Experimental investigation of density current patterns using dynamic fractal analysis

• 作者: Mohammad Hadi Fattahi Mohammad Hosseini Saeid Eslamian
• 来源期刊: 国际泥沙研究（英文版）
• 年，卷（期）: 2021,（2）
• 页码范围: 165-176
• 页数: 12页
• 语种: 英文

摘要

Density currents are caused by a difference in density,though low,of an entering fluid with the ambient fluid.This type of current is two-phased and found on riverbeds or in reservoirs behind dams,and is nonlinear in nature,complex,and sensitive to initial conditions.Fractal geometry is used as a powerful tool for studying complex natural phenomena.Using experimental studies and changes in inlet current conditions,the fractal and multi-fractal analyses of the interface between the density current and theambient fluid were done.In addition,a search was made to find a possible connection between the nonlinear patterns.According to the results,with an increase in the inlet discharge and inlet density of the current the fractal dimension decreased.Further,the smaller the range of the singularity spectrum diagram was,i.e.,the more it was less than 0.34,the lower the system's tendency was to be multi-fractal,and the system sensitive to large local changes.In the interface between the density current and the ambient fluid,using the fractal dimension-based Richardson number could improve experimental data by 12.4％.Moreover,with an increase in the Richardson number,the Reynolds number of the current decreased.Further,upon considering the fractal dimension,the Reynolds number improved by 23％ and agood correlation with a coefficient of determination of 0.76.