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The purpose of this study is to investigate the accuracy and applicability of the Flowfield Dependent Variation (FDV) method for large-eddy simulations (LES) of decaying isotropic turbulence.

In an earlier paper, the FDV method was successfully demonstrated for simulations of laminar flows with speeds varying from low subsonic to high supersonic Mach numbers. In the current study, the FDV method, implemented in a finite element framework, is used to perform LESs of decaying isotropic turbulence. The FDV method is fundamentally derived from the Lax–Wendroff Scheme (LWS) by replacing the explicit time derivatives in LWS with a weighted combination of explicit and implicit time derivatives. The increased implicitness and the inherent numerical dissipation of FDV contribute to the scheme’s numerical stability and monotonicity. Understanding the role of numerical dissipation that is inherent to the FDV method is essential for the maturation of FDV into a robust scheme for LES of turbulent flows. Accordingly, three types of LES of decaying isotropic turbulence were performed. The first two types of LES utilized explicit subgrid scale (SGS) models, namely, the constant-coefficient Smagorinsky and dynamic Smagorinsky models. In the third, no explicit SGS model was employed; instead, the numerical dissipation inherent to FDV was used to emulate the role played by explicit SGS models. Such an approach is commonly known as Implicit LES (ILES). A new formulation was also developed for quantifying the FDV numerical viscosity that principally arises from the convective terms of the filtered Navier–Stokes equations.

The temporal variation of the turbulent kinetic energy and enstrophy and the energy spectra are presented and analyzed. At all grid resolutions, the temporal profiles of kinetic energy showed good agreement with t^(−1.43) theoretical scaling in the fully developed turbulent flow regime, where t represents time. The energy spectra also showed reasonable agreement with the Kolmogorov’s k^(−5/3) power law in the inertial subrange, with the spectra moving closer to the Kolmogorov scaling at higher-grid resolutions. The intrinsic numerical viscosity and the dissipation rate of the FDV scheme are quantified, both in physical and spectral spaces, and compared with those of the two SGS LES runs. Furthermore, at a finite number of flow realizations, the numerical viscosities of FDV and of the Streamline Upwind/Petrov–Galerkin (SUPG) finite element method are compared. In the initial stages of turbulence development, all three LES cases have similar viscosities. But, once the turbulence is fully developed, implicit LES is less dissipative compared to the two SGS LES runs. It was also observed that the SUPG method is significantly more dissipative than the three LES approaches.

Just as any computational method, the limitations are based on the available computational resources.

Solving problems involving turbulent flows is by far the biggest challenge facing engineers and scientists in the twenty-first century, this is the road that the authors have embarked upon in this paper and the road ahead of is very long.

Understanding turbulence is a very lofty goal and a challenging one as well; however, if the authors succeed, the rewards are limitless.

The derivation of an explicit expression for the numerical viscosity tensor of FDV is an important contribution of this study, and is a crucial step forward in elucidating the fundamental properties of the FDV method. The comparison of viscosities for the three LES cases and the SUPG method has important implications for the application of ILES approach for turbulent flow simulations.

The purpose of this paper is to investigate the computational features of the Flowfield Dependent Variation (FDV) method, a numerical scheme built to simulate flows characterized by multiple speeds, multiple physical phenomena, and by large variations in flow variables.

Fundamentally, the FDV method may be regarded as a variant of the Lax-Wendroff Scheme (LWS) that is obtained by replacing the explicit time derivatives in LWS by a weighted combination of explicit and implicit time derivatives. The weighting factors – referred to as FDV parameters – may be broadly classified as convective and diffusive parameters which, for example, are determined using flow quantities such as the Mach number and Reynolds number, respectively. Hence, the reference to these parameters and the method as “flow field dependent.” A von Neumann Fourier analysis demonstrates that the increased implicitness makes FDV both more stable and less dispersive compared to LWS, a feature crucial to capturing shocks and other phenomena characterized by high gradients in variables. In the current study, the FDV scheme is implemented in a Taylor-Galerkin-based finite element method framework that supports arbitrarily high order, unstructured isoparametric elements in one-, two- and three-dimensional geometries.

At first, the spatial accuracy of the implemented FDV scheme is established using the Method of Manufactured Solutions, wherein the results show that the order of accuracy of the scheme is nearly equal to the order of the shape function polynomial plus one. The dispersion and dissipation errors of FDV, when applied to the compressible Navier-Stokes and energy equations, are investigated using a 2-D, small-amplitude acoustic pulse propagating in a quiescent medium. It is shown that FDV with third-order shape functions accurately captures both the amplitude and phase of the acoustic pulse. The method is then applied to cases ranging from low-Mach number subsonic flows (Mach number M=0.05) to high-Mach number supersonic flows (M=4) with shock-boundary layer interactions. For all cases, fair to good agreement is observed between the current results and those in the literature.

The spatial order of accuracy of the FDV method, its stability and dispersive properties, as well as its applicability to low- and high-Mach number flows are established.

This study measures the effect of each of the five senses on arousal, satisfaction and intention to revisit a live racing event. Spectators' arousal was significantly influenced by sights, sounds and smells. Spectators' sense of smell, taste, and touch directly impacted satisfaction. Interestingly, olfactory stimuli had an effect on both arousal and satisfaction. Spectators' arousal had a significant indirect effect on their revisit intention. The study proposes that motorsports marketers make use of olfactory stimuli to provide racing spectators with memorable experiences.

Traditional B‐staged epoxy film adhesives have been used as substrate attach adhesive for hybrid circuits. The advantages of using film adhesive instead of paste adhesive are precise bond‐line, clean operation, ease of application for larger bonding area and possibility to automate the process for large volume production. Epoxy, in general, is more stable than polyurethane and is better in adhesion with no contamination problems in comparison with silicone. Traditional epoxy, however, has high bond strength and is therefore limited only to substrates with matched thermal expansion properties. Combining the advantages of excellent adhesion of epoxy and flexibility of rubbery substance, a low glass transition temperature (Tg) epoxy which is flexible in nature has been developed for bonding substrates with mis‐matched thermal expansion coefficient. The new epoxy adhesive is also designed to meet the requirements of MIL‐STD‐883C/5011 in application without sacrificing ionic purity, low outgassing, thermal conductivity and long‐term dielectric or conductive properties. The new flexible film adhesive, in both its insulating and conductive forms, has attracted new applications and designs that were not previously feasible. For example, the flexible film adhesive can be used to bond ceramic hybrids directly to a lower cost metal substrate such as aluminium or copper. Testing has been performed by users on the combination of alumina/aluminium for over 1000 thermal cyclings and shocks from −55 to 150°C for large area bonding (up to a maximum of 6 x 6 inches square). The cured flexible epoxy adhesive, while very pliable, also exhibits more than 1,000 to 2,000 psi lap‐shear strength (depending on the type of substrate) and withstands more than 15,000 g acceleration test.

The complexity of microelectronic circuits, their scale of integration and clock speed requirements have been increasing steadily. All these changes have the effect of increasing the power density of the microcircuits. ICs with a power of several watts and an area of over a square centimetre are quite common. Thus, there is more heat generated per device at die, component and substrate‐attach levels of electronic packaging. In order to maintain reliability of finished products, the junction temperature of the constituent devices must be kept low. It has been demonstrated that thermal management can be one key to lowering the cost and increasing the performance life of microelectronic products. The cost‐effectiveness of lowering device temperature has been demonstrated to be dramatic compared with the cost of thermal management materials. Proper thermal management of advanced microelectronic devices has to be addressed at all levels. One should address the problem from the basic level of die‐attach, through component‐attach, and eventually substrate‐attach to thermal drains. Thermal management is almost invariably coupled with a thermally induced stress problem. The increase in temperature at the device level also means a larger fluctuation of temperature from the ambient. Each cycle of on‐off for the device represents one thermal cycle. Stress‐induced failure due to coefficient of thermal expansion (CTE) mismatch is much more acute for higher power devices. In this paper, the authors address the issue of thermally induced stress on the microelectronic product at all levels of packaging, with major emphasis on component and substrate levels. Various ways and examples of reducing or eliminating this stress, which is a major cause of device failures, will be demonstrated. One of the proven methods is through the use of low Tg epoxies with high thermal stability.

This chapter focuses on practical considerations for organizations when endeavoring to invest in design, specifically how designers and their organizations should view their profession for the benefit of corporate innovation. Given the lack of consensus regarding what strategic design entails, the author interviewed strategic designers from across the United States to solicit their opinions on design thinking, strategic design, and design strategy, the relationship between those concepts, and how those concepts are, could be, and should be reflected in practice.

The overarching purpose of this chapter is to explore the relatively nascent profession of strategic design, from which the author distinguishes design strategy, as well as to provide guidance regarding how design and designers should be viewed and supported by the leadership of their organizations in order to fully empower them to support innovation. In addition, this chapter serves to better define the concepts of design thinking, strategic design, and design strategy. While design as a discipline is broad, for the sake of consistency, the author discusses design in the context of technological development and, in turn, in terms of human-computer interaction.

Dates: 29–31 May 1991 Venue: De Doelen Conference Centre, Rotterdam, The Netherlands The Benelux Chapter of the International Society for Hybrid Microelectronics will be organising the 8th European Microelectronics Conference. The event will take place at ‘De Doelen’, Rotterdam, The Netherlands, from 29 to 31 May 1991.

A novel 3D shape optimization algorithm is presented for electromagnetic devices carrying eddy current. The algorithm integrates the 3D finite element performance analysis and the steepest descent method with design sensitivity and mesh relocation method. For the design sensitivity formula, the adjoint variable vector is defined in complex form based on the 3D finite element method for eddy current problems. A new 3D mesh relocation method is also proposed using the deformation theory of the elastic body under stress to renew the mesh as the shape changes. The design sensitivity for the surface nodal points is also systematically converted into that for the design variables for the parameterized optimization application. The proposed algorithm is applied to the optimum design of the tank shield model of transformer and the effectiveness is proved.

This study aims to investigate whether the cash flow forecasts (CFF) of analysts can disseminate valuable information to the information environments of companies.

The author uses empirical archival methodology to conduct differences-in-difference analyses.

It is found that information asymmetry decreases in the treatment group following the initiation of CFF during the postperiod, which is consistent with the hypothesis of this paper.

To the best of the author’s knowledge, this study is the first among the cash flow forecast studies to demonstrate the usefulness of CFF in the mitigation of information asymmetry, a friction that is widespread in capital markets.

The study aims to assess the moderating role of celebrity characteristics in the relationship between celebrity endorsement and telecommunication companies’ reputation.

Analysis of results was based on 700 customers in the telecommunication sector. Confirmatory factor analysis was conducted to check for validity and reliability of the observed items. A hierarchical regression model was estimated to test the various hypotheses set for the study.

The study finds that celebrity endorsement in itself had no significant effect on the reputation of telecommunication companies. Celebrity attractiveness, likeability and trustworthiness had a direct effect (positive) on the reputation of telecommunication companies and positively moderated the effect of celebrity endorsement on telecommunication company reputation. Celebrity expertise had no direct effect on telecommunication company reputation but positively moderated the effect of celebrity endorsement and telecommunication company reputation.

This study was purely quantitative. Future study could consider a mixed approach and include senior management members of the telecom firms for an in-depth interview.

In signing on celebrities as brand ambassadors, management must pay particular attention to celebrity attractiveness, likeability and trustworthiness. This would be more rewarding to the firms.

The study adds to the little empirical knowledge available on celebrity endorsement in sub-Saharan Africa and telecommunication sector in particular.