The order of slip boundary condition shows an apparent influence on the friction coefficient but only a slight influence on the Nusseltnumber if compressibility is ignored.
在不考虑可压缩性因素时，滑移边界条件的阶数对阻力系数的影响较大，对换热系数的影响不是十分明显。
2
It is generally obtained by the experimental method, namely using Newton cooling formula to get tube outside heat transfer coefficient, then get the tube outside Nusseltnumber.
一般通过实验的方法求得，即运用牛顿冷却公式求出管外对流换热系数，进而求得管外努谢尔数。
3
The averaged Nusseltnumber is dramatically increased with the increase of inlet mass flow coefficient.