SIMULATION OF EOLIAN SALTATION
SIMULATION OF EOLIAN SALTATION
复制标题
DOI：
10.1126/science.241.4867.820
复制
发表时间：
1988-08-12
期刊：
影响因子：
56.9
通讯作者：
HAFF, PK
中科院分区：
文献类型：
--
作者：
ANDERSON, RS;HAFF, PK
在用风输送沙子大小的颗粒物质以及在地球和火星上将尘埃从床上喷射出来时，跳跃都是重要的。跳跃的种群及其所有特征轮廓的演变是通过纯空气动力卷吸到稳定状态来计算的。单颗粒撞击颗粒床的数值模拟结果被浓缩为颗粒从床上反弹或喷射(飞溅)的数量和速度的解析表达式。模型结合了(I)这个数值表示，(Ii)空气动力卷吸速率的表达式，和(Iii)跳跃颗粒对风速剖面的修正。计算的稳态质量通量在风洞实验测得的质量通量范围内；质量通量与剪切速度呈非线性关系。系统中的空气动力学夹带颗粒主要是播种剂；在稳定状态下，空气动力夹带很少。整个系统达到稳定状态的时间大约是1秒，或者说几个长轨迹跳跃时间。
Saltation is important in the transport of sand-sized granular material by wind and in the ejection of dust from the bed both on Earth and on Mars. The evolution of the saltating population and all its characteristic profiles is calculated from inception by pure aerodynamic entrainment through to steady state. Results of numerical simulations of single-grain impacts into granular beds are condensed into analytic expressions for the number and speeds of grains rebounding or ejected (splashed) from the bed. A model is combined with (i) this numerical representation, (ii) an expression for the aerodynamic entrainment rate, and (iii) the modification of the wind velocity profile by saltating grains. Calculated steady state mass fluxes are within the range of mass fluxes measured in wind tunnel experiments; mass flux is nonlinearly dependent on the shear velocity. Aerodynamically entrained grains in the system are primarily seeding agents; at steady state, aerodynamic entrainment is rare. The time for the entire system to reach steady state is roughly 1 second, or several long-trajectory hop times.