1) Txawm hais tias lub zog ua haujlwm ntawm cov pa cua tau qis heev, lub siab yuav tsum tau hloov kho kom tsim nyog kom ua haujlwm siab.
2) Cov phom nplaum tsis tau ntxuav, thiab cov kua nplaum ua kom khov thiab thaiv cov channel. Lub sijhawm no, cov channel yuav tsum raug tshem tawm.
3) Cov viscosity ntawm cov kua nplaum tsis tsim nyog. Yog tias viscosity siab dhau, qhov kev tiv thaiv yuav nce ntxiv, cov kua nplaum yuav tsis txuas ntxiv lossis cov kua nplaum yuav tsis tsim tawm. Yog li ntawd, nws yog qhov tsim nyog xaiv cov kua nplaum uas ua tau raws li qhov xav tau.
