Wind speed-up process on the windward slope of dunes in dune fields

Wind speed-up is a key physical factor affecting the transportation of windblown sand on the windward slope of a sand dune. It contributes to the understanding of dune morphology, evolution of dune field and dunes’ migration. In this study, a computational model is proposed to calculate the wind speed-up factor on the windward slope of sand dunes in a dune field. This model not only reflects the influence of neighboring dunes, but also incorporates the effect of incoming wind speed, sand diameter and thickness of sand supply which have been little considered by previous studies. The computational complexity of our model is much lower than that of the Jackson–Hunt theory and the Computational Fluid Dynamics. Based on the wind speed-up model, we investigate the probability density function of wind speed-up factor in a dune field, and give an empirical expression of wind speed-up factor, which provides a basis for accurate prediction of wind speed on the windward slope of a sand dune in a real dune field.

► A computational model is proposed to calculate the wind speed-up factor. ► The model can reflect the influence of neighboring dunes, wind speed and so on. ► The computational complexity of the model is much lower than that of other methods. ► An empirical expression of wind speed-up factor was given.