The Mechanics of Mud Flow

Arai, Muneyuki; Takahashi, Tamotsu

doi:10.2208/jscej.1986.375_69

Cited by 5 publications

(4 citation statements)

References 10 publications

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“…The experimental friction coefficient f was calculated using compiled experimental data as where g is the acceleration due to gravity, h is the flow depth, and u m is the mean velocity. The relationship between f and h/d was determined by Arai and Takahashi [1986], Ashida et al [1988], and Hirano et al [1992]. The experimental f in Eq.…”

Section: Discussionmentioning

confidence: 99%

“…However, the critical Reynolds number to indicate either the laminar or turbulent flow phases was not determined, since no experimental investigations were conducted. In the area of experimental investigations, Arai and Takahashi [1986] and Hirano et al [1992] focused on a friction coefficient theoretically derived for a boulder debris flow and a turbulent flow. Based on a comparison between their theoretical curves and experimental data, Arai and Takahashi [1986] and Hirano et al [1992] maintained that phase transition in debris flows occurs at an h/d value of approximately 30-100.…”

Section: Introductionmentioning

confidence: 99%

“…In the area of experimental investigations, Arai and Takahashi [1986] and Hirano et al [1992] focused on a friction coefficient theoretically derived for a boulder debris flow and a turbulent flow. Based on a comparison between their theoretical curves and experimental data, Arai and Takahashi [1986] and Hirano et al [1992] maintained that phase transition in debris flows occurs at an h/d value of approximately 30-100. However, since most of their experimental data were distributed around the crossing point of the theoretical lines, the results were not absolutely clear.…”

Section: Introductionmentioning

confidence: 99%

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Phase classification of laboratory debris flows over a rigid bed based on the relative flow depth and friction coefficients

Hotta

Miyamoto

2008

IJECE

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The friction coefficients of debris flows over a rigid bed from several previous experiments were compiled in a preliminary investigation on the classification of phase transitions in debris flows. The collected friction coefficients were compared to the theoretical values of the friction coefficients in the relationship with the relative flow depth on the basis of sediment particle size (h/d) under various conditions. The friction coefficients of debris flows with h/d values less than 20 agreed closely with the theoretical value for boulder debris flows derived from the constitutive equations, while the friction coefficients with h/d values in the range 1000-10,000 agreed roughly with the theoretical value for turbulent water flows. The friction coefficients with h/d values of 30-300 exceeded the theoretical value for both debris and turbulent water flows. These intermediate debris flows were observed in experiments involving turbulent mud flows. However, a review of these experiments revealed that they may have included debris flows in which the turbulent structure was not well developed, and could be considered as debris flows in transition from laminar to turbulent flows. In some of the transitional debris flows, an interface dividing the flow structure into an upper turbulent-flow layer and a lower debris-flow layer was observed as reported for sediment-laden flows. The friction coefficient for transitional debris flows was modeled considering the shift of this interface. The model was able to explain the value for transitional debris flows, inferring that phase transition in debris flows from laminar to turbulent flows is induced by the shift of the interface.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phase classification of laboratory debris flows over a rigid bed based on the relative flow depth and friction coefficients

Hotta

Miyamoto

2008

IJECE

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“…Takahashi [1982] described immature debris flow, which is composed of coarse particles with no particles suspended in the upper layer, and Arai and Takahashi [1986] reported on turbulent muddy debris flow, which is composed of fine particles and has a thin lower layer. Mizuyama [1980] empirically obtained the equilibrium solids concentration of immature debris flow C s∞ .…”

Section: Mechanics Of Flowmentioning

confidence: 99%