Modeling of Cube Array Roughness: RANS, LES, and DNS

Flow over arrays of cubes is an extensively studied model problem for rough wall turbulent boundary layers. While considerable research has been performed in computationally investigating these topologies using DNS and LES, the ability of sublayer-resolved RANS to predict the bulk flow phenomena of these systems is relatively unexplored, especially at low and high packing densities. Here, RANS simulations are conducted on six different packing densities of cubes in aligned and staggered configurations. The packing densities investigated span from what would classically be defined as isolated, up to those in the d-type roughness regime, filling in the gap in the present literature. Three different sublayer-resolved turbulence closure models were tested for each case; a low Reynolds number k-ε model, the Menter k-ω SST model, and a full Reynolds stress model. Comparisons of the velocity fields, secondary flow features, and drag coefficients are made between the RANS results and existing LES and DNS results. There is a significant degree of variability in the performance of the various RANS models across all comparison metrics. However, the Reynolds stress model demonstrated the best accuracy in terms of the mean velocity profile as well as drag partition across the range of packing densities.

© 2021, ASME. Originally published in ASME 2021 Fluids Engineering Division Summer Meeting.

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Work Title Modeling of Cube Array Roughness: RANS, LES, and DNS
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Open Access
Creators
  1. Samuel Altland
  2. Haosen H. A. Xu
  3. Xiang I. A. Yang
  4. Robert Kunz
License CC BY 4.0 (Attribution)
Work Type Article
Publisher
  1. American Society of Mechanical Engineers
Publication Date August 10, 2021
Publisher Identifier (DOI)
  1. 10.1115/fedsm2021-65494
Source
  1. Volume 3: Fluid Mechanics; Micro and Nano Fluid Dynamics; Multiphase Flow
Deposited April 25, 2022

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  • Created
  • Added Sam_Altland_Cube_JFE_Manuscript_Feb7-1.pdf
  • Added Creator Samuel Altland
  • Added Creator Haosen H. A. Xu
  • Added Creator Xiang I. A. Yang
  • Added Creator Robert Kunz
  • Published
  • Updated Description Show Changes
    Description
    • <jats:title>Abstract</jats:title>
    • <jats:p>Flow over arrays of cubes is an extensively studied model problem for rough wall turbulent boundary layers. While considerable research has been performed in computationally investigating these topologies using DNS and LES, the ability of sublayer-resolved RANS to predict the bulk flow phenomena of these systems is relatively unexplored, especially at low and high packing densities. Here, RANS simulations are conducted on six different packing densities of cubes in aligned and staggered configurations. The packing densities investigated span from what would classically be defined as isolated, up to those in the d-type roughness regime, filling in the gap in the present literature. Three different sublayer-resolved turbulence closure models were tested for each case; a low Reynolds number k-ε model, the Menter k-ω SST model, and a full Reynolds stress model. Comparisons of the velocity fields, secondary flow features, and drag coefficients are made between the RANS results and existing LES and DNS results. There is a significant degree of variability in the performance of the various RANS models across all comparison metrics. However, the Reynolds stress model demonstrated the best accuracy in terms of the mean velocity profile as well as drag partition across the range of packing densities.</jats:p>
    • Flow over arrays of cubes is an extensively studied model problem for rough wall turbulent boundary layers. While considerable research has been performed in computationally investigating these topologies using DNS and LES, the ability of sublayer-resolved RANS to predict the bulk flow phenomena of these systems is relatively unexplored, especially at low and high packing densities. Here, RANS simulations are conducted on six different packing densities of cubes in aligned and staggered configurations. The packing densities investigated span from what would classically be defined as isolated, up to those in the d-type roughness regime, filling in the gap in the present literature. Three different sublayer-resolved turbulence closure models were tested for each case; a low Reynolds number k-ε model, the Menter k-ω SST model, and a full Reynolds stress model. Comparisons of the velocity fields, secondary flow features, and drag coefficients are made between the RANS results and existing LES and DNS results. There is a significant degree of variability in the performance of the various RANS models across all comparison metrics. However, the Reynolds stress model demonstrated the best accuracy in terms of the mean velocity profile as well as drag partition across the range of packing densities.
  • Updated Work Title Show Changes
    Work Title
    • MODELING OF CUBE ARRAY ROUGHNESS; RANS, LES AND DNS
    • Modeling of Cube Array Roughness: RANS, LES, and DNS
  • Updated