Because the properties of the rarefied gas are different with that of the continuum fluid, the N-S equations are not effective to solve the problems related to rarefied gas.

• 稀薄气体不同于我们通常所接触的连续介质，用以求解连续介质流动问题的N-S方程对于求解稀薄气体的流动换热问题是无效的。