Direct numerical simulation of pattern formation in subaqueous sediment

Abstract

We present results of direct numerical simulation of incompressible fluid flow over a thick bed of mobile, spherically-shaped particles. The algorithm is based upon the immersed boundary technique for fluid-solid coupling and uses a soft-sphere model for the solid-solid contact. Two parameter points in the laminar flow regime are chosen, leading to the emergence of sediment patterns classified as `small dunes', while one case under turbulent flow conditions leads to `vortex dunes' with significant flow separation on the lee side. Wavelength, amplitude and propagation speed of the patterns extracted from the spanwise-averaged fluid-bed interface are found to be consistent with available experimental data. The particle transport rates are well represented by available empirical models for flow over a plane sediment bed in both the laminar and the turbulent regimes.

accepted for publication in J. Fluid Mech. 2014, more data at http://www.ifh.kit.edu/dns_data/

References in corpus (2)

• Interface-resolved direct numerical simulation of the erosion of a sediment bed sheared by laminar channel flow
• DNS of vertical plane channel flow with finite-size particles: Voronoi analysis, acceleration statistics and particle-conditioned averaging

Cited by in corpus (7)

• Interface-resolved direct numerical simulations of sediment transport in a turbulent oscillatory boundary layer
• Direct numerical simulation of open-channel flow over a fully-rough wall at moderate relative submergence
• Sediment transport under oscillatory flows
• Shape evolution of numerically obtained subaqueous barchan dunes
• Force distribution within a barchan dune
• Grain-scale computations of barchan dunes
• On the scaling of the instability of a flat sediment bed with respect to ripple-like patterns