Fluctuating lift on a circular cylinder: review and new measurements

Low-frequency unsteadiness in the vortex formation region of a circular cylinder

“…Norberg 6 in his work, suggested that there is a change in the wake configuration at Re = 5000. This transition was later confirmed by Prasad and 12 Williamson, 41 while Norberg 39 attributed this change to a transition between a high-and low-quality vortex shedding mode. The results here presented suggest that at Re = 3900 both modes coexist and the wake is oscillating between them at a very low-frequency, and as has been shown this is the cause of the large scattering in the experimental and numerical results observed up until now.…”

Desenvolvimento da modelagem de turbulência e interação fluido-estrutura para as vibrações induzidas por vórtices de cilindro rígido.

“…It has also been discussed that the experimental results, especially for Re = 1, 000 − 100, 000, displays a strong three-dimensional character, from which one expects low regularity and lower amplitude of the lift traces and, hence, lower RMS value. The same spread behavior for the lift RMS is observed in different calculations and even experiments (NORBERG, 2003) indicating very high uncertainty in this quantity. .29 shows the vorticity distributions for the turbulent calculations.…”

“….20 presents the Strouhal frequencies (in nondimensional form, Strouhal number), calculated by means of the peak-energy frequency of the power spectral density obtained from the lift force. There is a fair agreement with the experimental trend from Norberg (2003). Figure 6.21 shows an example of time traces of the force coefficients for Re = 100, in which high regularity is seen and a prominent peak energy is found.…”

Suppression of vortex-induced vibration of a circular cylinder with fixed and rotating control cylinders.

“…The value ofĈ L , its correctionĉ L and the regression proposed by Norberg (2003) are shown in Based on the data presented and discussed, it is estimated that the results for the plain cylinder are in good agreement with data in the literature and will be a good reference for the results obtained with suppressors models, described in subsequent sections.…”

“…So it is necessary to distinguish the two coe cients, whereĈ L is the sectional RMS lift coe cient. Norberg (2003) analyzed several experimental and numerical results obtained under di erent conditions.…”