Flow around a 5:1 rectangular cylinder: Effects of upstream-edge rounding

The Turbulent Flow over the BARC Rectangular Cylinder: A DNS Study

“…This frequency range is not entirely in agreement with Cimarelli et al (2018b), where the range is reportedly f ≈ 0.9−1.8. Similar results have been found also at larger Reynolds numbers; Rocchio et al (2020) report frequencies in the range of f ≈ 0.75−1.52 for x < −0.5 and f ≈ 0.375 for x ≈ 0. Point e is downstream the reattachment point, and the flow there is fully turbulent.…”

“…Overall, P 11 contributes to P k more than P 22 almost everywhere in the domain, as seen in Fig. 11; this is true also for x = − 2.5, unlike what found at larger Re in Rocchio et al (2020), where a larger contribution from P 22,b is reported. In Cimarelli et al (2019) negative production is linked to the interaction between uv and the mean streamwise and vertical shears ∂U /∂ y and ∂ V /∂ x.…”

“…This suggests that at this Reynolds number the wake still influences the leadingedge region, as it happens at much lower Re (Hourigan et al 2001). The vortex-shedding frequency has been detected at these upstream sections also by Moore et al (2019) for Re = 13,400, but not by Rocchio et al (2020) at Re = 40,000; this suggests that the influence of the vortex shedding from the trailing edge on the first part of the shear layer gradually fades away as Re increases. Moving along the shear layer, a higher dominant frequency f ≈ 1.3 emerges, associated to the amplification of the velocity fluctuations in the shear layer (Cimarelli et al 2018b) owing to the Kelvin-Helmotz instability (Moore et al 2019).…”

“…Very recently, Cimarelli et al (2019), Moore et al (2019) and Rocchio et al (2020) presented and discussed the production term in the equation for the turbulent kinetic energy, with the latter two studies focusing on the region close to the upstream corners. Hence, before presenting the Reynolds stresses, we start with Fig.…”

“…Similarly Mariotti et al (2017) presented a stochastic analysis of the sensitivity of LES results to grid resolution and details of the model filter, finding that a finer grid translates into a significantly smaller primary vortex. More recently, Rocchio et al (2020) performed a sensitivity analysis of LES simulations of the BARC flow to the rounding of the leading-edge corners, to the aim of explaining the discrepancy between well-resolved numerical simulations and experiments. They observed that introducing a very small radius of curvature is sufficient to enhance the agreement between numerical and experimental data.…”