Discovering lub Reynolds tooj

Cov neeg uas nyob deb ntawm physics, yog nplooj siab. Pib hauv cov ntawv nyeem txwv tsis pub kuv tsis tau, vim hais tias cov xov tooj ntawm Reynolds tus kheej kuv ho tsis ua kom muaj teb nyob rau hauv lub ib feem ntawm txoj kev paub ntawm qhov twg cia cov ntaub ntawv nyob rau hauv physics. Wb sim sau no kis.

Yuav kom sov ntxiv dab tsi Osborne Reynolds yog nyob rau hauv ib lub sij hawm nyob rau hauv lawv lub teb. Qhov no paub txog yog ib tug neeg sawv cev ntawm cov lus Askiv (ib txhia qhov chaw - Irish) scientific lub zej lub zos nyob rau hauv lub teb ntawm physics, engineering thiab hydraulics. Yug nyob rau hauv 1842, tom qab 28 xyoo, nws tau los ua ib tug xib fwb ntawm lub department ntawm cov yam ntxwv mechanics nyob rau hauv Cambridge. Nws kev tshawb fawb coj mus rau suav tus cwj pwm ntawm cov kua nyob rau hauv laminar (fawm kib) thiab turbulent (vortex) txaus. Tias nws yog tus faib ntawm ib tug zauv ntawm kev ib txoj kev hloov ntawm ib hom ntawm chav kawm mus rau lwm lub. Qhov no kom muaj nuj nqis yog lub npe hu rau peb raws li lub Reynolds tooj.

Yuav ua li cas yog lub ntsiab lus ntawm? Qhov no parameter yog tsis tas li thiab yog ib tug tej yam piv ntawm inertial rog thiab nrog kev sib txhuam nyob rau hauv lub kua ndlwg. Raws li xa mus rau lub kauj siv Re. Nrog hais txog cov chav nyob ntawm kev ntsuas, ces muaj yog tsis muaj leej twg, vim hais tias cov Reynolds tooj rau dej, gases thiab lwm yam nruab nrab yog ib tug dimensionless kom muaj nuj nqis (tooj per se).

Doubtless tsim nyog hwm perseverance English paub txog, uas yuav tsum tau siv ntau tshaj ib puas kev ntsuam xyuas kom paub tias xws li ib tug kev sib raug zoo. Nws muaj peev xwm kom paub tias cov nram qab no qauv: thaum muaj kev kub nqi (ntau tshaj 2 - 3 lab), cov dej ntws yog tag nrho turbulent, thiab rau me me - tag laminar.

Muaj ntau ntawm cov suav xa mus rau lub readings uas twb tau tsuas empirically, thiab hloov los yog infinite repetition yuav "poob tawm" ntawm tus ncej tam sim. Txawm li cas los, muaj ntau yam heev ntse txhais lawv los ntawm lub standpoint ntawm Newton kev cai. Nyob rau hauv tej yam yooj yim cov ntsiab lus, cov kua dej muaj ib tug tej yam inertia thiab nyhav kom muaj nws txav nyob rau tib lub ceev.

Qhov tseem ceeb ntawm no kauj, raws li cov ntaub ntawv los ntawm ntau qhov chaw, tsis tau overemphasized. Nws yog ib qhov muaj nuj nqis thiab txoj ntsiab cai ntawm nws cov qhia rau peb tias tej yam ntawm qhov chaw (dej, roj los yog lwm yam khoom) tsis yog li ntawd ntau npaum li cas nyob rau cov kev ceev, inertia thiab tsis sib haum xeeb, yuav ua li cas npaum li cas ntawm lawv kev sis raug zoo. Nws yog ib qhov kev sis raug zoo thiab yog reflected nyob rau hauv lub ratio, uas yog hu ua tus "Reynolds tus xov tooj". Rau dej, lub zog ntawm uas tshwm sim raws nqaim raws (los yog hlab), "Ntug" qhia yuav hloov tus nqi tshaj qhov taw qhia 12000 - 20000. Ib qho kev nce kuj ntawm lub nruab nrab yuav nce. Dej nyob rau hauv lub qhib qhov chaw thiab sab nraum daim duab yuav tsum inverted: ua Reynolds tooj tseem ceeb yuav txo tau cov kuj.
Nws siv ntawm no kauj yog tsis tsuas nyob rau hauv cov kua mechanics, tab sis kuj nyob rau hauv chaw ua dav hlua thiab shipbuilding. Piv txwv li, nws yog ib lub Reynolds tooj tso cai txhim khu kev qha tshuaj ntsuam txog ntawm tshiab aircraft qauv, siab me nyuam tiag tiag kev txiav txim ntawm cov huab cua khiav nyob rau hauv cov txo qauv.

PS nws tus kheej xam mis tsis coj nrog tib si: yog hais tias tus nyeem ntawv xav nyob rau hauv no lub npe, kawm qhov kev txiav txim ntawm xam ntawm xws magnitude yuav tsis tau yooj yim.