2D RANS and LES Simulations of Turbulent Flow inside a Differentially Heated Square Cavity

A Dehbi, M Aksouh, Jarmo Kalilainen

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

Abstract

A series of analytical and experimental studies have been conducted at the Paul Scherrer Institut (PSI) to investigate the interactions between turbulent flow and particles inside a model containment consisting of a differentially heated cubical cavity (DHC). Analytical efforts have involved 3D Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) of the flow at Rayleigh number (Ra) of 109 using spectral and spectral element codes, respectively. While providing deep insights of the flow dynamics, these 3D simulations are very time-consuming, and their potential extension to higher Ra numbers typical of reactor conditions is not possible with current CPU resources. In this study therefore, we employ RANS and LES in 2D using the commercial code ANSYS Fluent and compare the fluid flow results against the previous 2D DNS database. We show that the RANS predictions deviate substantially from the DNS data, missing the locations of the recirculation regions along the hot/cold walls. More importantly, the turbulence parameters (turbulent kinetic energy, Reynolds stresses) are not well captured by the RANS models despite the rather simple geometry of the problem. On the other hand, the 2D LES compares well with the 2D DNS database for the mean flow as well as turbulent statistics. This comes at the expense of a much larger computational effort compared to RANS. However, the 2D LES methodology can still be extended with the current CPU resources to tackle higher Ra numbers, and hopefully approach turbulence levels that are comparable to those of nuclear containment applications
Original languageEnglish
Title of host publicationProceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15)
EditionUSB flash drive
Publication statusPublished - 2013
MoE publication typeA4 Article in a conference publication
Event15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-15 - Pisa, Italy
Duration: 12 May 201315 May 2013

Conference

Conference15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-15
Abbreviated titleNURETH-15
CountryItaly
CityPisa
Period12/05/1315/05/13

Fingerprint

large eddy simulation
direct numerical simulation
turbulent flow
cavities
containment
resources
simulation
turbulence
cold walls
Reynolds stress
Rayleigh number
fluid flow
kinetic energy
reactors
statistics
methodology
geometry
predictions
interactions

Cite this

Dehbi, A., Aksouh, M., & Kalilainen, J. (2013). 2D RANS and LES Simulations of Turbulent Flow inside a Differentially Heated Square Cavity. In Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15) (USB flash drive ed.)
Dehbi, A ; Aksouh, M ; Kalilainen, Jarmo. / 2D RANS and LES Simulations of Turbulent Flow inside a Differentially Heated Square Cavity. Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15). USB flash drive. ed. 2013.
@inproceedings{720c08271361408d90430c09b08f4dc9,
title = "2D RANS and LES Simulations of Turbulent Flow inside a Differentially Heated Square Cavity",
abstract = "A series of analytical and experimental studies have been conducted at the Paul Scherrer Institut (PSI) to investigate the interactions between turbulent flow and particles inside a model containment consisting of a differentially heated cubical cavity (DHC). Analytical efforts have involved 3D Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) of the flow at Rayleigh number (Ra) of 109 using spectral and spectral element codes, respectively. While providing deep insights of the flow dynamics, these 3D simulations are very time-consuming, and their potential extension to higher Ra numbers typical of reactor conditions is not possible with current CPU resources. In this study therefore, we employ RANS and LES in 2D using the commercial code ANSYS Fluent and compare the fluid flow results against the previous 2D DNS database. We show that the RANS predictions deviate substantially from the DNS data, missing the locations of the recirculation regions along the hot/cold walls. More importantly, the turbulence parameters (turbulent kinetic energy, Reynolds stresses) are not well captured by the RANS models despite the rather simple geometry of the problem. On the other hand, the 2D LES compares well with the 2D DNS database for the mean flow as well as turbulent statistics. This comes at the expense of a much larger computational effort compared to RANS. However, the 2D LES methodology can still be extended with the current CPU resources to tackle higher Ra numbers, and hopefully approach turbulence levels that are comparable to those of nuclear containment applications",
author = "A Dehbi and M Aksouh and Jarmo Kalilainen",
note = "Project code: TRAFI 77652 {"}Due to limited time left for publication of the paper ID-582 in the proceedings, it was not possible to introduce further corrections and editing{"}",
year = "2013",
language = "English",
booktitle = "Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15)",
edition = "USB flash drive",

}

Dehbi, A, Aksouh, M & Kalilainen, J 2013, 2D RANS and LES Simulations of Turbulent Flow inside a Differentially Heated Square Cavity. in Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15). USB flash drive edn, 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH-15, Pisa, Italy, 12/05/13.

2D RANS and LES Simulations of Turbulent Flow inside a Differentially Heated Square Cavity. / Dehbi, A; Aksouh, M; Kalilainen, Jarmo.

Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15). USB flash drive. ed. 2013.

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

TY - GEN

T1 - 2D RANS and LES Simulations of Turbulent Flow inside a Differentially Heated Square Cavity

AU - Dehbi, A

AU - Aksouh, M

AU - Kalilainen, Jarmo

N1 - Project code: TRAFI 77652 "Due to limited time left for publication of the paper ID-582 in the proceedings, it was not possible to introduce further corrections and editing"

PY - 2013

Y1 - 2013

N2 - A series of analytical and experimental studies have been conducted at the Paul Scherrer Institut (PSI) to investigate the interactions between turbulent flow and particles inside a model containment consisting of a differentially heated cubical cavity (DHC). Analytical efforts have involved 3D Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) of the flow at Rayleigh number (Ra) of 109 using spectral and spectral element codes, respectively. While providing deep insights of the flow dynamics, these 3D simulations are very time-consuming, and their potential extension to higher Ra numbers typical of reactor conditions is not possible with current CPU resources. In this study therefore, we employ RANS and LES in 2D using the commercial code ANSYS Fluent and compare the fluid flow results against the previous 2D DNS database. We show that the RANS predictions deviate substantially from the DNS data, missing the locations of the recirculation regions along the hot/cold walls. More importantly, the turbulence parameters (turbulent kinetic energy, Reynolds stresses) are not well captured by the RANS models despite the rather simple geometry of the problem. On the other hand, the 2D LES compares well with the 2D DNS database for the mean flow as well as turbulent statistics. This comes at the expense of a much larger computational effort compared to RANS. However, the 2D LES methodology can still be extended with the current CPU resources to tackle higher Ra numbers, and hopefully approach turbulence levels that are comparable to those of nuclear containment applications

AB - A series of analytical and experimental studies have been conducted at the Paul Scherrer Institut (PSI) to investigate the interactions between turbulent flow and particles inside a model containment consisting of a differentially heated cubical cavity (DHC). Analytical efforts have involved 3D Direct Numerical Simulations (DNS) and Large Eddy Simulations (LES) of the flow at Rayleigh number (Ra) of 109 using spectral and spectral element codes, respectively. While providing deep insights of the flow dynamics, these 3D simulations are very time-consuming, and their potential extension to higher Ra numbers typical of reactor conditions is not possible with current CPU resources. In this study therefore, we employ RANS and LES in 2D using the commercial code ANSYS Fluent and compare the fluid flow results against the previous 2D DNS database. We show that the RANS predictions deviate substantially from the DNS data, missing the locations of the recirculation regions along the hot/cold walls. More importantly, the turbulence parameters (turbulent kinetic energy, Reynolds stresses) are not well captured by the RANS models despite the rather simple geometry of the problem. On the other hand, the 2D LES compares well with the 2D DNS database for the mean flow as well as turbulent statistics. This comes at the expense of a much larger computational effort compared to RANS. However, the 2D LES methodology can still be extended with the current CPU resources to tackle higher Ra numbers, and hopefully approach turbulence levels that are comparable to those of nuclear containment applications

M3 - Conference article in proceedings

BT - Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15)

ER -

Dehbi A, Aksouh M, Kalilainen J. 2D RANS and LES Simulations of Turbulent Flow inside a Differentially Heated Square Cavity. In Proceedings of 15th International Topical Meeting on Nuclear Reactor Thermal Hydraulics (NURETH-15). USB flash drive ed. 2013