Abstract
Tight fuel lattices are characterized by quasi-periodical flow oscillations between subchannels, as first observed by Hooper ([1]). The above mentioned phenomena are of inherently unstable nature and, even if no conclusive theoretical study on the subject have been published, the evidence shown to this point suggests that the oscillations are connected to interactions between eddy structures of turbulent flows in adjacent subchannels ([2]). This coherent structures travel in the direction of homogeneous turbulence, in a fashion that strongly recalls the Von-Karman Vortex Street ([3]). Analogous behaviours have been observed for arrays of arbitrarily shaped channels ([4]), within certain range of the geometric parameters. Numerical simulation of these phenomena is challenging, and a completely satisfactory explanation of their cause is not available. A modelling for these phenomena is at least problematic to achieve since they are turbulence driven. This paper aims to address the use of POD (Proper Orthonormal Decomposition) to reduce the Navier-Stokes equation to a set of ordinary differential equations ([5]).The set of ODE is solved numerically, and a series of comparison with experimental and numerical data is offered, in order to test the predicting capability of the models proposed.
| Original language | English (US) |
|---|---|
| Title of host publication | Proceedings - 12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12 |
| State | Published - Dec 1 2007 |
| Event | 12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12 - Pittsburgh, PA, United States Duration: Sep 30 2007 → Oct 4 2007 |
Publication series
| Name | Proceedings - 12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12 |
|---|
Other
| Other | 12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12 |
|---|---|
| Country | United States |
| City | Pittsburgh, PA |
| Period | 9/30/07 → 10/4/07 |
Fingerprint
All Science Journal Classification (ASJC) codes
- Nuclear Energy and Engineering
- Nuclear and High Energy Physics
Cite this
}
Toward a dynamical systems approach for the understanding of turbulent flow pulsations between subchannels. / Merzari, Elia; Ninokata, H.
Proceedings - 12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12. 2007. (Proceedings - 12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12).Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
TY - GEN
T1 - Toward a dynamical systems approach for the understanding of turbulent flow pulsations between subchannels
AU - Merzari, Elia
AU - Ninokata, H.
PY - 2007/12/1
Y1 - 2007/12/1
N2 - Tight fuel lattices are characterized by quasi-periodical flow oscillations between subchannels, as first observed by Hooper ([1]). The above mentioned phenomena are of inherently unstable nature and, even if no conclusive theoretical study on the subject have been published, the evidence shown to this point suggests that the oscillations are connected to interactions between eddy structures of turbulent flows in adjacent subchannels ([2]). This coherent structures travel in the direction of homogeneous turbulence, in a fashion that strongly recalls the Von-Karman Vortex Street ([3]). Analogous behaviours have been observed for arrays of arbitrarily shaped channels ([4]), within certain range of the geometric parameters. Numerical simulation of these phenomena is challenging, and a completely satisfactory explanation of their cause is not available. A modelling for these phenomena is at least problematic to achieve since they are turbulence driven. This paper aims to address the use of POD (Proper Orthonormal Decomposition) to reduce the Navier-Stokes equation to a set of ordinary differential equations ([5]).The set of ODE is solved numerically, and a series of comparison with experimental and numerical data is offered, in order to test the predicting capability of the models proposed.
AB - Tight fuel lattices are characterized by quasi-periodical flow oscillations between subchannels, as first observed by Hooper ([1]). The above mentioned phenomena are of inherently unstable nature and, even if no conclusive theoretical study on the subject have been published, the evidence shown to this point suggests that the oscillations are connected to interactions between eddy structures of turbulent flows in adjacent subchannels ([2]). This coherent structures travel in the direction of homogeneous turbulence, in a fashion that strongly recalls the Von-Karman Vortex Street ([3]). Analogous behaviours have been observed for arrays of arbitrarily shaped channels ([4]), within certain range of the geometric parameters. Numerical simulation of these phenomena is challenging, and a completely satisfactory explanation of their cause is not available. A modelling for these phenomena is at least problematic to achieve since they are turbulence driven. This paper aims to address the use of POD (Proper Orthonormal Decomposition) to reduce the Navier-Stokes equation to a set of ordinary differential equations ([5]).The set of ODE is solved numerically, and a series of comparison with experimental and numerical data is offered, in order to test the predicting capability of the models proposed.
UR - http://www.scopus.com/inward/record.url?scp=80053170996&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80053170996&partnerID=8YFLogxK
M3 - Conference contribution
AN - SCOPUS:80053170996
SN - 0894480588
SN - 9780894480584
T3 - Proceedings - 12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12
BT - Proceedings - 12th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-12
ER -