In the present study, laminar and turbulent flow over a backward-facing step (BFSF) where a cylinder was placed immediately downstream of the step was investigated through numerical simulation using OpenFOAM. In laminar flow mean errors between numerical and literature experimental data for velocity profiles and reattachment lengths were lower than 8.1% and 18%, respectively. The cylinder significantly modified the structure of recirculating flow over the BFSF. In addition, the cylinder increased the skewness of the velocity profiles, and the location of the maximum velocity shifted towards the upper wall. In turbulent flow, the results from several RANS models (standard k-ɛ, RNG k-ɛ, standard k-ω, SST k-ω, and RSM (SSG)) were compared with literature experimental data. The average error in predicting reattachment length and velocity profiles ranged from 2.2% to 28.5% and from 7.8% to 14.5%, respectively. The most accurate model in predicting reattachment length and velocity profiles was the standard k-ɛ and SST k-ω models respectively. The cylinder modified flow structure and the distribution of turbulent kinetic energy, whose largest value was found downstream of a cylinder in the separated shear layer
Influence of a rigid cylinder on flow structure over a backward-facing step / Abdollahpour, Milad; Gualtieri, Paola; Gualtieri, Carlo. - (2022), pp. 3989-3998. (Intervento presentato al convegno 39° IAHR Wordl Congress From Snow to Sea tenutosi a Granada nel Giugno) [10.3850/IAHR-39WC2521711920221153].
Influence of a rigid cylinder on flow structure over a backward-facing step
Abdollahpour, Milad;Gualtieri, Paola;Gualtieri, Carlo
2022
Abstract
In the present study, laminar and turbulent flow over a backward-facing step (BFSF) where a cylinder was placed immediately downstream of the step was investigated through numerical simulation using OpenFOAM. In laminar flow mean errors between numerical and literature experimental data for velocity profiles and reattachment lengths were lower than 8.1% and 18%, respectively. The cylinder significantly modified the structure of recirculating flow over the BFSF. In addition, the cylinder increased the skewness of the velocity profiles, and the location of the maximum velocity shifted towards the upper wall. In turbulent flow, the results from several RANS models (standard k-ɛ, RNG k-ɛ, standard k-ω, SST k-ω, and RSM (SSG)) were compared with literature experimental data. The average error in predicting reattachment length and velocity profiles ranged from 2.2% to 28.5% and from 7.8% to 14.5%, respectively. The most accurate model in predicting reattachment length and velocity profiles was the standard k-ɛ and SST k-ω models respectively. The cylinder modified flow structure and the distribution of turbulent kinetic energy, whose largest value was found downstream of a cylinder in the separated shear layerFile | Dimensione | Formato | |
---|---|---|---|
Milad - IAHR 2022.pdf
accesso aperto
Licenza:
Dominio pubblico
Dimensione
1.1 MB
Formato
Adobe PDF
|
1.1 MB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.