He, K and Seddighi, M and He, S (2015) DNS study of a pipe flow following a step increase in flow rate. International Journal of Heat and Fluid Flow, 57. pp. 130-141. ISSN 0142-727X
He_Seddighi_He_2016.pdf - Published Version
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Direct numerical simulation (DNS) is conducted to study the transient flow in a pipe following a near-step increase of flow rate from an initial turbulent flow. The results are compared with those of the transient flow in a channel reported in He and Seddighi (2013). It is shown that the flow again exhibits a laminar–turbulent transition, similar to that in a channel. The behaviours of the flow in a pipe and a channel are the same in the near-wall region, but there are significant differences in the centre of the flow. The correlation between the critical Reynolds number and free stream turbulence previously established for a channel flow has been shown to be applicable to the pipe flow. The responses of turbulent viscosity, vorticity Reynolds number, and budget terms are analysed. Some significant differences have been found to exist between the developments of the vorticity Reynolds number in the pipe and channel flows.
Keywords: Transient flow; Pipe flow; Flow acceleration; Bypass transition
|Uncontrolled Keywords:||0901 Aerospace Engineering, 0913 Mechanical Engineering, 0915 Interdisciplinary Engineering|
|Subjects:||T Technology > TJ Mechanical engineering and machinery|
|Divisions:||Maritime and Mechanical Engineering|
|Date Deposited:||21 Dec 2015 08:53|
|Last Modified:||18 Nov 2016 10:55|
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