The craters formed by the impact of steel balls with a loose sand bed are experimentally studied. Both crater size and morphology depend strongly on the impact angle. Two scaling laws, corresponding to length and width respectively, are proposed.

The profiles of particle concentration in saltation layer versus height are calculated, by the motion equations for a saltating grain in conjunction with different probability distribution functions of the vertical liftoff velocities of grains and an empirical expression of wind velocity. The numerical results demonstrated that the stratification phenomenon exists in the particle concentration profiles and showed increasing, saturating and decreasing features, respectively, when the probability distribution functions of liftoff velocities adopted in the calculation are similar to a normal distribution or a two-parameter gamma distribution. When the distribution function of liftoff velocities is taken as an exponential form, the profile of particle concentration decreases monotonically. A numerical simulation of mass flux of grains, performed by the model suggested in this paper, is in reasonable accordance with the measured data.

土壤风蚀以及沙尘暴是人类面临的重大自然环境灾害之一，它直接关系着人类的生存环境和生活质量。许多国家和政府以及科学家们对此一直十分关注并开展了大量研究。由于大气和地表条件的多样性以及地表沙粒的运动与风场作用的相互耦合，导致风沙运动问题研究的复杂性。除此之外，伴随着对风沙运动机理的研究和对沙尘暴的观测，人们发现在风沙跃移运动和沙尘暴中的沙粒带有电荷并形成风沙电场。沙粒的运动不仅导致沙粒带电和风沙电场形成，而且也直接受到沙粒带电和风沙电场的影响。为了弄清风沙电的起因以及揭示其影响规律，研究人员对此进行了野外观测、实验室测量和理论推测等。本文将就这一问题重点介绍有关风沙运动中沙粒带电的机理、风沙电场分布规律、沙粒带电对风沙运动的微宏观物理量以及沙尘暴中沙粒带电对电磁波散射的影响等方面的实验和理论研究的基本概况和进展以及作者等人在此方面的研究工作。主要包含内容有：沙粒带电及其电场的基本实验测量，沙粒带电对风沙运动的影响，沙尘暴对电磁波衰减的影响研究以及有关风沙起电的机理研究等。同时，对这一研究领域中目前关注与存在的主要问题给予评述。

This article presents a measurement of electrification generated by wind-blown sands in a field wind tunnel and a numerical methodology to simulate the effect of electrification on the sand saltation movement after the mutual couple interaction between the sand movement and the wind flow is taken into account. The measured data of electric charge on the "uniform" sands in the wind-tunnel tests show that the sign of electric charge, either negative or positive, is mainly dependent on the diameter size of sand particles, i.e., negative charge is gained when the diameter is smaller than 250 mm and positive charge is obtained if the diameter is larger than 500 mm, and that for both "uniform" and mixed sands, the average charge-to-mass ratio decreases with increasing the wind velocity, and increases with height from sand bed. Meanwhile, the measurement of electric field in wind-sand cloud related to the electric charge displays that the magnitude of electric field increases generally as the wind velocity and the height increase, and the direction of the field is always upwardly vertical to the Earth’s surface, which is opposite to that of the fair-weather field. In order to exhibit the effect of electrification on sand saltation movement, a theoretical model by considering the mutual coupling interaction between wind flow and sand movement is proposed after the electric force exerted on the moving sands is considered. Through solving the nonlinear coupling dynamic equations by a proposed program, the effect of electrification on sand saltation motion, e.g., trajectory, is discussed quantitatively. After that, its effect on wind-sand transport flux, sand ejecta flux, and wind profile is also displayed. The results show that the prediction for the Bagnold's kink is good agreement with the measurement in literature.

A theoretical study of bending and buckling of ferroelastic plates in the presence of magnetic fields is carried out based on the model that takes into account the nonlinear field-structure interaction. The resultant force system derived from the interaction between magnetic fields and ferromagnetic materials is composed of the body force only. Using this model, the bending and buckling problems of a cantilevered ferromagnetic plate and simply supported rectangular plates in transverse and oblique magnetic fields are investigated with the aid of a numerical approach. Numerical results reveal some interesting features of magnetoelastic bending and buckling phenomena due to the nonlinear nature of the field-structure interaction.