Dynamics and Numerical Modeling of Sandy Desert Morphology Caused by Aeolian Transport of Sand Particles

2011 ◽  
Vol 462-463 ◽  
pp. 1038-1043 ◽  
Author(s):  
Xamxinur Abdikerem ◽  
Mamtimin Gheni ◽  
Abdurahman Ablimit ◽  
A Fang Jin
Keyword(s):  
Numerical Modeling ◽  
Flow Field ◽  
Stream Flow ◽  
Sand Particle ◽  
Threshold Condition ◽  
Sandy Desert ◽  
Aeolian Transport ◽  
Significant Information ◽  
Sand Flow ◽  
Sand Particles

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.

Numerical Modeling for Sand Desert Morphology and Forming Process in Fixed, Semi-Fixed and Free Desert Field

2008 ◽  
Vol 33-37 ◽  
pp. 1055-1062 ◽  
Author(s):  
Xamxinur Abdikerem ◽  
Zhong Hua Xu ◽  
Mamtimin Gheni
Keyword(s):  
Numerical Simulation ◽  
Mathematical Model ◽  
Numerical Modeling ◽  
Numerical Model ◽  
Flow Field ◽  
Stream Flow ◽  
Forming Process ◽  
Flow Process ◽  
Sand Movement ◽  
Sand Flow

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.

Numerical Study on Aeolian Sand Ripples Forming and Moving Process in Desert Highway

2011 ◽  
Vol 462-463 ◽  
pp. 1032-1037 ◽  
Author(s):  
Abdurahman Ablimit ◽  
Mamtimin Gheni ◽  
Zhong Hua Xu ◽  
Mamatjan Tursun ◽  
Xamxinur Abdikerem
Keyword(s):  
Flow Field ◽  
Numerical Study ◽  
Numerical Models ◽  
Flow Direction ◽  
Sand Particle ◽  
Forming Process ◽  
Sand Surface ◽  
Airflow Field ◽  
Sand Flow ◽  
Desert Highway

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.

scholarly journals Velocity difference changes between fluid and sand particles in boundary-layer and very near wake area

2021 ◽  
Vol 25 (6 Part A) ◽  
pp. 4217-4224
Author(s):  
Sha Sha ◽  
Xiantang Zhang ◽  
Zhiang Wang ◽  
Han Liu ◽  
Huiyao Zhang
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Cylindrical Surface ◽  
Dynamic Pressure ◽  
Fluid Velocity ◽  
Near Wake ◽  
Two Phase ◽  
Velocity Change ◽  
Sand Flow ◽  
Sand Particles

Fluent simulates the water-sand flow around a cylinder. Monitoring lines are set up at different positions in the cylindrical surface and the very near wake area behind the cylinder, in order to explore the speed difference of fluid and sand in the water-sand two-phase flow in the boundary-layer and the very near wake area. The results show that the sand particles stay for the longest time on the back of the cylindrical surface and in the very near wake area, and a small part of the sand particles are sticky on the back of the cylindrical pier. When the height of the cylinder is z/D ? (1.57, 3.14), the turbulent flow on the cylindrical surface is fully developed. The dynamic pressure of the flow field in the very near wake area be-hind the cylinder fluctuates greatly, and the water-sand flow is extremely unstable. At the monitoring position of the cylinder, there is a sudden decrease in the velocity of the fluid, while the velocity of the sand particles changes little and remains finally at about -0.02 m/s. The water-sand flow field near the wall changes drastically, but the velocity change of sand particles has obvious hysteresis compared with fluid. When leaving the near-wall position but still in the cylindrical wake area (x/D ? 3), the changes in the water-sand flow field are more intense and the velocity of the sand particles is still slightly larger than the fluid velocity.

Numerical Simulation of Sand Ripple Formation with Periodically Uniform and Non-Uniform Stream Field

2008 ◽  
Vol 33-37 ◽  
pp. 1063-1068 ◽  
Author(s):  
Abudoukelimu Abudoureheman ◽  
Xamxinur Abdikerem ◽  
Mamtimin Gheni
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Stream Flow ◽  
Simulation Models ◽  
Forming Process ◽  
Sand Ripple ◽  
Ripple Formation ◽  
Sand Flow ◽  
Moving Process ◽  
Uniform Stream

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.

scholarly journals Research of the resistance process of casing column filters at their contact with rock

2021 ◽  
pp. 1-12
Author(s):  
G. G. Gilaev ◽  
◽  
M. Ya. Khabibullin ◽  
R. N. Bakhtizin ◽  
◽  
...  
Keyword(s):  
Field Data ◽  
Filter Design ◽  
Experimental Methods ◽  
Coarse Fraction ◽  
Sand Particle ◽  
Main Task ◽  
Pressure Losses ◽  
Open Hole ◽  
Sand Flow ◽  
Sand Particles

The analysis of theoretical solutions and experimental data given in numerous literatures to justify the choice of the ratio of the size of gravel in relation to the size of formation sand showed that with the development of experimental methods and the accumulation of laboratory and field data, this ratio tends to decrease. When installing filters in an open hole, pressure losses at the interface between gravel and the formation play a significant role, and it should be noted that the greatest productivity and efficiency of the filter in an open hole is achieved when there is a packing around it, which can be created by crushing the sandy massif of the formation by cyclical changes debit. When choosing a filter design, along with the ability to provide them with a reliable hydraulic connection in the reservoir-filter system, the main task is also solved - to prevent sand flow into the well. The study of the conditions for the removal of sand particles through the flow sections in perforated, mesh and slotted filters during their operation both in homogeneous and in sands of different size, made it possible to recommend empirical dependences for determining the size of the holes. Keywords: porous medium; coarse fraction; sand; particle; well.

Numerical modeling of NITM-2 flow field

1992 ◽  
Author(s):  
ALAN CHOW ◽  
JIADA MO
Keyword(s):  
Numerical Modeling ◽  
Flow Field

CFD Leakage Predictions of Unworn and Worn Labyrinth Seals With and Without Tooth Axial Offset

2017 ◽  
Author(s):  
Hasham H. Chougule ◽  
Alexander Mirzamoghadam
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Modeling ◽  
Steady State ◽  
Flow Field ◽  
Labyrinth Seals ◽  
Small Clearance ◽  
Total Leakage ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Deflection

The objective of this study is to develop a Computational Fluid Dynamics (CFD) based methodology for analyzing and predicting leakage of worn or rub-intended labyrinth seals during operation. The simulations include intended tooth axial offset and numerical modeling of the flow field. The purpose is to predict total leakage through the seal when an axial tooth offset is provided after the intended/unintended rub. Results indicate that as expected, the leakage for the in-line worn land case (i.e. tooth under rub) is higher compared to unworn. Furthermore, the intended rotor/teeth forward axial offset/shift with respect to the rubbed land reduces the seal leakage. The overall leakage of a rubbed seal with axial tooth offset is observed to be considerably reduced, and it can become even less than a small clearance seal designed not to rub. The reduced leakage during steady state is due to a targeted smaller running gap because of tooth offset under the intended/worn land groove shape, higher blockages, higher turbulence and flow deflection as compared to worn seal model without axial tooth offset.

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