Evolution of mushroom-type structures behind a heated cylinder

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Abstract

The three-dimensional transition in the wake flow behind a heated cylinder occurs at a much lower Reynolds number than for the unheated case. The three-dimensional transition is initialized in the near-wake by the formation of -shaped structures and manifests itself in the far-wake as escaping mushroom-type structures from the upper vortices. In this study, both experimental and numerical techniques are used to investigate the origin and development of these mushroom-type structures. The formation of the mushroom-type structures is associated with the occurrence of -shaped vortices in the near-wake. Hot fluid between the legs and the head of the -shaped structure is lifted up. This lift-up process together with the action of buoyancy pulls out hot fluid from the upper vortex cores, resulting in a mushroom-type structure, which is comprised of a so-called stem and cap. Hot fluid is continuously transported through the stem to the advancing front of the mushroom-type structure. Finally, a pinch-off phenomenon is observed of the cap, ending up as a buoyant vortex ring. An analytical model is presented for the pinch-off process.
Original languageEnglish
Article number064103
Pages (from-to)064103-1/11
Number of pages11
JournalPhysics of Fluids
Volume19
Issue number6
DOIs
Publication statusPublished - 2007

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near wakes
vortices
stems
caps
wakes
fluids
vortex rings
low Reynolds number
buoyancy
occurrences

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@article{46da88c9084b43afaeb201379e76a8c5,
title = "Evolution of mushroom-type structures behind a heated cylinder",
abstract = "The three-dimensional transition in the wake flow behind a heated cylinder occurs at a much lower Reynolds number than for the unheated case. The three-dimensional transition is initialized in the near-wake by the formation of -shaped structures and manifests itself in the far-wake as escaping mushroom-type structures from the upper vortices. In this study, both experimental and numerical techniques are used to investigate the origin and development of these mushroom-type structures. The formation of the mushroom-type structures is associated with the occurrence of -shaped vortices in the near-wake. Hot fluid between the legs and the head of the -shaped structure is lifted up. This lift-up process together with the action of buoyancy pulls out hot fluid from the upper vortex cores, resulting in a mushroom-type structure, which is comprised of a so-called stem and cap. Hot fluid is continuously transported through the stem to the advancing front of the mushroom-type structure. Finally, a pinch-off phenomenon is observed of the cap, ending up as a buoyant vortex ring. An analytical model is presented for the pinch-off process.",
author = "M. Ren and C.C.M. Rindt and {Steenhoven, van}, A.A.",
year = "2007",
doi = "10.1063/1.2741397",
language = "English",
volume = "19",
pages = "064103--1/11",
journal = "Physics of Fluids",
issn = "1070-6631",
publisher = "American Institute of Physics",
number = "6",

}

Evolution of mushroom-type structures behind a heated cylinder. / Ren, M.; Rindt, C.C.M.; Steenhoven, van, A.A.

In: Physics of Fluids, Vol. 19, No. 6, 064103, 2007, p. 064103-1/11.

Research output: Contribution to journalArticleAcademicpeer-review

TY - JOUR

T1 - Evolution of mushroom-type structures behind a heated cylinder

AU - Ren, M.

AU - Rindt, C.C.M.

AU - Steenhoven, van, A.A.

PY - 2007

Y1 - 2007

N2 - The three-dimensional transition in the wake flow behind a heated cylinder occurs at a much lower Reynolds number than for the unheated case. The three-dimensional transition is initialized in the near-wake by the formation of -shaped structures and manifests itself in the far-wake as escaping mushroom-type structures from the upper vortices. In this study, both experimental and numerical techniques are used to investigate the origin and development of these mushroom-type structures. The formation of the mushroom-type structures is associated with the occurrence of -shaped vortices in the near-wake. Hot fluid between the legs and the head of the -shaped structure is lifted up. This lift-up process together with the action of buoyancy pulls out hot fluid from the upper vortex cores, resulting in a mushroom-type structure, which is comprised of a so-called stem and cap. Hot fluid is continuously transported through the stem to the advancing front of the mushroom-type structure. Finally, a pinch-off phenomenon is observed of the cap, ending up as a buoyant vortex ring. An analytical model is presented for the pinch-off process.

AB - The three-dimensional transition in the wake flow behind a heated cylinder occurs at a much lower Reynolds number than for the unheated case. The three-dimensional transition is initialized in the near-wake by the formation of -shaped structures and manifests itself in the far-wake as escaping mushroom-type structures from the upper vortices. In this study, both experimental and numerical techniques are used to investigate the origin and development of these mushroom-type structures. The formation of the mushroom-type structures is associated with the occurrence of -shaped vortices in the near-wake. Hot fluid between the legs and the head of the -shaped structure is lifted up. This lift-up process together with the action of buoyancy pulls out hot fluid from the upper vortex cores, resulting in a mushroom-type structure, which is comprised of a so-called stem and cap. Hot fluid is continuously transported through the stem to the advancing front of the mushroom-type structure. Finally, a pinch-off phenomenon is observed of the cap, ending up as a buoyant vortex ring. An analytical model is presented for the pinch-off process.

U2 - 10.1063/1.2741397

DO - 10.1063/1.2741397

M3 - Article

VL - 19

SP - 064103-1/11

JO - Physics of Fluids

JF - Physics of Fluids

SN - 1070-6631

IS - 6

M1 - 064103

ER -