Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions

Beitrag in einer Fachzeitschrift
(Originalarbeit)


Details zur Publikation

Autorinnen und Autoren: Rodríguez Agudo J, Han J, Park J, Kwon S, Loekman S, Luzi G, Lindenberger C, Delgado A, Wierschem A
Zeitschrift: Journal of Visualized Experiments
Verlag: JOURNAL OF VISUALIZED EXPERIMENTS
Jahr der Veröffentlichung: 2018
Heftnummer: 132
ISSN: 1940-087X


Abstract

Two different experimental methods for determining the threshold of particle motion as a function of geometrical properties of the bed from laminar to turbulent flow conditions are presented. For that purpose, the incipient motion of a single bead is studied on regular substrates that consist of a monolayer of fixed spheres of uniform size that are regularly arranged in triangular and quadratic symmetries. The threshold is characterized by the critical Shields number. The criterion for the onset of motion is defined as the displacement from the original equilibrium position to the neighboring one. The displacement and the mode of motion are identified with an imaging system. The laminar flow is induced using a rotational rheometer with a parallel disk configuration. The shear Reynolds number remains below 1. The turbulent flow is induced in a low-speed wind tunnel with open jet test section. The air velocity is regulated with a frequency converter on the blower fan. The velocity profile is measured with a hot wire probe connected to a hot film anemometer. The shear Reynolds number ranges between 40 and 150. The logarithmic velocity law and the modified wall law presented by Rotta are used to infer the shear velocity from the experimental data. The latter is of special interest when the mobile bead is partially exposed to the turbulent flow in the so-called hydraulically transitional flow regime. The shear stress is estimated at onset of motion. Some illustrative results showing the strong impact of the angle of repose, and the exposure of the bead to shear flow are represented in both regimes.


FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Delgado, Antonio Prof. Dr.-Ing.
Lehrstuhl für Strömungsmechanik
Lindenberger, Christoph Prof. Dr.-Ing.
Department Chemie- und Bioingenieurwesen
Loekman, Soebiakto
Lehrstuhl für Chemische Reaktionstechnik
Luzi, Giovanni
Department Chemie- und Bioingenieurwesen
Park, Jinyoung
Lehrstuhl für Strömungsmechanik
Rodríguez Agudo, José
Department Chemie- und Bioingenieurwesen
Wierschem, Andreas Prof. Dr.
Professur für Hochdruckthermofluiddynamik und Rheologie


Zitierweisen

APA:
Rodríguez Agudo, J., Han, J., Park, J., Kwon, S., Loekman, S., Luzi, G.,... Wierschem, A. (2018). Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions. Journal of Visualized Experiments, 132. https://dx.doi.org/10.3791/57238

MLA:
Rodríguez Agudo, José, et al. "Visually Based Characterization of the Incipient Particle Motion in Regular Substrates: From Laminar to Turbulent Conditions." Journal of Visualized Experiments 132 (2018).

BibTeX: 

Zuletzt aktualisiert 2019-23-07 um 07:54