Salman Arshad, Bo Kong, Alan Kerstein and Michael Oevermann
The purpose of this numerical work is to present and test a new approach for large-scale scalar advection (splicing) in large eddy simulations (LES) that use the linear eddy…
Abstract
Purpose
The purpose of this numerical work is to present and test a new approach for large-scale scalar advection (splicing) in large eddy simulations (LES) that use the linear eddy sub-grid mixing model (LEM) called the LES-LEM.
Design/methodology/approach
The new splicing strategy is based on an ordered flux of spliced LEM segments. The principle is that low-flux segments have less momentum than high-flux segments and, therefore, are displaced less than high-flux segments. This strategy affects the order of both inflowing and outflowing LEM segments of an LES cell. The new splicing approach is implemented in a pressure-based fluid solver and tested by simulation of passive scalar transport in a co-flowing turbulent rectangular jet, instead of combustion simulation, to perform an isolated investigation of splicing. Comparison of the new splicing with a previous splicing approach is also done.
Findings
The simulation results show that the velocity statistics and passive scalar mixing are correctly predicted using the new splicing approach for the LES-LEM. It is argued that modeling of large-scale advection in the LES-LEM via splicing is reasonable, and the new splicing approach potentially captures the physics better than the old approach. The standard LES sub-grid mixing models do not represent turbulent mixing in a proper way because they do not adequately represent molecular diffusion processes and counter gradient effects. Scalar mixing in turbulent flow consists of two different processes, i.e. turbulent mixing that increases the interface between unmixed species and molecular diffusion. It is crucial to model these two processes individually at their respective time scales. The LEM explicitly includes both of these processes and has been used successfully as a sub-grid scalar mixing model (McMurtry et al., 1992; Sone and Menon, 2003). Here, the turbulent mixing capabilities of the LES-LEM with a modified splicing treatment are examined.
Originality/value
The splicing strategy proposed for the LES-LEM is original and has not been investigated before. Also, it is the first LES-LEM implementation using unstructured grids.
Details
Keywords
Since the 80s of the last century in German Sociology, a discussion has taken place referring to the question of the persistence of class‐related social inequality or new…
Abstract
Since the 80s of the last century in German Sociology, a discussion has taken place referring to the question of the persistence of class‐related social inequality or new socio‐cultural concepts, such as life‐style of social milieu, in order to describe and analyse different patterns of attitudes and behavior. However, it would be more fruitful to analyse fields where class or life‐style are more appropriate in describing the segmentation of the social world. In this article, we address the question whether different choices of holidays can better be predicted by a measure of social class or a life‐style typology, developed on the basis of different dimensions of everyday taste. As a result, it can be shown that the predictive power of life‐style in the field of holiday behavior is about three times as strong as social class.
Carl Marcus Wallenburg and Peter Lukassen
The purpose of this paper is to provide a differentiated view of relationship‐specific proactive improvement of logistics service providers (LSPs) that distinguishes between the…
Abstract
Purpose
The purpose of this paper is to provide a differentiated view of relationship‐specific proactive improvement of logistics service providers (LSPs) that distinguishes between the cost and performance and the effect that these two dimensions of innovation have on three distinct customer loyalty dimensions (retention, extension, and referrals).
Design/methodology/approach
A confirmatory empirical study was conducted based on social exchange theory and customer value theory. The survey responses from 298 firms were analysed using structural equation modelling and multi‐group analysis to test for direct effects and moderation.
Findings
Both dimensions of relationship‐specific proactive improvement by LSPs (cost and performance) are strong drivers of all three customer loyalty dimensions and, thus, are important to customer relationship management and relevant areas to be considered within innovation management. The effect on customer loyalty is moderated by the dynamism of the customer's market. Proactive cost improvements are more important under high dynamism, while proactive performance improvements, contrary to initial assumptions, are more important when dynamism is low.
Research limitations/implications
Future studies should analyse other cultural settings, differentiate between functional and relationship value provided, consider other services, investigate how LSPs can facilitate proactive improvement and improve innovation management, and explore how customers can foster proactive improvement.
Practical implications
The currently low level of proactive improvement should be increased if LSPs want to enhance customer loyalty. In doing so, LSPs ought to consider the dynamism of their customers' markets.
Originality/value
The paper is the first to provide a differentiated view on the role of relationship‐specific proactive innovation that distinguishes between cost and performance improvements and illustrates their effects on three distinct customer loyalty dimensions.