### Abstract

The Reynolds Averaged Navier-Stokes (RANS-) equation for the mean velocity field is statistically unclosed. Previous research by Parks et al. (1998) has identified a class of algebraic closures that relate the turbulent flux of momentum to a prestress induced by fluctuations in the instantaneous Reynolds stress and fluctuations in the pressure field. The new approach shifts the turbulence closure problem from the anisotropic component of the Reynolds stress to the anisotropic component of a prestress with the result that the turbulent momentum flux is not frame indifferent at the mesoscale relevant to turbulent flows. The closure hypothesis yields an explicit non-linear algebraic relationship between the turbulent momentum flux and a non-negative, symmetric, dyadic-valued operator that depends on the mean velocity gradient and a relaxation time associated with the local space-time structure of the turbulence. The eigenvalues of the resulting turbulent momentum flux are non-negative for all flows. Benchmark experimental and computational data are used to determine the parameters in the new closure. The application of the closure to homogeneous shear in noninertial frames and other flows in inertial frames will be presented and compared with direct numerical simulations.

Original language | English (US) |
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Title of host publication | AIChE Annual Meeting, Conference Proceedings |

Pages | 644 |

Number of pages | 1 |

State | Published - 2005 |

Externally published | Yes |

Event | 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase - Cincinnati, OH, United States |

### Other

Other | 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase |
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Country | United States |

City | Cincinnati, OH |

Period | 10/30/05 → 11/4/05 |

### Profile

### ASJC Scopus subject areas

- Engineering(all)

### Cite this

*AIChE Annual Meeting, Conference Proceedings*(pp. 644)

**Reynolds stress closure for strongly swirling flows.** / Koppula, Karuna S.; Petty, Charles A.; Benard, Andre.

Research output: Chapter in Book/Report/Conference proceeding › Conference contribution

*AIChE Annual Meeting, Conference Proceedings.*pp. 644, 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Cincinnati, OH, United States, 30-4 November.

}

TY - CHAP

T1 - Reynolds stress closure for strongly swirling flows

AU - Koppula,Karuna S.

AU - Petty,Charles A.

AU - Benard,Andre

PY - 2005

Y1 - 2005

N2 - The Reynolds Averaged Navier-Stokes (RANS-) equation for the mean velocity field is statistically unclosed. Previous research by Parks et al. (1998) has identified a class of algebraic closures that relate the turbulent flux of momentum to a prestress induced by fluctuations in the instantaneous Reynolds stress and fluctuations in the pressure field. The new approach shifts the turbulence closure problem from the anisotropic component of the Reynolds stress to the anisotropic component of a prestress with the result that the turbulent momentum flux is not frame indifferent at the mesoscale relevant to turbulent flows. The closure hypothesis yields an explicit non-linear algebraic relationship between the turbulent momentum flux and a non-negative, symmetric, dyadic-valued operator that depends on the mean velocity gradient and a relaxation time associated with the local space-time structure of the turbulence. The eigenvalues of the resulting turbulent momentum flux are non-negative for all flows. Benchmark experimental and computational data are used to determine the parameters in the new closure. The application of the closure to homogeneous shear in noninertial frames and other flows in inertial frames will be presented and compared with direct numerical simulations.

AB - The Reynolds Averaged Navier-Stokes (RANS-) equation for the mean velocity field is statistically unclosed. Previous research by Parks et al. (1998) has identified a class of algebraic closures that relate the turbulent flux of momentum to a prestress induced by fluctuations in the instantaneous Reynolds stress and fluctuations in the pressure field. The new approach shifts the turbulence closure problem from the anisotropic component of the Reynolds stress to the anisotropic component of a prestress with the result that the turbulent momentum flux is not frame indifferent at the mesoscale relevant to turbulent flows. The closure hypothesis yields an explicit non-linear algebraic relationship between the turbulent momentum flux and a non-negative, symmetric, dyadic-valued operator that depends on the mean velocity gradient and a relaxation time associated with the local space-time structure of the turbulence. The eigenvalues of the resulting turbulent momentum flux are non-negative for all flows. Benchmark experimental and computational data are used to determine the parameters in the new closure. The application of the closure to homogeneous shear in noninertial frames and other flows in inertial frames will be presented and compared with direct numerical simulations.

UR - http://www.scopus.com/inward/record.url?scp=33645562234&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33645562234&partnerID=8YFLogxK

M3 - Conference contribution

SP - 644

BT - AIChE Annual Meeting, Conference Proceedings

ER -