Large Eddy Simulations (LES) are carried out to investigate on the mean flow in turbulent channel flows over irregular rough surfaces. Here the attention is focused to selectively investigate on the effect induced by crests or cavities of the roughness. The irregular shape is generated through the super-imposition of sinusoidal functions having random amplitude and four different wave-lengths. The irregular roughness profile is reproduced along the spanwise direction in order to obtain a 2D rough shape. The analysis of the mean velocity profiles shows that roughness crests induce higher effect in the outer-region whereas roughness cavities cause the highest effects in the inner-region with a reduced effect in the external region. The numerical simulations have been carried out at friction Reynolds number Reτ=395. Similar results have been found for the higher order statistics: turbulence intensities or shear stresses. The analysis of the Reynolds stress anisotropy tensor confirms the existence of specific roles of cavities and crests in the turbulence modulation. © 2019

De Marchis, M., Milici, B., & Napoli, E. (2019). Large eddy simulations on the effect of the irregular roughness shape on turbulent channel flows. INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW, 80, 1-15 [10.1016/j.ijheatfluidflow.2019.108494].

Large eddy simulations on the effect of the irregular roughness shape on turbulent channel flows

De Marchis, M;Milici, B;Napoli, Enrico
2019

Abstract

Large Eddy Simulations (LES) are carried out to investigate on the mean flow in turbulent channel flows over irregular rough surfaces. Here the attention is focused to selectively investigate on the effect induced by crests or cavities of the roughness. The irregular shape is generated through the super-imposition of sinusoidal functions having random amplitude and four different wave-lengths. The irregular roughness profile is reproduced along the spanwise direction in order to obtain a 2D rough shape. The analysis of the mean velocity profiles shows that roughness crests induce higher effect in the outer-region whereas roughness cavities cause the highest effects in the inner-region with a reduced effect in the external region. The numerical simulations have been carried out at friction Reynolds number Reτ=395. Similar results have been found for the higher order statistics: turbulence intensities or shear stresses. The analysis of the Reynolds stress anisotropy tensor confirms the existence of specific roles of cavities and crests in the turbulence modulation. © 2019
Settore ICAR/01 - Idraulica
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85073523085&doi=10.1016/j.ijheatfluidflow.2019.108494&partnerID=40&md5=5af041bde7013c457985b9c9cda7de56
De Marchis, M., Milici, B., & Napoli, E. (2019). Large eddy simulations on the effect of the irregular roughness shape on turbulent channel flows. INTERNATIONAL JOURNAL OF HEAT AND FLUID FLOW, 80, 1-15 [10.1016/j.ijheatfluidflow.2019.108494].
File in questo prodotto:
File Dimensione Formato  
Large_eddy_simulations_on_the_effect_of_the_irregular_roughness_shape_on_turbulent_channel_flows.pdf

Solo gestori archvio

Descrizione: Articolo principale
Tipologia: Versione Editoriale
Dimensione 7.56 MB
Formato Adobe PDF
7.56 MB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/10447/399493
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 8
  • ???jsp.display-item.citation.isi??? 7
social impact