Skip to Main content Skip to Navigation
Journal articles

Physical interpretation of probability density functions of bubble-induced agitation

Abstract : A stochastic model is presented for the probability density function (p.d.f.) of the liquid velocity fluctuations generated by high-Reynolds-number rising bubbles. It considers three elementary sources of fluctuations: the potential flow disturbance around each bubble; the average bubble wakes, which are assumed to decay exponentially; and the turbulent agitation resulting from the flow instability, which is assumed to be isotropic, homogeneously distributed all over the flow and statistically independent of the two others. The model reproduces well and explains the characteristics of the experimental p.d.f.s: exponential tails, asymmetry of vertical fluctuations and evolution with the gas volume fraction. The model involves two a priori unknown parameters: the volume of the wake and the velocity scale of the turbulent agitation. Because some parts of the probability functions depend only on a single contribution, these two parameters can be uniquely and independently determined from experimental p.d.f.s. This defines an objective method to separate the various kinds of fluctuations and allows one to determine the contribution of each of them to the total agitation.
Complete list of metadatas

Cited literature [27 references]  Display  Hide  Download

https://hal.archives-ouvertes.fr/hal-01401237
Contributor : Open Archive Toulouse Archive Ouverte (oatao) <>
Submitted on : Wednesday, November 23, 2016 - 9:30:15 AM
Last modification on : Thursday, October 1, 2020 - 12:34:04 PM
Long-term archiving on: : Tuesday, March 21, 2017 - 12:25:33 PM

File

risso_16606.pdf
Files produced by the author(s)

Identifiers

Collections

Citation

Frédéric Risso. Physical interpretation of probability density functions of bubble-induced agitation. Journal of Fluid Mechanics, Cambridge University Press (CUP), 2016, vol. 809, pp. 240-263. ⟨10.1017/jfm.2016.690⟩. ⟨hal-01401237⟩

Share

Metrics

Record views

118

Files downloads

416