Unsteady forces on a circular cylinder at critical Reynolds numbers

Abstract

The analysis of the resulting spectrum showed the footprint of Kelvin-Helmholtz instabilities in the whole range. It is found that the ratio of these instabilities frequency to the primary vortex shedding frequency matches quite well the scaling proposed by Prasad and Williamson (f KH /f vs ∝ Re 0.67 ).

The intermittent nature of the laminar separation bubble on a cylinder in uniform flow

“…Similar observations were made by Lehmkuhl et al (2014). Singh and Mittal (2005) investigated this regime by carrying out two-dimensional simulations.…”

“…The LSB lies in the region between the laminar separation and turbulent attachment of the flow. The appearance of the LSB beyond the critical regime has also been reported by Tani (1964) and Lehmkuhl et al (2014). An interesting observation from Figure 5 is that the imprint of the LSB is weak at the onset of the critical regime and becomes stronger with increase in Re.…”

“…In an experimental study, Miau et al (2011) found that the development of LSB causes the vortex shedding frequency to fluctuate with large uncertainty. Lehmkuhl et al (2014) performed three-dimensional large eddy simulations with high span wise grid resolution. They observed asymmetric reattachment in the critical regime.…”

Asymmetric wake of a horizontal cylinder in close proximity to a solid boundary for Reynolds numbers in the subcritical turbulence regime

“…With increasing Reynolds number greater than 5,000 the wake typology remains unchanged up to a Reynolds number of 2•10 5 , which marks the beginning of the supercritical flow regime where a significant change in the flow separation reduces the drag coefficient from values ranging from 1.0-1.4 to between 0.2-0.4 [10][11][12] . A detailed summary of the wake dynamics dependency on Reynolds number is given in Williamson 13 and Sumner 14 .…”

On the extension of LES methods from incompressible to compressible turbulent flows with application to turbulent channel flow

“…This models have been tested in several cases, such as the flow over a NACA0012 airfoil [2] [3] and a circular cylinder [4]. The compressible solver implemented in TermoFluids uses a kinetic-energy preserving secondorder spatial scheme, carefully hybridized with a low-order dissipative upwind scheme in order to stabilize the method in the presence of flow discontinuities.…”