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Article

Alankrita Singh, Balaji Chakravarthy and BVSSS Prasad

Numerical simulations are performed to determine the heat transfer characteristics of slot jet impingement of air on a concave surface. The purpose of this paper is to…

Abstract

Purpose

Numerical simulations are performed to determine the heat transfer characteristics of slot jet impingement of air on a concave surface. The purpose of this paper is to investigate the effect of protrusions on the heat transfer by placing semi-circular protrusions on the concave surface at several positions. After identifying appropriate locations where the heat transfer is a maximum, multiple protrusions are placed at desired locations on the plate. The gap ratio, curvature ratio (d/D) and the dimensions of the plate are varied so as to obtain heat transfer data. The curvature ratio is varied first, keeping the concave diameter (D) fixed followed by a fixed slot width (d). A surrogate model based on an artificial neural network is developed to determine optimum locations of the protrusions that maximize the heat transfer from the concave surface.

Design/methodology/approach

The scope and objectives of the present study are two-dimensional numerical simulations of the problem by considering all the geometrical parameters (H/d, dp, Re, θ) affecting heat transfer characteristics with the help of networking tool and numerical simulation. Development of a surrogate forward model with artificial neural networks (ANNs) with a view to explore the full parametric space. To quantitatively ascertain if protrusions hurt or help heat transfer for an impinging jet on a concave surface. Determination of the location of protrusions where higher heat transfer could be achieved by using exhaustive search with the surrogate model to replace the time consuming forward model.

Findings

A single protrusion has nearly no effect on the heat transfer. For a fixed diameter of concave surface, a smaller jet possesses high turbulence kinetic energy with greater heat transfer. ANN is a powerful tool to not only predict impingement heat transfer characteristics by considering multiple parameters but also to determine the optimum configuration from many thousands of candidate solutions. A maximum increase of 8 per cent in the heat transfer is obtained by the best configuration constituting of multiple protrusions, with respect to the baseline smooth configuration. Even this can be considered as marginal and so it can be concluded that first cut results for heat transfer for an impinging jet on a concave surface with protrusions can be obtained by geometrically modeling a much simpler plain concave surface without any significant loss of accuracy.

Originality/value

The heat transfer during impingement cooling depends on various geometrical parameters but, not all the pertinent parameters have been varied comprehensively in previous studies. It is known that a rough surface may improve or degrade the amount of heat transfer depending on their geometrical dimensions of the target and the rough geometry and the flow conditions. Furthermore, to the best of authors’ knowledge, scarce studies are available with inclusion of protrusions over a concave surface. The present study is devoted to development of a surrogate forward model with ANNs with a view to explore the full parametric space.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 31 no. 1
Type: Research Article
ISSN: 0961-5539

Keywords

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Article

Balaji S. Chakravarthy

There is a recurring theme in the spectacular successes of a Wal‐Mart in the U.S., a Canon in Japan, or an ISS in Europe: the ability to stake out future opportunities and…

Abstract

There is a recurring theme in the spectacular successes of a Wal‐Mart in the U.S., a Canon in Japan, or an ISS in Europe: the ability to stake out future opportunities and make preemptive commitments to a competence platform. Commitment begets success. Being a first mover is becoming a necessary condition for success.

Details

Strategy & Leadership, vol. 24 no. 3
Type: Research Article
ISSN: 1087-8572

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Article

Balaji S. Chakravarthy and Edward J. Zajac

The choice of proper incentives is a critical step in designing strategic planning systems. Incentives should integrate the behavior and action of managers with the…

Abstract

The choice of proper incentives is a critical step in designing strategic planning systems. Incentives should integrate the behavior and action of managers with the objectives and strategies of their firms. The problem of inappropriate incentives in various types of organizations has been described by Kerr. While the literature on incentives is voluminous, the linkage between incentives and strategic planning has not been carefully explored. We propose a model that connects a firm's incentive systems with its strategic context, using incentives theory in the economics literature as basic building blocks.

Details

Planning Review, vol. 12 no. 6
Type: Research Article
ISSN: 0094-064X

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Article

Balaji S. Chakravarthy

This article provides a framework for strategic adaptation toderegulation drawing on the lessons learned in the United States. A firmcan adapt to deregulation by the mix…

Abstract

This article provides a framework for strategic adaptation to deregulation drawing on the lessons learned in the United States. A firm can adapt to deregulation by the mix of productmarket and domain management strategies that it chooses. The strategies open to a firm in turn depend upon its resource endowment and strategic predisposition. Since it is difficult to alter either of these at short notice, it is imperative that a firm that is faced with deregulation in its environment initiates these transformations in anticipation of change.

Details

Journal of Organizational Change Management, vol. 4 no. 1
Type: Research Article
ISSN: 0953-4814

Keywords

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Article

Balaji S. Chakravarthy and Peter Lorange

If strategic planning systems have failed it is because managershave failed to adapt them to the changed contexts of their businesses.Four distinct contexts are…

Abstract

If strategic planning systems have failed it is because managers have failed to adapt them to the changed contexts of their businesses. Four distinct contexts are identified: Pioneer, Expand, Reorient, and Dominate. These labels are chosen to indicate the primary challenge for the business unit in each of these contexts. The contexts vary in their risk and in the adaptation and/or integration orientation that they demand of the strategic planning system. Four key elements of the strategic planning system: direction of goal setting, time‐spending patterns in planning, the relative importance of the strategic budget, and the linkage between the financial plan and the budgets, are identified. Each can be manipulated to adapt the system to suit the firm′s business context.

Details

Journal of Organizational Change Management, vol. 4 no. 2
Type: Research Article
ISSN: 0953-4814

Keywords

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Article

Srinivasa Ramanujam, R. Chandrasekar and Balaji Chakravarthy

The purpose of this paper is to develop an algorithm, using PCA‐based neural network, to retrieve the vertical rainfall structure in a precipitating atmosphere. The…

Abstract

Purpose

The purpose of this paper is to develop an algorithm, using PCA‐based neural network, to retrieve the vertical rainfall structure in a precipitating atmosphere. The algorithm is powered by a rigorous solution to the plane parallel radiative transfer equation for the atmosphere with thermodynamically consistent vertical profiles of humidity, temperature and cloud structures, together with “measured” vertical profiles of the rain structure derived from a radar.

Design/methodology/approach

The raining atmosphere is considered to be a plane parallel, radiatively participating medium. The atmospheric thermodynamic profiles such as pressure, temperature and relative humidity along with wind speed at sea surface and cloud parameters corresponding to Nargis, a category 4 tropical cyclone that made its landfall on May 2, 2008 at the Republic of Myanmar, are obtained by solving the flux form of Euler's equations in three‐dimensional form. The state‐of‐the‐art community software Weather Research and Forecasting has been used for solving the set of equations. The three‐dimensional rain profiles for the same cyclone at the same instant of time are obtained from National Aeronautics and Space Administration's space borne Tropical Rainfall Measuring Mission's precipitation radar over collocated pixels. An in‐house Micro‐Tropiques code is used to perform radiative transfer simulations for frequencies corresponding to a typical space borne radiometer, and hence to generate the database which is later used for training the neural network. The back propagation‐based neural network is optimized with reduced number of parameters using principal component analysis (PCA).

Findings

The results show that neural network is capable of retrieving the vertical rainfall structure with a correlation coefficient of over 0.99. Further, reducing the ill‐posedness in retrieving 56 parameters from just nine measurements using PCA has improved the root mean square error in the retrievals at reduced computational time.

Originality/value

The paper shows that combining numerically generated atmospheric profiles together with radar measurements to serve as input to a radiative transfer model brings in the much‐required synergy between numerical weather prediction, radar measurements and radiative transfer. This strategy can be gainfully used in satellite meteorology. Using principal components to reduce the ill‐posedness, thereby increasing the robustness in retrieving vertical rain structure, has been attempted for the first time. A well‐trained network can be used as one possible option for an operational algorithm for the proposed Indian climate research satellite Megha‐Tropiques, due to be launched in early 2011.

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Article

Audhesh K. Paswan

This study empirically explores one of the important channel issues – the relationship between various channel support given to channel partners and the perceived (by…

Abstract

This study empirically explores one of the important channel issues – the relationship between various channel support given to channel partners and the perceived (by managers) goal‐orientation of a firm. Results from an emerging market, India, indicate that perceived orientation towards both profitability and market share is not associated with any of the channel support considered. Growth orientation however is strongly associated with most of the channel support activities – both business (e.g., business advice, pricing and ordering assistance, and personnel training) as well as marketing (advertising support, sales promotional material, and inventory management assistance) oriented activities. In contrast, perceived sales volume orientation is only associated with advertising support and business advice, however, the relationship is negative. These findings have interesting implications for channel management and channel motivation.

Details

Asia Pacific Journal of Marketing and Logistics, vol. 15 no. 4
Type: Research Article
ISSN: 1355-5855

Keywords

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Article

Pradeep A. Rau and John F. Preble

This paper presents an analysis of the current debate on “global marketing” and the degree to which multinational firms can standardise their marketing practices across…

Abstract

This paper presents an analysis of the current debate on “global marketing” and the degree to which multinational firms can standardise their marketing practices across countries. World markets are getting increasingly homogenised but the authors contend that the framework and associated propositions generated in the paper could help multinational firms determine the degree of standardisation that is possible in different markets.

Details

International Marketing Review, vol. 4 no. 3
Type: Research Article
ISSN: 0265-1335

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