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PREDICTION OF BOTHFLOOD AND ACCUMULATION DISTRIBUTIONS OF VOLCANIC ASH IN REVERE BY MEANS OF LAGRANGE METHODS

拉格朗日法对Revere火山灰洪水和堆积分布的预测

基本信息

批准号：
07650215
负责人：
TORII Shuichi
金额：
$ 1.34万
依托单位：
KAGOSHIMA UNIVERSTIY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07650215/
关键词：
Volcanic Ash Shirasu Solid-Liquid Phase Flow Numerical Analysis Revere lmprovement Turbulence Model シラスム固液二相流

项目摘要

An experimental and numerical study has been performed to predict both the flood and the accumulation distribution of volcanic ash in reveres. The experimental apparatus used here was consisted of a slender rectangular open channel (simulating a revere with a 2-D flow field in the streamwise and normal directions) with a side wall which was made of acrylic windows for illumination and observation. Water mixed with neutrally buoyant solid particles (polypropylene spheres 50 mm in diameter) was used to simulate the flow phenomena in revere which flowed steadily at a constant volumetric rate. The mixture was supplied from the upper tank. The corresponding numerical analysis was carried out using the k-epsilon turbulence model. A set of governing equations was solved using the control volume finite-difference procedure developed by Patankar. The discretized equations were solved from the inlet along the flow direction by means of a marching procedure, because of the parabolic equations. It was found from the study that (i) the uniform particle distribution in the revere is observed through the direct photographic method, (ii) the predicted radial distributions of the time-averaged streamwise velocity show the well-known characteristics near the wall region and turbulent core regions, and (iii) the prediction reproduces the turbulent characteristics in which the turbulent kinetic energy is substantially increased in the vicinity of the wall and is gradually decreased along the free surface. Through the above comparisons, the validity of the computer code and the accuracy for the turbulence models of heat and momentum employed here are confirmed.

通过实验和数值模拟研究，预测了洪水和火山灰在河流中的堆积分布。实验装置是一个细长的矩形明渠（模拟在流向和法向的二维流场），其侧壁由丙烯酸玻璃窗制成，用于照明和观察。水与中性浮力固体颗粒（直径50 mm的聚丙烯球）混合，用于模拟在revere中以恒定体积速率稳定流动的流动现象。混合物从上部罐供应。采用k-ε湍流模型进行了相应的数值分析。一组控制方程求解使用控制体积有限差分程序开发的帕坦卡。由于离散后的方程为抛物型方程，因此从进口沿着流动方向采用步进法求解。研究发现：（1）直接照相法观察到了均匀的颗粒分布;（2）预测的时均流向速度径向分布在近壁区和湍流核心区具有众所周知的特征，以及（iii）预测再现了湍流特性，其中湍流动能在壁附近显著增加，并且逐渐增加。沿自由表面沿着减小。通过以上比较，证实了程序的正确性和所采用的热、动量湍流模型的准确性。