Kinematic vs Dynamic Viscosity
Dynamic viscosity thiab kinematic viscosity yog ob lub ntsiab lus tseem ceeb uas tau tham hauv cov dej dynamics. Ob lub tswv yim no muaj ntau yam kev siv hauv kev lag luam xws li dej dynamics, dej mechanics, aerodynamics, chemistry, thiab txawm tias kev kho mob science. Kev nkag siab zoo hauv cov ntsiab lus ntawm dynamic viscosity thiab kinematic viscosity yuav tsum tau ua kom zoo hauv cov haujlwm saum toj no. Hauv tsab xov xwm no, peb yuav tham txog dab tsi dynamic viscosity thiab kinematic viscosity yog, lawv cov ntsiab lus, kev siv ntawm dynamic thiab kinematic viscosity, qhov zoo sib xws thiab thaum kawg qhov sib txawv ntawm kinematic viscosity thiab dynamic viscosity.
Dynamic Viscosity yog dab tsi?
Txhawm rau nkag siab lub tswv yim ntawm dynamic viscosity, yuav tsum muaj lub tswv yim dav dav ntawm thaj chaw viscosity. Viscosity txhais tau tias yog ib qho kev ntsuas ntawm qhov tsis kam ntawm cov kua, uas yog deformed, los ntawm shear stress los yog tensile stress. Hauv ntau lo lus, viscosity yog "kev sib txhuam sab hauv" ntawm cov kua dej. Nws tseem hu ua lub thickness ntawm cov kua. Viscosity tsuas yog kev sib txhuam ntawm ob txheej ntawm cov kua dej thaum ob txheej txav mus rau ib leeg. Sir Isaac Newton yog ib tug pioneer hauv dej mechanics. Nws postulated tias, rau ib tug Newtonian kua, lub shear kev nyuaj siab ntawm cov khaubncaws sab nraud povtseg yog proportional rau lub ceev gradient nyob rau hauv cov kev taw qhia perpendicular mus rau lub txheej. Qhov proportional tas li (proportionality factor) siv ntawm no yog viscosity ntawm cov kua. Lub viscosity feem ntau txhais los ntawm Greek tsab ntawv "µ". Viscosity ntawm cov kua tuaj yeem ntsuas tau siv Viscometers thiab Rheometers. Chav tsev ntawm viscosity yog Pascal-seconds (los yog Nm-2s). Lub cgs system siv chav tsev "Poise", npe tom qab Jean Louis Marie Poiseuille, los ntsuas viscosity. Dynamic viscosity tseem hu ua qhov viscosity kiag li. Dynamic viscosity yog qhov kev ntsuas viscosity dav siv hauv feem ntau ntawm kev suav. Qhov no txhais tau tias yog µ lossis ɳ. SI unit ntawm dynamic viscosity yog Pascal vib nas this. Yog tias cov kua dej uas muaj viscosity ntawm 1 Pascal vib nas this yog muab tso rau ntawm ob daim hlau, thiab ib lub phaj raug thawb mus rau sab nrog ib qho kev nyuaj siab ntawm 1 Pascal, nws txav deb ntawm qhov sib npaug ntawm cov thickness ntawm cov phaj hauv 1 thib ob.
YKinematic Viscosity yog dab tsi?
Qee zaum, lub zog inertial ntawm cov kua kuj tseem ceeb nrog rau kev ntsuas viscosity. Lub zog inertial ntawm cov kua yog nyob ntawm qhov ntom ntawm cov kua. Yog li ntawd, ib lo lus tshiab hu ua kinematic viscosity yog txhais kom pab tau cov kev suav. Lub kinematic viscosity yog txhais raws li qhov piv ntawm cov dynamic viscosity rau qhov ntom ntawm cov kua. Lub kinematic viscosity raug xa mus los ntawm lo lus ν (Greek tsab ntawv nu). Kinematic viscosity muaj units ntawm meters squared muab faib los ntawm vib nas this. Chav tsev 'stoke' kuj yog siv los ntsuas qhov kinematic viscosity.
Dab tsi yog qhov txawv ntawm Kinematic Viscosity thiab Dynamic Viscosity?
• Dynamic viscosity yog ywj siab ntawm qhov ntom ntawm cov kua, tab sis kinematic viscosity nyob ntawm qhov ntom ntawm cov kua.
• Kinematic viscosity yog sib npaug rau dynamic viscosity faib los ntawm qhov ntom ntawm cov kua.
