SLD破碎效应对冰型的影响研究

SLD(Supercooled large droplets,超大直径过冷水滴)为超过100微米的过冷水滴,这种结冰环境其在目前的适航规范中没有相应规定。和小直径水滴相比(小于50微米),SLD结冰是多个动力学(破碎,撞击飞溅,流动)和热力学过程的组合,各个环节对冰型也有不同的作用。本文参照TAB破碎模型建立了SLD破碎模型,并对破碎过程的主要环节的影响进行了分析,分析了水滴在翼型附近的运动情况,并结合飞溅模型对SLD环境中的冰型生长进行了数值模拟。模拟结果和冰风洞实验结果符合的较好。

Three-dimensional numerical simulation of glacial trough forming process

The glacial trough is a common glacier erosion landscape, which plays an important role in the study of glacier erosion processes. In a sharp contrast with the developing river, which is generally meandering, the developing glacial trough is usually wide and straight. Is the straightness of the glacial trough just the special phenomenon of some areas or a universal feature? What controls the straightness of the glacial trough? Until now, these issues have not been studied yet. In this paper, we conduct systematic numerical models of the glacier erosion and simulate the erosion evolution process of the glacial trough. Numerical simulations show that:(1) while the meandering glacier is eroding deeper to form the U-shaped cross section, the glacier is eroding laterally. The erosion rate of the ice-facing slope is bigger than that of the back-slope.(2) The smaller(bigger) the slope is, the smaller(bigger) the glacier erosion intensity is.(3) The smaller(bigger) the ice discharge is, the smaller(bigger) the glacier erosion intensity is. In the glacier erosion process, the erosion rate of the ice-facing slope is always greater than that of the back-slope. Therefore, the glacial trough always develops into more straight form. This paper comes to the conclusion that the shape evolution of the glacial trough is controlled mainly by the erosion mechanism of the glacier. Thereby, the glacial trough prefers straight geometry.