- #1

tony_engin

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In a pipe flow, when the flow rate of water is increasing, reaching a critical flow rate, the flow will switch from laminar to transition flow, right? And continue the increase of flow rate will further change it to turbulent flow. The Reynolds number for these 2 transitions are obtained. When reversing the process. i.e. decreasing the flow rate of the water starting from a turbulent flow back to the laminar flow, the 2 Reynolds numbers obtained in this case (from turbulent to transition)(from transition to laminar) would be higher than that when increasing the speed. How would you explain this? Intuitively, I would attribute this to the greater vibration existed when increasing the flow rate than decreasing the flow rate..But I'm not sure if this is true.