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Effects of the Temporal Increase Rate of Reynolds Number on Turbulent Channel Flows
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 Title & Authors
Effects of the Temporal Increase Rate of Reynolds Number on Turbulent Channel Flows
Jung, Seo Yoon; Kim, Kyoungyoun;
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Effects of the increase rate of Reynold number on near-wall turbulent structures are investigated by performing direct numerical simulations of transient turbulent channel flows. The simulations were started with the fully-developed turbulent channel flow at , then temporal accelerations were applied. During the acceleration, the Reynolds number, based on the channel width and the bulk mean velocity, increased almost linearly from 5600 to 13600. To elucidate the effects of flow acceleration rates on near-wall turbulence, a wide range of durations for acceleration were selected. Various turbulent statistics and instantaneous flow fields revealed that the rapid increase of flow rate invoked bypass-transition like phenomena in the transient flow. By contrast, the flow evolved progressively and the bypass transition did not clearly occur during mild flow acceleration. The present study suggests that the transition to the new turbulent regime in transient channel flow is mainly affected by the flow acceleration rate, not by the ratio of the final and initial Reynolds numbers.
Transient Channel Flow;Direct Numerical Simulation;Bypass Transition;
 Cited by
Kataoka, K., Kawabata, T. and Miki, K., 1975, "The Start-up Response of Pipe Flow to a Step Change in Flow Rate," Journal of Chemical Engineering of Japan, Vol. 8, No. 4, pp. 266-271. crossref(new window)

Mizushina, T., Maruyama, T. and Hirasawa, H., 1975, "Structure of the Turbulence in Pulsating Pipe Flows," Journal of Chemical Engineering of Japan, Vol. 8, No. 3, pp. 210-216. crossref(new window)

He, S. and Jackson, J. D., 2000, "A Study of Turbulence Under Conditions of Transient Flow in a Pipe," J. Fluid Mech., Vol. 408, pp. 1-38. crossref(new window)

Greenblatt, D. and Moss, E. A., 2004, "Rapid Temporal Acceleration of a Turbulent Pipe Flow," J. Fluid Mech., Vol. 514, pp. 65-75. crossref(new window)

Chung, Y. M., 2005, "Unsteady Turbulent Flow with Sudden Pressure Gradient Changes," Int. J. Numer. Meth. Fl., Vol. 47, pp. 925-930. crossref(new window)

Jung, S.Y. and Chung, Y. M., 2012, "Large-eddy Simulation of Accelerated Turbulent Flow in a Circular Pipe," Int. J. Heat Fluid Fl., Vol. 33, No. 1, pp. 1-8. crossref(new window)

He, S. and Seddighi, M., 2013, "Turbulence in Transient Channel Flow," J. Fluid Mech., Vol. 715, pp. 60-102. crossref(new window)

He, S. and Seddighi, M., 2015, "Transition of Transient Channel Flow After a Change in Reynolds Number," J. Fluid Mech., Vol. 764, pp. 395-427. crossref(new window)

Kim, K., Sung, H. J. and Adrian, R. J., 2008, "Effects of Background Noise on Generating Coherent Packets of Hairpin Vortices," Phys. Fluids, Vol. 20, pp. 105-107.

Dean, R. B., 1978, "Reynolds Number Dependence of Skin Friction and Other Bulk Flow Variables in Two-dimensional Rectangular Duct Flow," J. Fluid Eng., Vol. 100, pp. 215-223. crossref(new window)

Chakraborty, P., Balachandar, S. and Adrian, R. J., 2005, "On the Relationships Between Local Vortex Identification Schemes," J. Fluid Mech., Vol. 535, pp. 189-214. crossref(new window)