On the basis of the quasi-steady assumption, the traditional quasi-steady friction model in liquid transients is proposed and its numerical solution with the method of characteristics is obtained.

• 采用“拟稳态”假设，推导拟稳态管壁切应力的计算公式，建立目前瞬变分析常用的传统拟稳态摩阻模型，并结合特征线法建立其数值计算模型；