Fluid velocity fluctuations in a collision of a sphere with a wall

J. Rafael Pacheco*, Angel Ruiz-Angulo, Roberto Zenit, Roberto Verzicco

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

We report on the results of a combined experimental and numerical study on the fluid motion generated by the controlled approach and arrest of a solid sphere moving towards a solid wall at moderate Reynolds number. The experiments are performed in a small tank filled with water for a range of Reynolds numbers for which the flow remains axisymmetric. The fluid agitation of the fluid related to the kinetic energy is obtained as function of time in the experiment in a volume located around the impact point. The same quantities are obtained from the numerical simulations for the same volume of integration as in the experiments and also for the entire volume of the container. As shown in previous studies, this flow is characterized by a vortex ring, initially in the wake of the sphere, that spreads radially along the wall, generating secondary vorticity of opposite sign at the sphere surface and wall. It is also observed that before the impact, the kinetic energy increases sharply for a small period of time and then decreases gradually as the fluid motion dies out. The measure of the relative agitation of the collision is found to increase weakly with the Reynolds number Re. The close agreement between the numerics and experiments is indicative of the robustness of the results. These results may be useful in light of a potential modelling of particle-laden flows. Movies illustrating the spatio-temporal dynamics are provided with the online version of this paper.

Original languageEnglish
Article number063301
JournalPhysics of Fluids
Volume23
Issue number6
DOIs
Publication statusPublished - 3 Jun 2011

Bibliographical note

Funding Information:
The comments of the anonymous Referees have greatly influenced the final version of this paper and are very much appreciated. This work was partially supported by the National Science Foundation Grant No. CBET-0608850 and by National Autonomous University of Mexico through its PAPIIT-DGAPA program (Grant No. IN 103900). A.R.-A. acknowledges the PROBETEL and IIM-UNAM for their scholarship program support. The authors acknowledge Texas Advanced Computing Center (TACC) at the University of Texas at Austin and Ira A. Fulton High Performance Computing Initiative at Arizona State University, both members of the NSF-funded Teragrid, for providing HPC and visualization resources.

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