科研之友
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摘要
We predict the threshold for continuing saltation of spheres in a turbulent fluid that explicitly accounts for the influence of fluid drag, lubrication forces, bed roughness, and interparticle cohesion. This reduces the need for the fitting parameters employed in existing formulations. The theory is based on a highly idealized model of steady saltation as a collection of particles that follow the same average, periodic trajectorya succession of identical jumps, collisions with the bed, and rebounds from it. The saltation threshold is first derived in the limit of large particle inertia and, then, extended to infer results when the viscous forces of the fluid and interparticle cohesion are not negligible. The theory is successfully compared with existing discrete element simulations of spheres interacting with a Reynolds-averaged turbulent fluid and with wind tunnel experiments in a range of particle-to-fluid density ratios and particle Reynolds numbers for saltation in terrestrial and extraterrestrial conditions.
- 出版日期2017-7
