Qhov cuam tshuam ntawm cov dej khov rau ntawm kev hloov pauv kub yog qhov tseem ceeb tshwj xeeb tshaj yog rau high-velocity flows , viscous flows txawm nyob rau nruab nrab nrawm, rau cov kua dej nrog tus lej Prandtl tus lej Prandtl Hauv cov teeb meem hloov hluav taws xob, tus lej Prandtl tswj cov txheeb ze ntawm lub zog thiab cov txheej txheem thermal ciam teb. Thaum Pr me me, nws txhais tau hais tias cov cua kub diffuses sai dua piv rau qhov nrawm (momentum). https://en.wikipedia.org › wiki › Prandtl_number
Prandtl tus lej - Wikipedia
thiab cov nrawm nrawm nrog cov phab ntsa me me-rau-kua dej sib txawv lossis nrog cov phab ntsa qis qis thiab ntws los ntawm …
Thaum twg peb tuaj yeem tsis quav ntsej cov viscous dissipation?
Tsis quav ntsej cov kua nplaum? Nyob rau hauv dab tsi tej yam kev mob muaj peev xwm tsis quav ntsej viscous dissipation thaum ua qauv ib qho system, yog hais tias tus khiav yog laminar, cov dej ua hauj lwm yog roj thiab thaum nws yog ib tug kua.
viscous dissipation hauv cov tshuab ua kua dej yog dab tsi?
Nyob rau hauv cov kua dej khov lub viscosity ntawm cov kua yuav siv lub zog los ntawm kev txav ntawm cov kua (kinetic zog) thiab hloov mus rau hauv lub zog ntawm cov kua. Qhov ntawd txhais tau tias ua kom cov kua dej ua kom sov. Cov txheej txheem no yog ib feem irreversible thiab yog hu ua dissipation, los yog viscous dissipation.
Yuav ua li cas nkim cua sov ua kom zoo?
Nqus cua sov yog qhov tshwm sim ntawm qhov kub thiab txias vim qhov viscouscuam tshuam ntawm cov kua dej los yog kua-phab ntsa interface. Nws yuav tsum feem ntau yog siv rau compressible flows los yog qhov twg viscous rog yog qhov tseem ceeb (lubrication, polymer ua)
viscous cua sov yog dab tsi?
Definition. Cov cua kub hnyav sawv cev cov txiaj ntsig ntawm cov txheej txheem irreversible los ntawmtxhais tau tias cov haujlwm ua los ntawm cov kua dej ntawm cov khaubncaws sab nraud povtseg vim qhov kev txiav txim ntawm shear rog hloov mus rau hauv tshav kub.
