Erosion and Deposition of Particles in a Periodic Forced Flow - Selected Topics of Computational and Experimental Fluid Mechanics - page 426

Erosion and Deposition of Particles
in a Periodic Forced Flow

P. Villamil Sapien, I. Sánchez Calvo González, E.J. López-Sánchez
and G. Ruíz Chavarría

Abstract In this paper we present an experimental study of the erosion and
accumulation of particles produced by a periodic forced flow in two domains con-
nected by a channel. For this purpose a thin layer of sand is deposited on the bottom
of the channel and one of these domains. Then, a periodic flow rate is produced with
the aid of a block partially submerged in the fluid and subject to a sinusoidal vertical
motion. The evolution of the system was observed for thousands of periods. The aim
of this study is to model the particle transport in a tidal induced flow between an estu-
ary and the open sea. The erosion and accumulation zones observed in our study are
compared with results obtained in numerical simulations and observational works.

1 Introduction

Along the shore, the drag and deposition of sand or other particles are phenomena
that influence human activities. For instance, sand banks formed by turbulent currents
affect the near coast navigation. On the contrary, the same sand banks, if appropri-
ately situated, canmitigate the impact of a tsunami. Due to its importance, the particle
transport in shallow waters has been studied in the last decades. First, if we focus our
attention on fundamental studies, it is necessary to mention a work by Maxey and
Riley ( 1983 ). They deduced from first principles an equation of motion for spherical
particles inside a fluid, in which forces apart from drag and bouyancy are incorpo-
rated. From an experimental approach, Mordant et al. ( 2001 ) developed a method,
based on Doppler effect, for measuring the position and velocity of particles in a
turbulent flow. A monochromatic wave is scattered by the target particles, and then
a set of detectors record the scattered sound. The signal contains information about
the velocity and position of the particles. The particle transport has been investigated
when vortices are present (as in the flow we investigate). For instance, Angilella