Publications de Kasper van der Vaart

Breaking size-segregation waves and mobility feedback in dense granular avalanches

Through experiments and discrete particle method (DPM) simulations we present evidence for the existence of a recirculating structure, that exists near the front of dense granular avalanches, and is known as a breaking size-segregation (BSS) wave. This is ...

2018

Segregation of large particles in dense granular flows suggests a granular Saffman effect

Christophe Ancey, Kasper van der Vaart

We report on the scaling between the lift force and the velocity lag experienced by a single particle of different size in a monodisperse dense granular chute flow. The similarity of this scaling to the Saffman lift force in (micro-) fluids, suggests an in ...

2018

Particle Size Segregation in Dense Granular Flows

Kasper van der Vaart

Flows of granular materials widely occur in many industrial and natural environments. Particle-size segregation---the separation of grains of different sizes during flow---plays a crucial role in the behaviour of such flows. In spite of considerable effort ...

EPFL2016

Asymmetric breaking size-segregation waves in dense granular free-surface flows

Christophe Ancey, Kasper van der Vaart

Debris and pyroclastic flows often have bouldery flow fronts, which act as a natural dam resisting further advance. Counter intuitively, these resistive fronts can lead to enhanced run-out, because they can be shouldered aside to form static levees that se ...

Cambridge University Press2016

An Underlying Asymmetry within Particle-size Segregation

Christophe Ancey, Nicolas Andreini, Gaël Epely Chauvin, Kasper van der Vaart

We experimentally study particle scale dynamics during segregation of a bidisperse mixture under oscillatory shear. Large and small particles display an underlying asymmetry that is dependent on the local particle concentration, with small particles segreg ...

American Physical Society2015