Modeling of near-surface flows over an aeolian relief

Abstract

As a result of interaction of an air flow with the elements of an aeolian relief, the character of the flow changes. It affects both the conditions of dust blowing from the surface and the surface shape itself. A model is developed for the formation of the windward slope under the influence of wind. It makes it possible to estimate the dynamic speed when moving up the windward slope on the basis of data on height and movement of the dunes. The coefficient of linear change in the dynamic velocity and its decrease with increasing structure are obtained. This property is probably due to a change in the nature of the flow and circulation at the surface. To study such problems, dome methods are applied to simulate the air flow near a complex 3D surface using the open OpenFOAM package with a 4-level spatial grid. A technology is also proposed for converting the digital terrain data into a format understandable to mathematical packages for modelling of air flow around a 3D object. Based on the simulation results, the coefficient of linear change in the dynamic velocity for aeolian structures with a height of about 100 m has been calculated, which generally corresponds to values obtained from theoretical estimates and real data on changes in height and movement of dunes.