When the hydrodynamic front reaches the ambient medium it acts like a fast-moving piston . 当流体力学波阵面抵达周围介质时,它像一个运动迅速的活塞。
2.
In the light of the interaction of oil , pipeline and ambient media and their unstable heat transmission , considering temperature dependent on physical properties and phase change of oil , a mathematical model for thermal calculation is presented 针对加热原油管道停输后油品、管道及周围介质的相互关系和它们的不稳定传热,提出了热力计算的数学模型。