EPTT 2020

12th Spring School on Transition and Turbulence

NUMERICAL SIMULATION OF BARCHAN DUNES IN A TURBULENT CHANNEL FLOW

Submission Author: Carlos Azael Alvarez , SP
Co-Authors: Carlos Azael Alvarez, Erick de Moraes Franklin
Presenter: Carlos Azael Alvarez

doi://10.26678/ABCM.EPTT2020.EPT20-0118

 

Abstract

Barchan dunes are characterized by a crescentic shape and can be found in rivers, terrestrial deserts and other planetary environments. These bedforms present different scales according to the environment they are in, their length scale varying from the decimeter under water to the kilometer on Mars. Depending on the nature of the entraining fluid the transport of grains presents significant differences so that the growth of this kind of dunes rests to be fully understood. Aquatic barchans have smaller length and time scales, so they are the ideal object to characterize the growth of these bedforms. In this work, we computed the bed evolution by using the computational fluid dynamics - discrete element method, where we coupled the discrete element method with large eddy simulation. We obtained the resultant force acting on each grain, which has not been previously measured nor computed. Our results show that the present method is appropriate for numerical computations of bedforms, opening new possibilities for accessing data that are not available from current experiments. This paper is based on C. A. Alvarez and E. M. Franklin, Phys. Rev. E 101, 012905 (2020) and reproduces many of its parts.

Keywords

grains, bed-load, barchan dunes, Large Eddy Simulation, Discrete element method

 

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