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Three‐dimensional flows over backward facing s.tif are analysed by means of a finite element procedure, which shares many features with the SIMPLER method. In fact, given an initial or guessed velocity field, the pseudovelocities, i.e. the velocities that would prevail in the absence of the pressure field, are found first. Then, by enforcing continuity on the pseudovelocity field, the tentative pressure is estimated, and the momentum equations are solved in sequence for velocity components. Afterwards, continuity is enforced again to find corrections that are used to modify the velocity field and the estimated pressure field. Finally, whenever necessary, the energy equation is solved before moving to the next step.

The paper adopts a simplified two‐dimensional approach to deal with convective heat and mass transfer in laminar flows of humid air through wavy finned‐tube exchangers. The computational domain is spatially periodic, with fully developed conditions prevailing at a certain distance from the inlet section. Both the entrance and the fully developed flow region are investigated. In the fully developed region, periodicities in the flow, temperature and mass concentration fields are taken into account. The approach is completely general, even if the finite element method is used for the discretizations. In the application section, velocity, temperature, and mass concentration fields are computed first. Then apparent friction factors, Nusselt numbers, Colburn factors for heat and mass transfer, and goodness factors are evaluated both in the entrance and in the fully developed region.

Three‐dimensional laminar forced convective heat transfer in ribbed square channels is investigated. In these channels, transverse and angled ribs are placed on one or two of the walls to form a repetitive geometry. After a short distance from the entrance, also the flow and the dimensionless thermal fields repeat themselves from module to module allowing the assumption of periodic, or anti‐periodic, conditions at the inlet/outlet sections of the calculation cell. Prescribed temperature boundary conditions are assumed at all solid walls, including the ribs. Pressure drop and heat transfer characteristics are compared for rib angles ranging from 90° (transverse ribs) to 45°, and different values of the Reynolds number. The influence of rib geometries is investigated below and above the onset of the self‐sustained flow oscillations that precede the transition to turbulence. Numerical simulations are carried out employing an equal order finite‐element procedure based on a projection algorithm.

By neglecting the influence of tubes, this paper adopts a simplified two‐dimensional approach to deal with laminar convection of air through wavy finned‐tube exchangers. Pressure drop and heat transfer characteristics are investigated in the fully developed region of the flow channels between adjacent fins. The solutions are presented for several space ratios (height over length of a module) and two corrugation angles. They concern laminar flows both below and above the onset of the self‐sustained oscillations that precede the transition to turbulence. Fully developed velocity and thermal fields are computed by imposing anti‐periodic conditions at inlet/outlet sections of a single calculation cell. In the range of Reynolds numbers investigated, Nusselt numbers and friction factors first increase with space ratios (up to a value depending on the corrugation angle), then start decreasing with increasing space ratios.

Most compact heat exchangers and heat dissipating components rely on convection enhancement mechanisms that reduce the continuous growth of boundary layers. Usually surface irregularities, in the form of interruptions and/or vortex generators, are introduced in the flow passages. The resulting geometric configurations are periodic in space and, after a short distance from the entrance, induce velocity and thermal fields that repeat themselves from module to module. The numerical models presented here consider the space‐periodicity and allow flows that are stationary at sub‐critical values of the Reynolds number, but become time‐periodic, or quasi periodic, above the critical value of the Reynolds number. Space discretizations are achieved by an equal order finite element procedure based on a projection algorithm. Two‐dimensional schematizations are employed to analyze the effects of surface interruptions and transverse vortex generators, while three‐dimensional schematizations are employed for longitudinal vortex generators.

The purpose of this paper is to examine the modeling of simultaneous heat and mass transfer under dehumidifying conditions. Moist air cooling in tube‐fin exchangers is investigated using a finite element technique.

The model requires the solution of a conjugate problem, since interface temperatures must be calculated at the same time as temperature distributions in adjacent fluid and solid regions. The energy equation is solved in the whole domain, including the solid region, and the latent heat flux on the surfaces where condensation takes place is taken into account by means of an additional internal boundary condition.

Thermal performances for different Reynolds numbers of a typical two‐row tube‐fin exchanger are numerically analysed, for both in‐line and staggered arrangements of tubes. The results justify the great importance that the ratio between latent and overall rates of heat transfer has in the design of compact heat exchangers.

In this work, the capabilities of the proposed methodology to deal with industrial applications in the field of compact exchangers are outlined.

The paper presents an effective approach to the solution of conjugate conduction and convection problems with simultaneous heat and mass transfer. The formulation is completely general, even if the finite element method is used in the calculations.

Purpose: The insurance business is confronted with coordination difficulties that necessitate a high level of mobility, flexibility, and the capacity to analyse heterogeneous, location-dependent data from different sources and qualities. Recent innovations in emerging technologies have given the insurance industry new organisational options. When coupled with data analytics, crowdsourcing in the insurance industry facilitates solving complex issues with the wisdom of crowds. The notion of incorporating crowdsourcing and big data into the mainstream activities of insurance management is developed in this article, as are the ramifications and gains of collective intelligence achieved by Crowdsourcing and the added value of crowdsourcing insurance activities.

Design/methodology/approach: This chapter is a conceptual work that builds on relevant literature.

Findings: This chapter analyses what insurance industry managers should consider when coordinating crowdsourced activities and how they may benefit from collective intelligence combined with data analytics in terms of efficient and real-time response management for the insurance industry. Furthermore, it is demonstrated how they may use crowdsourcing to exploit information and benefit from invoking additional resources and eliminating the institutional voids present in the industry.

Practical implications: Exemplary applications that take advantage of crowdsourcing and data analytics would help the insurance sector respond flexibly, efficiently, and effectively in real time.

Originality/value: This chapter offers new collaborative ways to enhance the decision-making of insurance industry managers. The relevance of overcoming institutional voids is expanded, and repercussions from the given framework are suggested using data analytics.

The purpose of this paper is twofold: to describe a relevant improvement to an in-house FEM procedure for the heat transfer analysis of cross-flow micro heat exchangers and to study the influence of microchannel cross-sectional geometry and solid wall thermal conductivity on the thermal performance of these microdevices.

The velocity field in each microchannel is calculated separately. Then the energy equation is solved in the whole computational domain. Domain decomposition and grids that do not match at the common interface are employed to make meshing more effective. Some flow maldistribution effects are taken into account.

The results show that larger thermal conductivities of the solid walls and rectangular cross-sectional geometries with higher aspect ratios allow the maximization of the total heat flow rate in the device. However, on the basis of the heat transfer per unit pumping power, the square cross-section could be the best option.

The value of the average viscosity is assumed to be different in different microchannels, but constant within each of the microchannels.

The procedure can represent a valuable tool for the design of cross-flow micro heat exchangers.

In spite of requiring limited computational resources, the improved procedure can take into account flow maldistribution effects stemming from non-uniform microchannel temperatures.

The purpose of this paper is to develop a simplified but accurate finite element procedure for the analysis of the conjugate conduction-convection heat transfer in cross-flow micro heat exchangers.

The velocity fields in single microchannels are calculated by solving the parabolised form of the momentum equations and later mapped onto the three-dimensional grid, corresponding to an appropriate portion of the micro heat exchanger, which is used for the solution of the energy equation in its elliptic form. To allow the use of finite elements elongated in the flow direction, layers of perpendicular microchannels can be meshed independently with grids that do not match at the common interface (domain decomposition).

An original and easy-to-implement method has been developed to deal with non-matching grids. Computed results show that increasing the number of microchannels per layer yields relative pressure drop increments that are larger than those displayed by the relative heat flow rates.

The simplified procedure requires the assumption of constant thermophysical properties. The adopted domain decomposition technique yields non-symmetric system matrices.

The procedure can be very useful in the design of cross-flow micro heat exchangers.

The finite element procedure described in the paper requires only limited computational resources for the analysis of the conjugate conduction-convection heat transfer in cross-flow micro heat exchangers with a large number of microchannels per layer.

The purpose of this paper is to propose an in-depth analysis of online communities of practice that support the innovative development of web applications. The analysis is aimed at understanding the preeminent characteristics of communities of practice that can favour the process of innovation (conceptualisation and realization of a web application) and if these characteristics differ in the diverse phases of a software development project (requirement specification, design, implementation and verification).

The authors adopted a multiple case study research design, selected 29 communities of practice related to the development of web applications and classified them recognizing the different practices that refer to the different phases of the innovation process of web-applications software development. Finally, the authors focussed on seven communities comparing five important dimensions for each one.

The results of the empirical analysis show that the best practices are different, considering the different phases of the project, and that these practices can be strategies directed at members to attract them and also, strategies directed at the community to permit collaboration.

The paper proposes an important and new insight into the management of virtual communities of practice (VCoP). The authors supposed that the ways to manage a VCoP could depend on project phases. In particular, the management practices of community should differ according to the different project phases, i.e. requirements specification, design, implementation and verification of the software. Literature in this sense presented only research focussed on the different effects of virtualness on teams depending on the length of team duration and on communication efforts.