Rotation of anisotropic particles in Rayleigh–Bénard turbulence

Abstract

Abstract

Long non-axisymmetric fibres in turbulent channel flow

“…The same observation holds for the mean square tumbling rate measured in the near-wall region of Rayleigh–Bénard experiments (Jiang et al. 2020). We mention a possible error of bias here: since the time scale of the flow varies from the wall to the centre of the channel, the temporal filter used to process the data (see § 3.4) could underestimate – wall region – or overestimate – central region – the magnitudes of .…”

“…2012; Jiang et al. 2020) are also shown (symbols) as well as results for straight ellipsoids (Jeffery orbits, obtained with the Hinch & Leal (1979) model with ; dashed line).…”

“…2012; Jiang et al. 2020), as shown in figure 18( a ). However, we remark here that fibres belonging to the first curvature class cannot be strictly considered as straight.…”

“…2020; Jiang et al. 2020). For long and neutrally buoyant straight rods in HIT conditions, the magnitude of mean squared tumbling rate is observed to be approximately 0.1 (Parsa et al.…”

“…Following the same approach, a modified scaling for the tumbling rate of rod-like particles was provided in subsequent works by Bordoloi & Variano (2017), Bounoua, Bouchet & Verhille (2018), Kuperman, Sabban & van Hout (2019) and Bordoloi, Variano & Verhille (2020). Recently, Jiang, Calzavarini & Sun (2020) investigated the rotation of oblate and prolate spheroids in a Rayleigh–Bénard flow. They showed that the trend of the tumbling rate as a function of the aspect ratio, due to shear, has a peak for weakly oblate spheroids, in contrast with the monotonic universal trend previously reported for HIT configuration.…”