ANALYSIS OF PARTICLE DEPOSITION FROM TURBULENT LIQUID-FLOW ONTO SMOOTH CHANNEL WALLS

International audienceIn this study, we analyse the motion of hydrosol particles in the near-wall shear layer of a turbulent channel flow. The liquid flow-field is described using the kinematic model proposed by Fan and Ahmadi (1995) combined with Lagrangian particle tracking. Numerical simulations were performed for friction velocity ranging from 1.5 mm. to 15 mm. , particle diameter from 5 to 50, particle to liquid density ratio from 1 to 1.4 and wall roughness height from to. The results show that the inertia effects are very weak. For nonbuoyant particles, direct interception is the main deposition mechanism and a law giving the deposition velocity as a function of the different parameters is proposed. For buoyant particles the deposition is controlled by sedimentation for the smallest values of friction velocity. When friction velocity increases, the direct interception contribution increases as well, and may prevail on sedimentation