## Abstract

Effects from pressure gradients, streamline convergence/divergence, and streamline curvature are often encountered in engineering wall-bounded flows. For example, as the flow passes over a fuselage or hull, it encounters a favorable pressure gradient and streamline curvature and divergence as it is accelerated past the nose. The flow then relaxes over the midbody of the vehicle before encountering an adverse pressure gradient and streamline curvature and convergence over the stern. Past the vehicle, the flow forms a wake that subsequently decays. Scaling laws and modeling approaches developed for canonical wall-bounded turbulence may require modifications when such non-equilibrium conditions are present. Previous studies that have explored the effects of pressure gradients and surface curvature have typically studied these effects separately. For example, Harun et al. (2013) showed that an adverse pressure gradient energizes turbulence while a favorable pressure gradient suppresses turbulence. Similarly, Smits et al. (1979); Muck et al. (1985) and Hoffmann et al. (1985) noted that convex surface curvature has a stabilizing effect on turbulent boundary layers while concave surface curvature has a destabilizing effect. Also, Nagib & Chauhan (2008) found that the slope of the log law region may be affected by pressure gradient and flow geometry. After strong perturbations such as a change in roughness, a short region of surface curvature, or a short region of separated flow, a non-monotonic second order recovery is often observed where the initial recovery of the u^{2}_{s} profile overshoots the equilibrium profile (Smits et al., 1979; Ding et al., 2021). Experiments on the effects of simultaneous perturbations, such as streamline curvature and divergence with pressure gradient, are very rare, and most of the existing experiments on strong perturbations have been conducted at only moderate Reynolds numbers, so the effects of high Reynolds numbers relevant for many engineering applications are also largely unknown. In this work, an axisymmetric body of revolution (BOR) is placed at the centerline of the Superpipe facility at Princeton University. The flow far upstream and downstream of the BOR is high Reynolds number, fully developed turbulent pipe flow, and the evolution of turbulence through the different conditions encountered around the body of revolution is explored. This work furthers our understanding of wall-bounded turbulence in complex flows, and provides a challenging test case for turbulence models (Visonneau et al., 2022).

Original language | English (US) |
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State | Published - 2022 |

Event | 12th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2022 - Osaka, Virtual, Japan Duration: Jul 19 2022 → Jul 22 2022 |

### Conference

Conference | 12th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2022 |
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Country/Territory | Japan |

City | Osaka, Virtual |

Period | 7/19/22 → 7/22/22 |

## All Science Journal Classification (ASJC) codes

- Aerospace Engineering
- Atmospheric Science