### Abstract

We investigate the stability of a fluid confined between two cylinders that rotate at same constant angular speed. In the case of infinite cylinders, or endwalls rotating with the cylinders, the flow is in solid-body rotation and hence linearly stable for any rotation speed. However, when the endwalls are stationary, a large-scale circulation is driven by radially inward boundary layer flow on the endwalls. For sufficiently high angular speeds, this circulation becomes unstable to azimuthal waves. As the length-to-gap aspect ratio of the system is increased, a wealth of instabilities is revealed. It is particularly interesting that for all these instabilities the associated energy is localized in the equatorial region, as far from the endwalls as possible. This shows that care must be taken when assuming localized endwall effects in simplified models.

Original language | English (US) |
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Article number | 104104 |

Journal | Physics of Fluids |

Volume | 20 |

Issue number | 10 |

DOIs | |

State | Published - 2008 |

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### ASJC Scopus subject areas

- Condensed Matter Physics

### Cite this

*Physics of Fluids*,

*20*(10), [104104]. https://doi.org/10.1063/1.2996326

**Global endwall effects on centrifugally stable flows.** / Avila, Marc; Grimes, Matt; Lopez, Juan; Marques, Francisco.

Research output: Contribution to journal › Article

*Physics of Fluids*, vol. 20, no. 10, 104104. https://doi.org/10.1063/1.2996326

}

TY - JOUR

T1 - Global endwall effects on centrifugally stable flows

AU - Avila, Marc

AU - Grimes, Matt

AU - Lopez, Juan

AU - Marques, Francisco

PY - 2008

Y1 - 2008

N2 - We investigate the stability of a fluid confined between two cylinders that rotate at same constant angular speed. In the case of infinite cylinders, or endwalls rotating with the cylinders, the flow is in solid-body rotation and hence linearly stable for any rotation speed. However, when the endwalls are stationary, a large-scale circulation is driven by radially inward boundary layer flow on the endwalls. For sufficiently high angular speeds, this circulation becomes unstable to azimuthal waves. As the length-to-gap aspect ratio of the system is increased, a wealth of instabilities is revealed. It is particularly interesting that for all these instabilities the associated energy is localized in the equatorial region, as far from the endwalls as possible. This shows that care must be taken when assuming localized endwall effects in simplified models.

AB - We investigate the stability of a fluid confined between two cylinders that rotate at same constant angular speed. In the case of infinite cylinders, or endwalls rotating with the cylinders, the flow is in solid-body rotation and hence linearly stable for any rotation speed. However, when the endwalls are stationary, a large-scale circulation is driven by radially inward boundary layer flow on the endwalls. For sufficiently high angular speeds, this circulation becomes unstable to azimuthal waves. As the length-to-gap aspect ratio of the system is increased, a wealth of instabilities is revealed. It is particularly interesting that for all these instabilities the associated energy is localized in the equatorial region, as far from the endwalls as possible. This shows that care must be taken when assuming localized endwall effects in simplified models.

UR - http://www.scopus.com/inward/record.url?scp=55849107724&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=55849107724&partnerID=8YFLogxK

U2 - 10.1063/1.2996326

DO - 10.1063/1.2996326

M3 - Article

AN - SCOPUS:55849107724

VL - 20

JO - Physics of Fluids

JF - Physics of Fluids

SN - 1070-6631

IS - 10

M1 - 104104

ER -