Experimental Analysis of Velocity Distribution in a Coarse-Grained Debris Flow: A Modified Bagnold’s Equation
| Autor: | Antonio Fichera, Donatella Termini |
|---|---|
| Přispěvatelé: | Termini, D., Fichera, A. |
| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
lcsh:Hydraulic engineering
010504 meteorology & atmospheric sciences Mean squared error Geography Planning and Development Aquatic Science 01 natural sciences Biochemistry 010305 fluids & plasmas Debris flow flow velocity debris flows lcsh:Water supply for domestic and industrial purposes lcsh:TC1-978 0103 physical sciences sediment concentration 0105 earth and related environmental sciences Water Science and Technology lcsh:TD201-500 Function (mathematics) Mechanics Debris Sediment concentration Flume Distribution (mathematics) Flow velocity prevision Geology |
| Zdroj: | Water, Vol 12, Iss 1415, p 1415 (2020) Water Volume 12 Issue 5 |
| Popis: | Today, Bagnold&rsquo s theory is still applied to gravity-driven flows under the assumption of uniform sediment concentration. This study presents findings of flume experiments conducted to investigate the velocity and concentration distributions within the debris body by using high-resolution images. The analysis has shown that the concentration and mobility of grains vary along the depth. A linear law to interpret the grains concentration distribution, starting from the knowledge of the packing concentration and of the surface concentration, Cs, has been identified. By considering such a law, modified expressions of the Bagnold&rsquo s number and the velocity in stony-type debris flows are also presented. By using these expressions, three regimes of motion have been identified along the depth, and the velocity profile within the debris body is determined as a function of the parameter Cs. It has been verified that the velocity profiles estimated by using the modified equation compare well (mean square error less than 0.1) with the literature&rsquo s measured profiles when Cs is correctly measured or estimated. Results of cutting tests, conducted for a sample of the used material, have also allowed us to verify that Cs could be determined as a function of the static friction angle of the material. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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