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The research is directed at development of an efficient and accurate technique for modelling incompressible free surface flows in which viscous effects may not be neglected. The paper describes the methodology, and gives illustrative results for simple geometries.

The pseudospectral matrix element method of discretisation is selected as the basis for the CFD technique adopted, because of its high spectral accuracy. It is implemented as a means of solving the Navier‐Stokes equations coupled with the modified compressibility method.

The viscous solver has been validated for the benchmark cases of uniform flow past a cylinder at a Reynolds number of 40, and 2D cavity flows. Results for sloshing of a viscous fluid in a tank have been successfully compared with those from a linearised analytical solution. Application of the method is illustrated by the results for the interaction of an impulsive wave with a surface piercing circular cylinder in a cylindrical tank.

The paper demonstrates the viability of the approach adopted. The limitation of small amplitude waves should be tackled in future work.

The results will have particular significance in the context of validating computations from more complex schemes applicable to arbitrary geometries.

The new methodology and results are of interest to the community of those developing numerical models of flow past marine structures.

The purpose of this study is simulation of dynamic stall behavior around the Eppler 387 airfoil in the low Reynolds number flow with a direct-forcing immersed boundary (DFIB) numerical model.

A ray-casting method is used to define the airfoil geometry. The governing continuity and Navier–Stokes momentum equations and boundary conditions are solved using the DFIB method.

The purposed method is validated against numerical results from alternative schemes and experimental data on static and oscillating airfoil. A base flow regime and different vortices patterns are observed, in accordance with other previously published investigations. Also, the effects of the reduced frequency, the pitch oscillation amplitude and the Reynolds number are studied. The results show that the reduced frequency has a major effect on the flow field and the force coefficients of the airfoil. On the other hand, the Reynolds number of the flow has a little effect on the dynamic stall characteristics of the airfoil at least in the laminar range.

It is demonstrated that the DFIB model provides an accurate representation of dynamic stall phenomenon.

The results show that the dynamic stall behavior around the Eppler 387 is different than the general dynamic stall behavior understanding in the shedding phase.

The purpose of this study is to the modeling of the dielectric barrier discharge (DBD) actuator on the Eppler 387 (E387) airfoil in low Reynolds number conditions.

A validated direct-forcing immersed boundary method is used to solve the governing equations. A linear electric field model is used to simulate the DBD actuator. A ray-casting technique is used to define the geometry.

The purposed model is validated against the former studies. Next, the drag and lift coefficients in the static stall of the E387 airfoil are investigated. Results show that when the DBD actuator is on, both of the coefficients are increased. The effects of the location, applied voltage and applied frequency are also studied and find that the leading-edge actuator with higher voltage and frequency has better improvement in the forces. Finally, the dynamic stall of the E387 with the DBD actuator is considered. The simulation shows that generally when the DBD is on, the lift coefficient in the pitch-up section has lower values and in the pitch-down has higher values than the DBD off mode.

It is demonstrated that using the DBD actuator on E387 in the low Reynolds number condition can increase the lift and drag forces. Therefore, the application of the airfoil must be considered.

The results show that sometimes the DBD actuator has different effects on E387 airfoil in low Reynolds number mode than the general understanding of this tool.

The purpose of this paper is to review and analyze the perishable inventory models along various dimensions such as its evolution, scope, demand, shelf life, replenishment policy, modeling techniques and research gaps.

In total, 418 relevant and scholarly articles of various researchers and practitioners during 1990-2016 were reviewed. They were critically analyzed along author profile, nature of perishability, research contributions of different countries, publication along time, research methodologies adopted, etc. to draw fruitful conclusions. The future research for perishable inventory modeling was also discussed and suggested.

There are plethora of perishable inventory studies with divergent objectives and scope. Besides demand and perishable rate in perishable inventory models, other factors such as price discount, allow shortage or not, inflation, time value of money and so on were found to be combined to make it more realistic. The modeling of inventory systems with two or more perishable items is limited. The multi-echelon inventory with centralized decision and information sharing is acquiring lot of importance because of supply chain integration in the competitive market.

Only peer-reviewed journals and conference papers were analyzed, whereas the manuals, reports, white papers and blood-related articles were excluded. Clustering of literature revealed that future studies should focus on stochastic modeling.

Stress had been laid to identify future research gaps that will help in developing realistic models. The present work will form a guideline to choose the appropriate methodology(s) and mathematical technique(s) in different situations with perishable inventory.

The current review analyzed 419 research papers available in the literature on perishable inventory modeling to summarize its current status and identify its potential future directions. Also the future research gaps were uncovered. This systemic review is strongly felt to fill the gap in the perishable inventory literature and help in formulating effective strategies to design of an effective and efficient inventory management system for perishable items.

The purpose of this study is to determine simultaneously the period of preventive maintenance and the sequence of each job for two parallel machines problem so that the makespan is minimized. With proper planning of preventive maintenance, a shop can avoid lack of flexibility between maintenance planning and production scheduling, and thus concentrate on production efficiency.

This study addresses a scheduling problem, wherein each machine has to be shut down for maintenance during a maintenance interval [C, T] arranged in advance. The start time and end time of the preventive maintenance are the decision variables. A maintenance action is attended by a server who managers only one machine at a time. Three cases are studied in this paper: the unequal lengths of unavailable periods on both machines, the equal lengths of unavailable periods on both machines, and no waiting time is allowed between the two unavailable periods. Each case is solved optimally by an analytical algorithm developed in the study.

Although having exponential time complexities, all the proposed algorithms are quite efficient in solving large‐sized problems. Computational results show that it is able to generate the optimal solution for large sizes (up to 10,000 jobs) in a few minutes of computation time.

Most of the papers that dealt with preventive maintenance assumed that the maintenance period is known and specified. However, the flexible preventive maintenance problem, in which the start time and end time of the preventive maintenance are the decision variables, often occurs in the computer center, NC‐machine and IC‐testing machine for job scheduling and repairs arrangement.

The paper presents an efficient approach for each of the three cases of flexible preventive maintenance, which is relatively unexplored in the literature.

Globe valves have good throttling ability, which permits its use in regulating flows. This paper aims to understand in detail the globe valve with different cage configurations and its impact on the flow characteristics that was carried out.

The computational study was carried out using FLUENT, a finite volume-based numerical code. Grid sensitivity tests were done and the results were validated experimentally. The effect of cage configuration on flow characteristics and valve coefficient was studied and optimised.

Valve coefficient was found to be dependent on cage configuration and reaches its maximum for the valve with triangular shaped aperture. Methodology to improve flow performance of a globe valve with highest valve coefficient is established.

Studies related with caged-type globe valves having different configurations are useful for improving their flow performance. In the present investigation, globe valves with different cage configurations and throttle positions are modeled to find out the valve coefficient, pressure and velocity contours inside and outside the cage and is validated with experimental results.

This paper aims to develop efficient decision support tools for a firm’s environment protection by using greening effort while yet improving profitability by utilizing pricing and inventory decisions with discount consideration.

This study proposed a mathematical model for price- and greening effort-dependent demand rate with discount considerations. Later, the mathematical model is extended to the situation in which the demand rate is also dependent on the stock level, in addition to the price and greening effort. Efficient solution methodologies are developed for finding the optimal solution to the proposed models.

Simple yet elegant models are proposed to mimic real-life applications. Structural properties of the models are explored to outline efficient algorithms with quantity discounts.

The paper considers monopoly and assumes deterministic demand. Only a more commonly observed all-units discount scheme is studied.

The models provide decision support tools for firms in pursuit of joint profit maximization and environment consciousness goals.

The study develops environment-friendly approaches for inventory management and improving the profitability alike.

This study is among the first to consider environmental protection with an investment in greening effort along with inventory management and pricing decision. The study also explored the effect of all-unit quantity discounts.

The purpose of this paper is to investigate the mechanism of sheets ply separation induced by air flow through numerical simulation with two-way FSI (fluid-structure interaction) simulation using ANSYS and theoretical speculation.

The paper primarily establishes a simplified physical model of the sheets ply separation induced by air flow. Then, the force of the air flow acting on the sheet has been analyzed based on the model, and the main factor leading to separation was obtained. Furthermore, the parameter analysis was investigated based on linear stability analysis, from which the factors that affect stable separation are obtained. Finally, a series of numerical simulations are performed to verify the conclusions.

This study shows that the main separation factor is the variable air pressure in the gap between the sheets caused by the dynamic pressure air flow. Increasing the inlet velocity of the flow field will increase the separation distance but excessive velocity will lead to instability. The viscous resistance acting on the sheet and the bending stiffness of the sheet are factors that stabilize the system, and the sheet density and the restoring force can lead to instability.

The paper is one of the first in the literature that investigates the problem of sheets ply separation induced by air flow, which is the primary method for multi-layer separation in sheets de-stacking operations, especially for the high-speed occasion.

Manufacturing firms are expected to implement green manufacturing and increase product complexity at a competitive price. However, a major problem for engineering managers is to ascertain the costs of embarking on green manufacturing. Thus, a planning and control methodology for costing of green manufacturing at the early design stage is important for engineering managers. The paper aims to discuss these issues.

This paper integrates “green manufacturing,” concepts of industrial dynamics, and product lifecycle aiming at developing a methodology for cost calculation. The methodology comprises of a process-based cost model and a systems dynamics (SD) model. The process-based cost model focusses mainly on carbon emission costs and energy-saving activities. Important metrics usually ignored in traditional static modeling were incorporated using SD model.

Equipment costs and carbon emission costs are major components of costs in manufacturing. The total life cycle cost of product in green manufacturing is lower than that of same product in conventional manufacturing.

The specific results of this study are limited to the case company, but can hopefully contribute to further research on ascertaining cost of implementing “green issues” in manufacturing. The proposed cost calculation model can be efficiently applied in any manufacturing firm on the basis of accessibility of real cost data. This necessitates a comprehensive cost database. At the development of the model and database management system, time and cost resources could be demanding, but once installed, use of the model becomes less demanding.

The cost model provides cost justifications of implementing green manufacturing. The reality is that green manufacturing will see its development peak with cost justifications. The results of the application show that the proposed detailed cost model can be effective in ascertaining costs of implementing green manufacturing. Manufacturing firms are recommended to adopt energy-saving activities based on the proposed detailed cost calculation model.

The main contributions of the study includes: first, to help engineering managers more accurately understand how to allocate resources for energy-saving activities through appropriate cost drivers. Second, to simulate with SD the dynamic behavior of few important metrics, often ignored in traditional mathematical modeling. The detailed model provides a pre-manufacturing decision-making tool which will assist management in implementing green manufacturing by incorporating a life cycle assessment measurement into manufacturing cost management.

One of the best methods to improve wind turbine aerodynamic performance is modification of the blade’s airfoil. The purpose of this paper is to investigate the effects of gurney flap geometry and its oscillation parameters on the pitching NACA0012 airfoil.

This numerical solution has been carried out for different cases of gurney flap mounting angles, heights, reduced frequencies and oscillation amplitudes, then the results were compared to each other. The finite volume method was used for the discretization of the governing equations, and the PISO algorithm was used to solve the equations. Also, the “SST” was adopted as the turbulence model in the simulation.

In this paper, the different parameters of gurney flap were investigated. The results showed that the best range of gurney flap height are between 1 and 3.2% of chord and the best ratio of lifting to drag coefficient is achieved in gurney flap with an angle of 90° relative to the chord direction. The dynamic stall angle of the airfoil with gurney flap decreases were compared to without gurney flap. Earlier LEV formation can be one of the main reasons for decreasing the dynamic stall angle of the airfoil with gurney flap. Increasing the reduced frequency and oscillation amplitude causes rising of maximum lift coefficient and consequently lift curve slope. Moreover, gurney flap with mounting angle has a lower hinge moment than the gurney flap without mounting angle but with the same vertical axis length. So, there is more complexity in structural design concerning the gurney flap without mounting angle.

Improving aerodynamic efficiency of airfoils is vital for obtaining more output power in VAWTs. Gurney flaps are one of the best mechanisms to increase the aerodynamic performance of the airfoil and increases the efficiency of VAWTs.

Investigating the hinge moment on the connection point of the airfoil, gurney flap and try to compare the gurney flap with and without angle.