LES-based study of the roughness effects on the wake of a circular cylinder from subcritical to transcritical Reynolds numbers
Visualitza/Obre
Cita com:
hdl:2117/119394
Tipus de documentArticle
Data publicació2017-10-27
Condicions d'accésAccés obert
Tots els drets reservats. Aquesta obra està protegida pels drets de propietat intel·lectual i
industrial corresponents. Sense perjudici de les exempcions legals existents, queda prohibida la seva
reproducció, distribució, comunicació pública o transformació sense l'autorització del titular dels drets
Abstract
This paper investigates the effects of surface roughness on the flow past a circular cylinder at subcritical to transcritical Reynolds numbers. Large eddy simulations of the flow for sand grain roughness of size k/D = 0.02 are performed (D is the cylinder diameter). Results show that surface roughness triggers the transition to turbulence in the boundary layer at all Reynolds numbers, thus leading to an early separation caused by the increased momentum deficit, especially at transcritical Reynolds numbers. Even at subcritical Reynolds numbers, boundary layer instabilities are triggered in the roughness sublayer and eventually lead to the transition to turbulence. The early separation at transcritical Reynolds numbers leads to a wake topology similar to that of the subcritical regime, resulting in an increased drag coefficient and lower Strouhal number. Turbulent statistics in the wake are also affected by roughness; the Reynolds stresses are larger due to the increased turbulent kinetic energy production in the boundary layer and separated shear layers close to the cylinder shoulders.
Descripció
This is a copy of the author 's final draft version of an article published in the journal Flow turbulence and combustion.
CitacióRodriguez, I., Lehmkuhl, O., Piomelli, U., Chiva, J., Borrell, R., Oliva, A. LES-based study of the roughness effects on the wake of a circular cylinder from subcritical to transcritical Reynolds numbers. "Flow turbulence and combustion", 27 Octubre 2017, vol. 99, núm. 3-4, p. 729-763.
ISSN1386-6184
Versió de l'editorhttps://link.springer.com/article/10.1007%2Fs10494-017-9866-2
Fitxers | Descripció | Mida | Format | Visualitza |
---|---|---|---|---|
Article_prp.pdf | 6,279Mb | Visualitza/Obre |