Numerical Modeling and Simulation of Wind Blown Sand Morphology under Complex Wind-Flow Field

Abstract

The flow field and the sand flow field constitutive equations are analyzed at first, then the different desert highway numerical models are established by considering the crossroad and by changing the road surface height and air stream flow field, then three kinds of different models with different complex air flow fields are made for simulating the sand ripple formation process by weak coupling of air and sand flow field, and finally the numerical simulations of these models are conducted and the affect process of sand morphology under complex air flow fields are discussed. The results show that under the uniform airflow field, the straight parallel ripple formed and the flared ripple formed in the middle region of the crossroad, and the wavelength of the ripples on the desert highway is bigger than that of the ripples around the road when the road height is higher than that of the sand surface height. Under the nonuniform complex airflow field, the complex curved ripples are formed, and some of the local area, where the whirlwind exits, no ripples are formed.

Analysis of significant risk factors for sand accumulation on desert expressways

“…Based on the findings, this study proposes a series of targeted strategies to effectively reduce the risk of road surface sand. It was found that wind speed is the most influential factor on road surface sand, which is consistent with the findings of Abdikerem et al [13]; the next most influential factors include the design of the median, height of the embankment, side slope ratio, and the angle between the wind direction and the roadway alignment, whereas the embankment width has a relatively small impact.…”

“…Scholars such as Yu et al [10], Cheng et al [11], and Gao et al [12] have studied road system selection and optimization through wind tunnel experiments. Abdikerem et al [13] established a model to determine sand movement patterns under different airflow conditions using the weak coupling relationship between airflow and sand flow fields.…”

Simulation of Sand Particles Flow Using a Weakly Compressible Smoothed Particle Hydrodynamics Method (WCSPH)

“…This method, called weakly compressible smoothed particle hydrodynamics (WCSPH), is developed by applying weakly compressible condition using a state equation. This approach is an imitation of real fluid, but with small sound speed (to the extent that time steps are not very small) and, on the contrary, large enough to guarantee Much number M⁓0.1; therefore, density variations are smaller than 0.01ρ .The most common state equation utilized in SPH simulation with standard of weakly compressible condition is in the following form [19]:…”

“…The formation of sand ripples on the desert areas have been studied by many researchers. Abdikerem et al [19] numerically studied the sand ripple formation process under uniform and nonuniform airflow and revealed that the nonuniform airflow creates the complex curved ripples. Aeolian sand ripples formation in desert highway was investigated by Ablimit et al [20] by using the weak coupling method.…”