Extension of the momentum transfer model to time-dependent pipe turbulence
We analyze a possible extension of Gioia and Chakraborty's momentum transfer model of friction in steady turbulent pipe flows to the case of time- and/or space-dependent turbulent flows. The end result is an expression for the stress at the wall as the sum of a steady and a dynamic component. T...
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Formato: | JOUR |
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Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_15393755_v85_n2_p_Calzetta |
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Sumario: | We analyze a possible extension of Gioia and Chakraborty's momentum transfer model of friction in steady turbulent pipe flows to the case of time- and/or space-dependent turbulent flows. The end result is an expression for the stress at the wall as the sum of a steady and a dynamic component. The steady part is obtained by using the instantaneous velocity in the expression for the stress at the wall of a stationary flow. The unsteady part is a weighted average over the history of the flow acceleration, with a weighting function similar to that proposed by Vardy and Brown, but naturally including the effect of spatial derivatives of the mean flow, as in the Brunone model. © 2012 American Physical Society. |
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