A Numerical Investigation of Transformation Rates from Debris Flows to Turbidity Currents under Shearing Mechanisms
The evolution of a submarine landslide is a very complicated process due to slurry–water interactions. Most previous studies have focused on debris flows or turbidity currents independently. Little research has been conducted on the processes of transformation from debris flows into turbidity curren...
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MDPI AG
2023-03-01
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| Online Access: | https://www.mdpi.com/2076-3417/13/7/4105 |
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| author | Yizhe Li Youkou Dong Gang Chen |
| author_facet | Yizhe Li Youkou Dong Gang Chen |
| author_sort | Yizhe Li |
| collection | DOAJ |
| description | The evolution of a submarine landslide is a very complicated process due to slurry–water interactions. Most previous studies have focused on debris flows or turbidity currents independently. Little research has been conducted on the processes of transformation from debris flows into turbidity currents. Moreover, the underlying mechanical mechanisms of these transformation processes are not well understood. In this study, we aimed to better understand these mechanisms by simulating submarine landslide transportation processes using computational fluid dynamics. In the numerical models, the two-phase mixture module was adopted to mimic the interactions of the slurry with the ambient water, which we validated through a dam-break case. Here, the rheological behaviors of the slurries are described using the Herschel–Bulkley model. A formula for transformation rates is best fitted through a case series of debris flows. In particular, the activation stress is expressed by the dynamic pressure at the moment when the slurry starts to mobilize, which is fitted as a coefficient 6.55 × 10<sup>−5</sup> times the shear strength. Then, two coefficients in the formula of the transformation rate are fitted as 1.61 and 0.26, respectively, based on the cases of debris flows, considering their different initial thicknesses, levels of slurry consistency and slope angles. Finally, in a real-scale debris flow case study, we demonstrate that the slurry is fully transformed before it is deposited. The expected outcome, the mechanical theory, the activation stress and the transformation rate would be applied to assess the influence area of the realistic turbidity currents and their harm to the subsea environment. |
| first_indexed | 2024-03-11T05:43:28Z |
| format | Article |
| id | doaj.art-157d123ad2d646a5ae325d98066bd4e1 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-11T05:43:28Z |
| publishDate | 2023-03-01 |
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| spelling | doaj.art-157d123ad2d646a5ae325d98066bd4e12023-11-17T16:15:36ZengMDPI AGApplied Sciences2076-34172023-03-01137410510.3390/app13074105A Numerical Investigation of Transformation Rates from Debris Flows to Turbidity Currents under Shearing MechanismsYizhe Li0Youkou Dong1Gang Chen2College of Marine Science and Technology, China University of Geosciences, 388 Lumo Road, Wuhan 430074, ChinaCollege of Marine Science and Technology, China University of Geosciences, 388 Lumo Road, Wuhan 430074, ChinaCollege of Marine Science and Technology, China University of Geosciences, 388 Lumo Road, Wuhan 430074, ChinaThe evolution of a submarine landslide is a very complicated process due to slurry–water interactions. Most previous studies have focused on debris flows or turbidity currents independently. Little research has been conducted on the processes of transformation from debris flows into turbidity currents. Moreover, the underlying mechanical mechanisms of these transformation processes are not well understood. In this study, we aimed to better understand these mechanisms by simulating submarine landslide transportation processes using computational fluid dynamics. In the numerical models, the two-phase mixture module was adopted to mimic the interactions of the slurry with the ambient water, which we validated through a dam-break case. Here, the rheological behaviors of the slurries are described using the Herschel–Bulkley model. A formula for transformation rates is best fitted through a case series of debris flows. In particular, the activation stress is expressed by the dynamic pressure at the moment when the slurry starts to mobilize, which is fitted as a coefficient 6.55 × 10<sup>−5</sup> times the shear strength. Then, two coefficients in the formula of the transformation rate are fitted as 1.61 and 0.26, respectively, based on the cases of debris flows, considering their different initial thicknesses, levels of slurry consistency and slope angles. Finally, in a real-scale debris flow case study, we demonstrate that the slurry is fully transformed before it is deposited. The expected outcome, the mechanical theory, the activation stress and the transformation rate would be applied to assess the influence area of the realistic turbidity currents and their harm to the subsea environment.https://www.mdpi.com/2076-3417/13/7/4105submarine landslidedebris flowturbidity currentsolid concentrationshearing mechanismcomputational fluid dynamics |
| spellingShingle | Yizhe Li Youkou Dong Gang Chen A Numerical Investigation of Transformation Rates from Debris Flows to Turbidity Currents under Shearing Mechanisms Applied Sciences submarine landslide debris flow turbidity current solid concentration shearing mechanism computational fluid dynamics |
| title | A Numerical Investigation of Transformation Rates from Debris Flows to Turbidity Currents under Shearing Mechanisms |
| title_full | A Numerical Investigation of Transformation Rates from Debris Flows to Turbidity Currents under Shearing Mechanisms |
| title_fullStr | A Numerical Investigation of Transformation Rates from Debris Flows to Turbidity Currents under Shearing Mechanisms |
| title_full_unstemmed | A Numerical Investigation of Transformation Rates from Debris Flows to Turbidity Currents under Shearing Mechanisms |
| title_short | A Numerical Investigation of Transformation Rates from Debris Flows to Turbidity Currents under Shearing Mechanisms |
| title_sort | numerical investigation of transformation rates from debris flows to turbidity currents under shearing mechanisms |
| topic | submarine landslide debris flow turbidity current solid concentration shearing mechanism computational fluid dynamics |
| url | https://www.mdpi.com/2076-3417/13/7/4105 |
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