TY - JOUR

T1 - Turbulent particle flux to a perfectly absorbing surface

AU - Mann, J.

AU - Ott, Søren

AU - Pecseli, H.L.

AU - Trulsen, J.

PY - 2005

Y1 - 2005

N2 - The feasibility of an experimental method for investigations of the particle flux to an absorbing surface in turbulent flows is demonstrated in a Lagrangian as well as an Eulerian representation. A laboratory experiment is carried out, where an approximately homogeneous and isotropic turbulent flow is generated by two moving grids. The simultaneous trajectories of many small approximately neutrally buoyant polystyrene particles are followed in time. In a Lagrangian analysis, we select one of these as the centre of a ‘sphere of interception’, and obtain estimates for the time variation of the statistical average of the inward particle flux through the surface of this moving sphere. The variation of the flux with the radius in the sphere of interception, as well as the variation with basic flow parameters is described well by a simple model, in particular for radii smaller than a characteristic length scale for the turbulence. The Eulerian counterpart of the problem is analysed as well, and the two results compared. Applications of the problem to, for instance, the question of the feeding rate of micro-organisms in turbulent marine environments are pointed out.

AB - The feasibility of an experimental method for investigations of the particle flux to an absorbing surface in turbulent flows is demonstrated in a Lagrangian as well as an Eulerian representation. A laboratory experiment is carried out, where an approximately homogeneous and isotropic turbulent flow is generated by two moving grids. The simultaneous trajectories of many small approximately neutrally buoyant polystyrene particles are followed in time. In a Lagrangian analysis, we select one of these as the centre of a ‘sphere of interception’, and obtain estimates for the time variation of the statistical average of the inward particle flux through the surface of this moving sphere. The variation of the flux with the radius in the sphere of interception, as well as the variation with basic flow parameters is described well by a simple model, in particular for radii smaller than a characteristic length scale for the turbulence. The Eulerian counterpart of the problem is analysed as well, and the two results compared. Applications of the problem to, for instance, the question of the feeding rate of micro-organisms in turbulent marine environments are pointed out.

KW - 1-E vind

U2 - 10.1017/S0022112005004672

DO - 10.1017/S0022112005004672

M3 - Journal article

VL - 534

SP - 1

EP - 21

JO - Journal of Fluid Mechanics

JF - Journal of Fluid Mechanics

SN - 0022-1120

ER -