| Experimental investigation of density current patterns using dynamic fractal analysis |
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| 作者姓名： | Mohammad Hosseini Mohammad Hadi Fattahi Saeid Eslamian |
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| 作者单位： | Department of Civil Engineering;Department of Civil Engineering;Department of Water Engineering |
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| 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 the ambient 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 a good correlation with a coefficient of determination of 0.76.
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| 关 键 词： | Density current Fractal geometry Richardson number Multi-fractal analysis Fluid interface |
| 收稿时间： | 4 January 2020 |
Experimental investigation of density current patterns using dynamic fractal analysis |
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| Mohammad Hosseini,Mohammad Hadi Fattahi,Saeid Eslamian.Experimental investigation of density current patterns using dynamic fractal analysis[J].International Journal of Sediment Research,2021,36(2):165-176. |
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| Authors: | Mohammad Hosseini Mohammad Hadi Fattahi Saeid Eslamian |
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| Institution: | 1. Department of Civil Engineering, Najafabad Branch, Islamic Azad University, Najafabad, Iran;2. Department of Civil Engineering, Marvdasht Branch, Islamic Azad University, Marvdasht, Iran;3. Department of Water Engineering, Isfahan University of Technology, Isfahan, Iran |
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| Abstract: | 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 the ambient 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 a good correlation with a coefficient of determination of 0.76. |
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| Keywords: | Density current Fractal geometry Richardson number Multi-fractal analysis Fluid interface |
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