TY - GEN

T1 - Coherent structures in marginally turbulent square duct flow

AU - Uhlmann, Markus

AU - Pinelli, Alfredo

AU - Sekimoto, Atsushi

AU - Kawahara, Genta

PY - 2008

Y1 - 2008

N2 - Direct numerical simulation of fully developed turbulent flow in a straight square duct was performed in order to determine the minimal requirements for self-sustaining turbulence. It was found that turbulence can be maintained for values of the bulk Reynolds number above approximately 1100, corresponding to a friction-velocity-based Reynolds number of 80. The minimum value for the streamwise period of the computational domain measures around 190 wall units, roughly independently of the Reynolds number. Furthermore, we present a characterization of the marginal state, where coherent structures are found to have significant relevance to the appearance of secondary flow of Prandtl's second kind.

AB - Direct numerical simulation of fully developed turbulent flow in a straight square duct was performed in order to determine the minimal requirements for self-sustaining turbulence. It was found that turbulence can be maintained for values of the bulk Reynolds number above approximately 1100, corresponding to a friction-velocity-based Reynolds number of 80. The minimum value for the streamwise period of the computational domain measures around 190 wall units, roughly independently of the Reynolds number. Furthermore, we present a characterization of the marginal state, where coherent structures are found to have significant relevance to the appearance of secondary flow of Prandtl's second kind.

KW - Coherent structure

KW - Marginally turbulent flow

KW - Secondary flow

KW - Square duct

UR - http://www.scopus.com/inward/record.url?scp=84861112651&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84861112651&partnerID=8YFLogxK

U2 - 10.1007/978-1-4020-6472-2_21

DO - 10.1007/978-1-4020-6472-2_21

M3 - Conference contribution

AN - SCOPUS:84861112651

SN - 9781402064715

T3 - Solid Mechanics and its Applications

SP - 137

EP - 142

BT - IUTAM Symposium on Computational Physics and New Perspectives in Turbulence - Proceedings of the IUTAM Symposium on Computational Physics and New Perspectives in Turbulence

T2 - IUTAM Symposium on Computational Physics and New Perspectives in Turbulence

Y2 - 11 September 2006 through 14 September 2006

ER -