### Abstract

A method for generating three-dimensional, time-dependent turbulent inflow data for simulations of complex spatially developing boundary layers is described. The approach is to extract instantaneous planes of velocity data from an auxiliary simulation of a zero pressure gradient boundary layer. The auxiliary simulation is also spatially developing, but generates its own inflow conditions through a sequence of operations where the velocity field at a downstream station is rescaled and re-introduced at the inlet. This procedure is essentially a variant of the Spalart method, optimized so that an existing inflow-outflow code can be converted to an inflow-generation device through the addition of one simple subroutine. The proposed method is shown to produce a realistic turbulent boundary layer which yields statistics that are in good agreement with both experimental data and results from direct simulations. The method is used to provide inflow conditions for a large eddy simulation (LES) of a spatially evolving boundary layer spanning a momentum thickness Reynolds number interval of 1530-2150. The results from the LES calculation are compared with those from other simulations that make use of more approximate inflow conditions. When compared with the approximate inflow generation techniques, the proposed method is shown to be highly accurate, with little or no adjustment of the solution near the inlet boundary. In contrast, the other methods surveyed produce a transient near the inlet that persists several boundary layer thicknesses downstream. Lack of a transient when using the proposed method is significant since the adverse effects of inflow errors are typically minimized through a costly upstream elongation of the mesh. Extension of the method for non-zero pressure gradients is also discussed.

Original language | English (US) |
---|---|

Pages (from-to) | 233-258 |

Number of pages | 26 |

Journal | Journal of Computational Physics |

Volume | 140 |

Issue number | 2 |

DOIs | |

State | Published - Mar 1 1998 |

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### ASJC Scopus subject areas

- Computer Science Applications
- Physics and Astronomy(all)

### Cite this

*Journal of Computational Physics*,

*140*(2), 233-258. https://doi.org/10.1006/jcph.1998.5882

**Generation of Turbulent Inflow Data for Spatially-Developing Boundary Layer Simulations.** / Lund, Thomas S.; Wu, Xiaohua; Squires, Kyle.

Research output: Contribution to journal › Article

*Journal of Computational Physics*, vol. 140, no. 2, pp. 233-258. https://doi.org/10.1006/jcph.1998.5882

}

TY - JOUR

T1 - Generation of Turbulent Inflow Data for Spatially-Developing Boundary Layer Simulations

AU - Lund, Thomas S.

AU - Wu, Xiaohua

AU - Squires, Kyle

PY - 1998/3/1

Y1 - 1998/3/1

N2 - A method for generating three-dimensional, time-dependent turbulent inflow data for simulations of complex spatially developing boundary layers is described. The approach is to extract instantaneous planes of velocity data from an auxiliary simulation of a zero pressure gradient boundary layer. The auxiliary simulation is also spatially developing, but generates its own inflow conditions through a sequence of operations where the velocity field at a downstream station is rescaled and re-introduced at the inlet. This procedure is essentially a variant of the Spalart method, optimized so that an existing inflow-outflow code can be converted to an inflow-generation device through the addition of one simple subroutine. The proposed method is shown to produce a realistic turbulent boundary layer which yields statistics that are in good agreement with both experimental data and results from direct simulations. The method is used to provide inflow conditions for a large eddy simulation (LES) of a spatially evolving boundary layer spanning a momentum thickness Reynolds number interval of 1530-2150. The results from the LES calculation are compared with those from other simulations that make use of more approximate inflow conditions. When compared with the approximate inflow generation techniques, the proposed method is shown to be highly accurate, with little or no adjustment of the solution near the inlet boundary. In contrast, the other methods surveyed produce a transient near the inlet that persists several boundary layer thicknesses downstream. Lack of a transient when using the proposed method is significant since the adverse effects of inflow errors are typically minimized through a costly upstream elongation of the mesh. Extension of the method for non-zero pressure gradients is also discussed.

AB - A method for generating three-dimensional, time-dependent turbulent inflow data for simulations of complex spatially developing boundary layers is described. The approach is to extract instantaneous planes of velocity data from an auxiliary simulation of a zero pressure gradient boundary layer. The auxiliary simulation is also spatially developing, but generates its own inflow conditions through a sequence of operations where the velocity field at a downstream station is rescaled and re-introduced at the inlet. This procedure is essentially a variant of the Spalart method, optimized so that an existing inflow-outflow code can be converted to an inflow-generation device through the addition of one simple subroutine. The proposed method is shown to produce a realistic turbulent boundary layer which yields statistics that are in good agreement with both experimental data and results from direct simulations. The method is used to provide inflow conditions for a large eddy simulation (LES) of a spatially evolving boundary layer spanning a momentum thickness Reynolds number interval of 1530-2150. The results from the LES calculation are compared with those from other simulations that make use of more approximate inflow conditions. When compared with the approximate inflow generation techniques, the proposed method is shown to be highly accurate, with little or no adjustment of the solution near the inlet boundary. In contrast, the other methods surveyed produce a transient near the inlet that persists several boundary layer thicknesses downstream. Lack of a transient when using the proposed method is significant since the adverse effects of inflow errors are typically minimized through a costly upstream elongation of the mesh. Extension of the method for non-zero pressure gradients is also discussed.

UR - http://www.scopus.com/inward/record.url?scp=0000484819&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0000484819&partnerID=8YFLogxK

U2 - 10.1006/jcph.1998.5882

DO - 10.1006/jcph.1998.5882

M3 - Article

AN - SCOPUS:0000484819

VL - 140

SP - 233

EP - 258

JO - Journal of Computational Physics

JF - Journal of Computational Physics

SN - 0021-9991

IS - 2

ER -