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Study of irregular roughness in minimal channels

Yang, Jiasheng ORCID iD icon; Stroh, Alexander; Jakirlic, Suad; Frohnapfel, Bettina; Forooghi, Pourya


Direct numerical simulation (DNS) is carried out to study turbulent flow over irregular rough surfaces in periodic minimal channels. A passive scalar transport equation is solved to study heat transfer over rough surfaces with the Prandtl number $Pr$= 0.7. The generation of irregular roughness is based on a mathematical randomization algorithm, in which the power spectrum (PS) of the roughness height function along with its probability density function (PDF) can be directly prescribed. The hydrodynamic and thermal properties of the roughness, particularly the roughness function ($\Delta U^+$) as well as the temperature profile offset ($\Delta \Theta^+$), are compared with those obtained from a full span DNS for 6 types of roughness topographies with systematically varied PDF and PS configurations at Re$\tau \approx$ 500. The comparison confirms the ability of the minimal channel approach to perform characterization of irregular rough surfaces providing excellent agreement (within 5$\%$) in $\Delta U^+$ and $\Delta \Theta^+$ across various types of roughness topographies. Results also indicate that random realizations of roughness, with a fixed PS and PDF, translate to similar prediction with a narrow scatter. ... mehr

Postprint §
DOI: 10.5445/IR/1000140429
Veröffentlicht am 01.10.2022
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Strömungsmechanik (ISTM)
Publikationstyp Proceedingsbeitrag
Publikationsmonat/-jahr 09.2021
Sprache Englisch
Identifikator KITopen-ID: 1000140429
Erschienen in ETMM 13, International symposium on engineering, turbulence, modelling and measurement, 15.09.-17.09.2021
Veranstaltung 13th International ERCOFTAC symposium on engineering, turbulence, modelling and measurements (ETMM 2021), Rhodos, Griechenland, 15.09.2021 – 17.09.2021
Externe Relationen ResearchGate
Schlagwörter Minimal channel, irregular roughness, DNS, heat transfer
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