Journal article

Direct numerical simulations of ripples in an oscillatory flow

Marco Mazzuoli, Aman G Kidanemariam, Markus Uhlmann

Journal of Fluid Mechanics | CAMBRIDGE UNIV PRESS | Published : 2019

Abstract

Sea ripples are small-scale bedforms which originate from the interaction of an oscillatory flow with an erodible sand bed. The phenomenon of sea ripple formation is investigated by means of direct numerical simulation in which the sediment bed is represented by a large number of fully resolved spherical grains (i.e.The flow around each individual particle is accounted for). Two sets of parameter values (differing in the amplitude and frequency of fluid oscillations, among other quantities) are adopted which are motivated by laboratory experiments on the formation of laminar rolling-grain ripples. The knowledge of the origin of ripples is presently enriched by insights and by providing fluid..

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Grants

Awarded by Office of Naval Research (U.S.)


Awarded by Deutsche Forschungsgemeinschaft (Germany)


Funding Acknowledgements

This study has been funded by the Office of Naval Research (U.S., under the research project no. 1000006450 -award no. N62909-17-1-2144) and by the Deutsche Forschungsgemeinschaft (Germany, project UH 242/4-2). We acknowledge the generous support from CINECA (Bologna, Italy) for the computational resources provided on FERMI under grant TEST SEA (PRACE 7th-call) and from the Steinbuch Centre for Computing (KIT, Karlsruhe) for the resources provided on ForHLR I under the grant DNSBESTSEA. The authors wish to thank P. Blondeaux and G. Vittori for fruitful discussions in particular concerning the interpretation of the bed evolution and the description of the experiments they carried out in Cambridge in 1988. The numerical investigations were performed during the time the second author (A.G.K.) was employed by the Institute for Hydromechanics, Karlsruhe Institute of Technology (KIT).