVSLUDWLRQ DQG H[SLUDWLRQ IRU WKH WZR EUHDWKLQJ UDWHV FRQVLGHUHG KHUH KHUHLQDIWHU UHIHUUHG WR DVȽ ൌ Ͳ 7KH\ ZHUH FDUULHGRXWIRULWHUDWLRQVDQGWKHUHVXOWLQJVROXWLRQVZHUHWLPHDYHUDJHGRYHUWKHODVWWLPH VWHSV 7DEOH 3DUDPHWHUVIRUWKHEUHDWKLQJF\FOHVFRQVLGHUHGLQWKLVVWXG\
%UHDWKLQJ5DWH EUHDWKVPLQXWH EUHDWKVPLQXWH
968
Ƚ
5H
ο VHFRQGV ͲǤͲͲͳͲͲͶͲͳͲͶ ͲǤͲͲͲͷͲʹͲͲͺͲ͵ʹ
7 VHFRQGV
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
%RXQGDU\FRQGLWLRQV +XPDQVKDYHWZROXQJVZKLFKFRQVLVWRIILYHOREHV7KUHHOREHVRQWKHULJKWDQGWZRRQWKHOHIW LHULJKWVXSHULRU 56 ULJKWPLGGOH 50 ULJKWLQIHULRU 5, OHIWVXSHULRU /6 DQGOHIWLQIHULRU /, EURQFKXV)RUWKHWUDQVLHQWEUHDWKLQJFDVHVDVLQXVRLGDOZDYHIRUPYHORFLW\SURILOHZDVLPSRVHGDWWKH ഥ୫ୟ୶ ො ሺɘሻ ൌ ഥ୫ୟ୶ ො ሺԄሻZKLOHWKHSUHVVXUHZDVDOORZHG ሬሬሬԦ୭୳୲ ൌ GLVWDOOREDUERXQGDULHVLH WR IORDW 7R HQIRUFH WKH DSSURSULDWH YHORFLWLHV DW OREDU ERXQGDULHV DQ H[SUHVVLRQ IRU YHORFLW\ DV D ഥ୫ୟ୶ ൌ ɘοɋ୪୭ୠୣ Τʹ୭୳୲ IXQFWLRQRIWKHOREDUYROXPHοɋ୪୭ୠୣ ZDVZULWWHQ *UXHW]HPDFKHU LH ZKHUH୭୳୲ LVDUHDDWWKHDSSURSULDWHGLVWDOERXQGDU\DQGοɋ୪୭ୠୣ LVDQG/ FRUUHVSRQGLQJWRWKH56505,/6DQG/,UHVSHFWLYHO\ +RUVILHOGHWDO 7KHYHORFLW\XVHG IRUWKHLQVSLUDWLRQH[SLUDWLRQFDVHVPDWFKHGWKHIORZFRQGLWLRQVDWSHDNLQVSLUDWLRQDQGH[SLUDWLRQRI WKHWUDQVLHQWEUHDWKLQJFDVHVLHDWSKDVHDQJOHRIɎȀʹDQG͵ɎȀʹUHVSHFWLYHO\$WWKHLQOHWERXQGDU\ D SXUH 'LULFKOHW ERXQGDU\ FRQGLWLRQ ZDV XVHG WR NHHS VWDWLF SUHVVXUH IL[HG DW VWDQGDUG DWPRVSKHULF SUHVVXUHZKLOHWKHYHORFLWLHVZHUHDOORZHGWRIORDW
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
)LJXUH )LYHFURVVVHFWLRQVH[DPLQHGIRUHDFKFDVHDWHDFKRIWKHOREDUEURQFKXV
969
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
,QVSLUDWLRQ 3HDNLQVSLUDWLRQLQEUHDWKLQJF\FOHVROXWLRQVRFFXUVDWDSKDVHDQJOHሺԄሻRIɎȀʹDWW VDQGW V IRUĮ ൌ ͶǤʹDQGȽ ൌ Ǥͺ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
)LJXUH 6DJLWWDOFURVVVHFWLRQRIWKH(7$LQFOXGLQJWUDFKHDVKRZLQJYHORFLW\PDJQLWXGHGXULQJLQVSLUDWLRQ
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
970
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
)LJXUH &URVVVHFWLRQDOFRURQDOSODQHRIWKHILUVWJHQHUDWLRQRISXOPRQDU\DLUZD\LOOXVWUDWLQJWXUEXOHQFH LQWHQVLW\IRUKLJKIORZUDWHGXULQJLQVSLUDWLRQ7KHHQWLUHDLUZD\DQGWKHORZHUDLUZD\JHRPHWU\RQWKHOHIWDQG ULJKWUHVSHFWLYHO\7KHYDOXHRIWXUEXOHQFHLQWHQVLW\OLPLWHGWR
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
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
DLUZD\JHRPHWU\ZLWKWKHORZHUDLUZD\VRQO\FDVHLQGLFDWHVWKHSUHVHQFHRIDYRUWH[WRZDUGVWKHWRS RIWKHFURVVVHFWLRQ IRUWKHORZHUFDVH ZKLFKLVFOHDUO\PLVVLQJIURPWKHHQWLUHDLUZD\JHRPHWU\
)LJXUH 6HFRQGDU\IORZVGXULQJLQVSLUDWLRQIRUWKHHQWLUHDQGWKHORZHUDLUZD\JHRPHWU\
2QO\VXEWOHGLIIHUHQFHVDUHYLVLEOHLQWKHFURVVIORZYHORFLW\YHFWRUSDWWHUQVEHWZHHQWKHVROXWLRQV IRUWKH5,/6DQG/,EURQFKL'LIIHUHQFHVDUHSUHVHQWLQWKHYHORFLW\PDJQLWXGHDWDOOWKHVHVWDWLRQV $ SRVVLEOH H[SODQDWLRQ IRU WKHVH GLIIHUHQFHV FRXOG EH WKH GLVWDQFH WR WKHVH FURVVVHFWLRQV IURP WKH HQWUDQFHWRWKHWUDFKHDLHWKHIDUWKHU\RXJHWDZD\IURPWKHH[LWRIWKH(7$WKHOHVVHULWVHIIHFWZLOO EH7KLVLVEHFDXVHWKHORZ5H\QROGVQXPEHURIWKHIORZVWKURXJKWKHORZHUDLUZD\VZKLFKWHQGVWR GDPSRXWPRVWRIWKHWXUEXOHQWFRQWHQWZLWKLQFUHDVLQJUHVLGHQFHWLPH
972
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
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
)LJXUH 6HFRQGDU\IORZVGXULQJH[SLUDWLRQIRUHQWLUHDQGWKHORZHUDLUZD\JHRPHWU\
973
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
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
)LJXUH &URVVVHFWLRQDOFRURQDOSODQHRIWKHILUVWJHQHUDWLRQRISXOPRQDU\DLUZD\LOOXVWUDWLQJWXUEXOHQFH LQWHQVLW\IRUKLJKIORZUDWHGXULQJH[SLUDWLRQ7KHHQWLUHDLUZD\DQGWKHORZHUDLUZD\JHRPHWU\RQWKHOHIWDQG ULJKWUHVSHFWLYHO\7KHYDOXHRIWXUEXOHQFHLQWHQVLW\OLPLWHGWR
,WFDQEHVHHQIURP)LJXUHWKDWWKHWXUEXOHQFHLQWHQVLWLHVDUHGURSSLQJQHDUWKHWUDFKHD7KLVLV FRQVLVWHQW ZLWK ZKDW LV VHHQ LQ )LJXUH ZKLFK VKRZV D YLVXDOL]DWLRQ RI WKH WXUEXOHQW VWUXFWXUHV SUHVHQWLQWKH(7$DVWKHWXUEXOHQWVWUXFWXUHVDUHPRVWO\DEVHQWLQWKHUHJLRQRIWKHWKRUD[+RZHYHU RQFH WKH IORZ SDVVHV WKH JORWWLV VLJQLILFDQW WXUEXOHQW VWUXFWXUHV DSSHDU 7KLV LV QRW VXUSULVLQJ JLYHQ WKDWLWLVWKHJORWWLVZKLFKFDXVHVWKHODU\QJHDOMHWWRIRUPGXULQJLQVSLUDWLRQDQGWKHVDPHJHRPHWU\ UHVXOWVLQWXUEXOHQFHEHLQJJHQHUDWHGGXULQJH[SLUDWLRQ
974
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
7KH FKDQJHV LQ WKH YHORFLW\ IORZ ILHOG REVHUYHG LQ )LJXUH DQG WKH WXUEXOHQFH JHQHUDWHG LQ WKH (7$ GXULQJ H[SLUDWLRQ FRXOG LQIOXHQFH SDUWLFOH GHSRVLWLRQ SDWWHUQV DV RQH JRHV WKURXJK D EUHDWKLQJ F\FOH 3DUWLFOH LQVSLUDWLRQ DQG GHSRVLWLRQ ZDV QRW FDUULHG RXW DV SDUW RI WKLV UHVHDUFK LW LV KRZHYHU SODQQHGDVDFRQWLQXDWLRQ
)LJXUH ,VRVXUIDFHRI4FULWHULRQFRORUHGE\YHORFLW\PDJQLWXGHIRUȽ ൌ Ǥͺ%HKLQGYLHZVDJLWWDOYLHZ DQGULJKWREOLTXH ι RIWKH(7$IURPOHIWWRULJKW7KHJHRPHWU\LVLQJUH\
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
5HIHUHQFHV $OZDQ$5RVV$5HVQLNRII60HQGLV6&UX]$$DQG0LQHOOL( Global Alliance Against Chronic Respiratory Diseases )URP :RUOG +HDOWK 2UJDQL]DWLRQ :+2 KWWS ZZZZKRLQWJDUGSXEOLFDWLRQV*$5'BDFWLRQSODQB),1$/SGI %DOO&*8GGLQ0 3ROODUG$ D +LJKUHVROXWLRQWXUEXOHQFHPRGHOOLQJRIDLUIORZLQDQ LGHDOLVHGKXPDQH[WUDWKRUDFLFDLUZD\Computers & Fluids %DOO&*8GGLQ0 3ROODUG$ E 0HDQIORZVWUXFWXUHVLQVLGHWKHKXPDQXSSHUDLUZD\ )ORZTurbulence and Combustion 975
CFD investigation of human tidal breathing through human airway geometry
Azarnoosh et al.
'H %DFNHU - : 9RV : * *RUOH & ' *HUPRQSUp 3 3DUWRHQV % :X\WV ) / 'H %DFNHU : )ORZ DQDO\VHV LQ WKH ORZHU DLUZD\V SDWLHQWVSHFLILF PRGHO DQG ERXQGDU\ FRQGLWLRQVMedical engineering & physics 'XFURV ) 1LFRXG ) 3RLQVRW 7 :DOODGDSWLQJ ORFDO HGG\YLVFRVLW\ PRGHOV IRU VLPXODWLRQVLQFRPSOH[JHRPHWULHVInternational Conference on Computational Conference SS SS *RQGD, 7DUJHWLQJE\GHSRVLWLRQDrugs and the pharmaceutical sciences *UXHW]HPDFKHU 5 5 Numerical simulation of human breathing and particle transport through a CT-based pulmonary airway geometry. &KDWWDQRRJD 7KH 8QLYHUVLW\ RI 7HQQHVVHH DW &KDWWDQRRJD&KDWWDQRRJD +HHQDQ $) 0DWLGD ( 3ROODUG $ )LQOD\ :+ ([SHULPHQWDO PHDVXUHPHQWV DQG FRPSXWDWLRQDO PRGHOLQJ RI WKH IORZ ILHOG LQ DQ LGHDOL]HGKXPDQ RURSKDU\Q[ Experiments in Fluids ± +RUVILHOG.'DUW*2OVRQ'()LOOH\*) &XPPLQJ* 0RGHOVRIWKHKXPDQ EURQFKLDOWUHHJournal of applied physiology +\DPV ' * 6UHHQLYDV . 3DQNDMDNVKDQ 5 1LFKROV ' 6 %ULOH\ : 5 :KLWILHOG ' / &RPSXWDWLRQDO VLPXODWLRQ RI PRGHO DQG IXOO VFDOH &ODVV WUXFNV ZLWK GUDJ UHGXFWLRQ GHYLFHVComputers & Fluids -RKQVWRQH$8GGLQ03ROODUG$+HHQDQ$)LQOD\:+ 7KHIORZLQVLGHDQLGHDOLVHGIRUP RIWKHKXPDQH[WUDWKRUDFLFDLUZD\Experiments in Fluids .OHLQVWUHXHU& =KDQJ= $LUIORZDQGSDUWLFOHWUDQVSRUWLQWKHKXPDQUHVSLUDWRU\V\VWHP Annual Review of Fluid Mechanics /LQ&/7DZKDL0+0F/HQQDQ* +RIIPDQ($ &KDUDFWHULVWLFVRIWKHWXUEXOHQW ODU\QJHDOMHWDQGLWVHIIHFWRQDLUIORZLQWKHKXPDQLQWUDWKRUDFLFDLUZD\VRespiratory physiology & neurobiology 6WDSOHWRQ.:*XHQWVFK(+RVNLQVRQ0.)LQOD\:+ 2QWKHVXLWDELOLW\RIN±HWXUEXOHQFH PRGHOLQJIRUDHURVROGHSRVLWLRQLQWKHPRXWKDQGWKURDW DFRPSDULVRQZLWKH[SHULPHQWJ Aerosol Sci ± T-Rex: Automated Boundary Layer Meshing 5HWULHYHG IURP 3RLQWZLVH KWWS ZZZSRLQWZLVHFRPIRFXV)RFXV2QB75H[SGI :HLEHO ( 5 Geometry and dimensions of airways of conductive and transitory zones. 6SULQJHU%HUOLQ+HLGHOEHUJ :RPHUVOH\ - 5 0HWKRG IRU WKH FDOFXODWLRQ RI YHORFLW\ UDWH RI IORZ DQG YLVFRXV GUDJ LQ DUWHULHVZKHQWKHSUHVVXUHJUDGLHQWLVNQRZQThe Journal of physiology, ;X&6LQ60F'RQRXJK-08GXSD-.*XH]$$UHQV5 :RRWWRQ'0 &RPSXWDWLRQDO IOXLG G\QDPLFV PRGHOLQJ RI WKH XSSHU DLUZD\ RI FKLOGUHQ ZLWK REVWUXFWLYH VOHHS DSQHDV\QGURPHLQVWHDG\IORZJournal of biomechanics
976