Seminarium Zakładu Mechaniki i Fizyki Płynów Spreading fronts and fluctuations in sedimentation dr Laurence Bergougnoux (IUSTI, Marseille, France) środa, 4 czerwca 2003

While the average velocity of a suspension of spheres sedimenting in a viscous fluid can be successfully predicted theoretically, the problem of velocity fluctuations is still unresolved. We examined by laboratory experiments how the sedimentation front spreads and how this affects the velocity fluctuations. Experiments were undertaken at very low Reynolds number Re < 10^-4 and volume fraction around 0.3 %. Two types of experimental measurements were performed. The spreading of the sedimentation front was measured using the attenuation of light through the suspension. The particle velocities were measured using particle image velocimetry (PIV).