### Abstract

The pressure distribution and the hydrodynamic forces on a circular cylinder placed near a plane boundary are investigated experimentally over a range of Reynolds numbers (Re) of 1.1 × 10^{5}–4.3 × 10^{5} and gap (G) to cylinder diameter (D) ratio (G/D) of 0–1.0. The objective of the study is to quantify the influence of G/D on the force coefficients when the boundary layer on the cylinder surface transits from laminar to turbulent. The hydrodynamic forces acting on the cylinder are obtained by integrating the measured pressure around the cylinder surface. A significant drag reduction from about 0.9 to 0.35 is observed for G/D≥0.5 in the range of Re = 1.9 × 10^{5}–2.7 × 10^{5}. At smaller G/D values of 0.25 and 0.1, the drag coefficient shows much less reduction than those observed at larger G/D values. No obvious drag reduction is found at G/D = 0.01 and 0. Based on the observed features of pressure distributions and force coefficients, the boundary layer transition from laminar to turbulent is inferred for all the gap ratios (G/D = 0 ∼ ∞).

Original language | English |
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Pages (from-to) | 133-142 |

Number of pages | 10 |

Journal | Ocean Engineering |

Volume | 154 |

DOIs | |

Publication status | Published - 15 Apr 2018 |

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### Cite this

*Ocean Engineering*,

*154*, 133-142. https://doi.org/10.1016/j.oceaneng.2018.01.011

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*Ocean Engineering*, vol. 154, pp. 133-142. https://doi.org/10.1016/j.oceaneng.2018.01.011

**Drag crisis of a circular cylinder near a plane boundary.** / Yang, F.; An, H.; Cheng, L.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Drag crisis of a circular cylinder near a plane boundary

AU - Yang, F.

AU - An, H.

AU - Cheng, L.

PY - 2018/4/15

Y1 - 2018/4/15

N2 - The pressure distribution and the hydrodynamic forces on a circular cylinder placed near a plane boundary are investigated experimentally over a range of Reynolds numbers (Re) of 1.1 × 105–4.3 × 105 and gap (G) to cylinder diameter (D) ratio (G/D) of 0–1.0. The objective of the study is to quantify the influence of G/D on the force coefficients when the boundary layer on the cylinder surface transits from laminar to turbulent. The hydrodynamic forces acting on the cylinder are obtained by integrating the measured pressure around the cylinder surface. A significant drag reduction from about 0.9 to 0.35 is observed for G/D≥0.5 in the range of Re = 1.9 × 105–2.7 × 105. At smaller G/D values of 0.25 and 0.1, the drag coefficient shows much less reduction than those observed at larger G/D values. No obvious drag reduction is found at G/D = 0.01 and 0. Based on the observed features of pressure distributions and force coefficients, the boundary layer transition from laminar to turbulent is inferred for all the gap ratios (G/D = 0 ∼ ∞).

AB - The pressure distribution and the hydrodynamic forces on a circular cylinder placed near a plane boundary are investigated experimentally over a range of Reynolds numbers (Re) of 1.1 × 105–4.3 × 105 and gap (G) to cylinder diameter (D) ratio (G/D) of 0–1.0. The objective of the study is to quantify the influence of G/D on the force coefficients when the boundary layer on the cylinder surface transits from laminar to turbulent. The hydrodynamic forces acting on the cylinder are obtained by integrating the measured pressure around the cylinder surface. A significant drag reduction from about 0.9 to 0.35 is observed for G/D≥0.5 in the range of Re = 1.9 × 105–2.7 × 105. At smaller G/D values of 0.25 and 0.1, the drag coefficient shows much less reduction than those observed at larger G/D values. No obvious drag reduction is found at G/D = 0.01 and 0. Based on the observed features of pressure distributions and force coefficients, the boundary layer transition from laminar to turbulent is inferred for all the gap ratios (G/D = 0 ∼ ∞).

KW - Circular cylinder

KW - Critical Reynolds number

KW - Drag crisis

KW - Wall proximity effect

UR - http://www.scopus.com/inward/record.url?scp=85044354591&partnerID=8YFLogxK

U2 - 10.1016/j.oceaneng.2018.01.011

DO - 10.1016/j.oceaneng.2018.01.011

M3 - Article

VL - 154

SP - 133

EP - 142

JO - Ocean Engineering

JF - Ocean Engineering

SN - 0029-8018

ER -