Slip in flows of power-law liquids past smooth spherical particles

The effect of slip in flows of power-law liquids past smooth spherical particles is numerically studied by using Navier’s linear slip model. For computational simplicity, a sphere-in-sphere type computational domain has been chosen. Thus, the governing conservation equations of mass and momentum are considered in spherical coordinates. These are solved by using a finite difference method-based simplified marker and cell algorithm implemented on a staggered grid arrangement. The non-Newtonian terms of the momentum equation are discretized by a second-order central differencing scheme, whereas the convective terms are discretized by using QUICK scheme. The reliability and accuracy of the solver is established by comparing the present numerical results with the existing literature counterparts. Furthermore, extensive new results are obtained in the range of conditions for Reynolds number, Re: 0.1–200; power-law behavior index, n: 0.5–1.6; and a dimensionless slip parameter, λ: 0.01–100. Finally, effects of these dimensionless parameters on near surface flow kinematics are thoroughly delineated.     

Product types and supplier roles in product development: anexploratory analysis

Manufacturers today often strive toward early supplier involvement in product development. Yet the research literature offers limited guidance on this issue to manufacturing companies and suppliers, and often assumes a "one-size-fits-all" approach. In this paper, we empirically examine whether suppliers for different sourced products play distinctly different roles in product development, by analyzing survey data on a wide range of sourced automotive products. We use cluster analysis to identify four different groupings of sourced products, based on differences along three dimensions: the nature of the sourced products, their cost structures, and the nature of the original equipment manufacturer (OEM)-supplier interaction in product development. We further test the usefulness of our scheme via a set of validating variables that include both key decisions and output performance measures in the OEM-supplier interaction process. We identify critical systems as highly differentiating, high cost, highly complex systems, for which OEMs provide information to their suppliers largely through performance specifications, and involve suppliers early in product development. In contrast, hidden components are less differentiating low-cost simple components that are defined primarily via physical specifications, whose suppliers are involved later in product development. Invisible subassemblies are nondifferentiating, moderately costly, moderately complex systems whose suppliers are provided information via a mix of performance specifications and detailed physical dimensions. Finally, simple differentiators are highly differentiating, moderately costly, simple assemblies or components. We discuss the implications of our study for managing differential supplier roles in product development