In this paper, the sand break into highway problem in desert, which is caused by the sand flow blown by wind, is studied. The mathematical models are introduced by considering the fixed, semi-fixed and free sand desert fields based on the fluid dynamics and the sand particle dynamics. Different kinds of numerical models are made by changing the desert highway height, wind flow direction and its uniformity. The weak coupling method is used due to spatial relationships between air flow field and the sand flow field. Finally, by coupling the airflow field and sand flow field with desert highway, the numerical simulations of sand forming process on desert highway are conducted. The numerical results shown, that the wind blown sand breaks into highway easier when wind direction perpendicular highway and if the highway height higher than the range size of the sand surface the wind blown sand break into highway is more difficult.
In this study, to conduct numerical simulation of desert physiognomy forming process in
fixed, semi-fixed and free sand desert field by considering the sand flow process by wind, the
numerical model based on the hydrodynamics and sand grains kinemics are proposed. For analyze the
actual characteristic of sand movement phenomenon, the stream flow field and desert flow field are
introduced and mathematical model for numerical analysis are established by considering the sand
shape, size and mass in order to describe the fixed, semi-fixed and fully free sand desert
physiographical process. Then according to the real fixed, semi-fixed and free sand flow field by
coupling with stream flow field, several models are made and numerical simulations are conducted.
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.
In this study, to conduct numerical simulation of sand dune forming processes, the
mathematical model for sand dune dynamics are studied. Due to sand dune dynamics and the stream
field, which includes wind flow over a dune field, analyses process is complex the uniform sand field
and stream fields are consider for the numerical simulation process. Then the dune forming process
simulated by considering the dunes induced factor and interactions phenomenon.
In this paper, the iBone (Imitation Bone) model which is coupled with Turing
reaction-diffusion system and FEM, is used. The numerical simulation of bone forming process by
considering the osteoclasts and osteoblasts process are conducted. The results shown, that the bone
mass is increased with increase of the initial load value, then fibula and femur bones are obtained
respectively by keeping the required bone forming value. The different bone shapes are obtained by
changing the both bone keeping value and the compressing force value. When set larger bone keeping
value by keeping larger constant compressing force value, bone shape as a pipe with hole just like
femur, when set smaller bone keeping value by keeping the smaller constant compressing force value,
it is close to solid pillar as like fibula.
Wind caused the much sediment fluxes leading to both erosion and deposits in the sandy desertification area, and the much kind of beautiful sandy desert morphologies are formed. This is really crucial to the development of the dynamic behaviour of aeolian transport of sand particles. The sand desert morphologies are representing significant information archives for understanding the desertification problem. Dynamics and numerical modeling provides an essential tool for studying the aeolian transport of sand particle and morphology of sand desert such as ripple and dune. In this study, the mathematical models based on the dynamics are analyzed by considering the several keys as saltation, creep, suspension, avalanche and its threshold condition etc. for sand morphology forming processes. Then due to sand flow field real characteristics, the establishing process of stream flow field are analyzed, and the implication relationships as well as the coupling process between uniform stream flow field and the sand flow field are analyzed. Finally, the sand flow field models is discretized, and different kinds of sandy desert morphology are simulated by considering the sand particle size and mass in fixed, semi-fixed and free sand flow field area.
In this study, for the numerical simulation of the sand ripple’s forming process which
caused by the sand flow, the simulation models based on the fluid dynamics and the sand flow field by
the wind are analyzed. Due to sand field’s characteristics is very complex, the establishing process of
stream flow field constitutive equations analyzed at first, and then the implication relations and
independency between stream flow field and the sand flow field analyzed. Finally, the sand ripple
forming and moving process simulated in uniform and non-uniform stream flow field.
In this study, the directionally fixed air tunnel testing equipment are used for obtain nearly
close natural uniform wind and provide more stable wind speed for tunnel test. The changes of sand
ripple moving speed in different location are observed under given wind speed condition. The sand
ripple lines formation and moving process are tested on flat surface of sand, in Taklimakan desert.
The results shown that the sand ripple forming rapidly from non ripple surface to ripple surface and
moving along the wind direction. Though the sand ripples in the testing region have some difference
about its moving speed, the sand ripple moving speed appear linearity relationship between sand
moving displacement and the moving time. This phenomenon indicate that the sand ripple almost
occurs and moving at the same time in the uniform wind stream field.
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