Vsm 90[gnSs

Here n represents the kinematic viscosity of the carrier fluid (i.e. m/p), and the coefficient of 9.0 applies in any consistent system of units. This equation gives the minimum value of deposition velocity for small particles, assuming turbulent flow.

For cases where the interfacial friction sets up a sheared layer several grain diameters in thickness, a new analysis has been developed (Wilson, 1988; Wilson & Nnadi, 1990). For large pipes, and particles near the Murphian size, this new analysis shows that the particle size no longer influences Vsm directly. In such cases the value of Vsm is less than that predicted by Figure 6, a point which is in accord with experimental evidence. It is then necessary to obtain the value of Vsm from the new analysis of Interfacial friction, for comparison with the value from the nomographic chart.

When the parameters in the new analysis are given values typical for sands, it is found that the dimensionless maximum deposition velocity (i.e. the Durand deposition variable) depends only on the fluid friction factor for the portion of the pipe wall above the deposit. A power-law approximation gives an appropriate fit function for this effect, i.e.

Survival Treasure

Survival Treasure

This is a collection of 3 guides all about survival. Within this collection you find the following titles: Outdoor Survival Skills, Survival Basics and The Wilderness Survival Guide.

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