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The special structure of the vortex pump contributes to its complex internal flow pattern. A type of horizontal 150WX-200-20 vortex pump is taken as a research subject to deeply study the progression and distribution of flow pattern in its channel. To explain the mechanism of flow in this pump, numerical analysis of the whole flow and experiment have been conducted.

The authors studied and analyzed the distribution and evolution of flow pattern under different flow, such as circulating-flow, through-flow and other forms. Finally, a model of flow pattern in the vortex pump has been built, which has more perfectly fit the reality.

They are through-flow affected by circulating-flow, main and subsidiary circulating-flow, vortices between vanes and other vortices (or liquid impingement) in volute. Entering the pump, part of the flow stays in vanes and turn into vortices while the other goes into the front chamber. The flow that runs into the front chamber will be divided into two parts. One part will be collected by viscosity into a vortex rope when it passing through the interface between the impeller and the vaneless chamber, which closely relates to the circulating-flow, and the rest directly goes out of the field through the diffuser. Besides, a fraction of circulating-flow joins the through-flow when it goes through the section V and leaves the pump.

The research results build a theoretical foundation for working out the flow mechanism of the vortex pump, improving its efficiency and optimizing its hydraulic design.

The purpose of this paper is to simulate the behaviour of the symmetrical turn‐up vortex amplifier (STuVA) to obtain insight into its maximum through‐flow operation within the eight‐port STuVA, and understand the relation between its design parameters and flow characteristics. Furthermore, it is to test the performance of different turbulent models and near‐wall models using the same grid, the same numerical methods and the same computational fluid dynamics code under multiple impingement conditions.

Three turbulence models, the standard k‐ε, the renormalization group (RNG) k‐ε model and the Reynolds stress model (RSM), and three near‐wall models have been used to simulate the confined incompressible turbulent flow in an eight‐port STuVA using unstructured meshes. The STuVA is a special symmetrical design of turn‐up vortex amplifier, and the simulation focused on its extreme operation in the maximum flow state with no swirling. The predictions were compared with basic pressure‐drop flow rate measurements made using air at ambient conditions. The effect of different combinations of turbulence and near‐wall models was evaluated.

The RSM gave predictions slightly closer to the experimental data than the other models, although the RNG k‐ε model predicted nearly as accurately as the RSM. They both improved errors by about 3 per cent compared to the standard k‐ε model but took a long time for convergence. The modelling of complex flows depends not only on the turbulence model but also on the near‐wall treatments and computational economy. In this study a good combination was the RSM, the two layer wall model and the higher order discretization scheme, which improved accuracy by more than 10 per cent compared to the standard k‐ε model, the standard wall function and first order upwind.

The results of this paper are valid for the global pressure drop flow rate. It should be desirable to compare some local information with the experiment.

This paper provides insight into the maximum through‐flow operation within the eight‐port STuVA to understand the relation between its design parameters and flow characteristics and study the performance of turbulence and near wall models.

The paper seeks to perform a detailed numerical study of flow over a generic fan‐wing airfoil and also attempts to modify the geometry for the improvement of the aerodynamic performance.

Advanced computational fluid dynamics (CFD) technique has been employed for evaluation of the aerodynamic performance (e.g. lift/drag ratio) of a model problem. Numerical investigation starts with sensitivity studies to minimize domain size influence and grid dependency, followed by time‐accurate transient calculations. A preliminary re‐design exercise has been performed by analyzing the results of a current design.

CFD predicted lift force agrees fairly well with the measurement data with about 6.55 per cent error, while drag force compares less favourably with about 12.59 per cent error. Both errors are generally acceptable for an engineering application of complex flow problems. Several key flow features observed previously by experiment have also been re‐produced by simulation, notably the eccentric vortex motions in the blade interior and the stream “jet” flow outside the blades near the exit. With the modified geometry, there is a considerable lift/drag ratio improvement of about 29.42 per cent. The possible reasons for such a significant improvement have been discussed.

As it is the first step towards the detailed flow analysis of this type of model, a simpler blade shape rather than “real” one has been used.

The paper provides a very useful source of information and could be used as guidance for further industry practice of unmanned aerial vehicles design.

This paper is valuable for both academic researchers and industry engineers, especially those working in the area of high‐lift wing design. The works presented are original.

This paper aims to conduct the optimization of the multi-stage gas turbine with the effect of the cooling air injection based on the adjoint method.

Continuous adjoint method is combined with the S2 surface code.

The optimization of the stagger angles, stacking lines and the passage can improve the attack angles and restrain the development of the boundary, reducing the secondary flow loss caused by the cooling air injection.

The aerodynamic performance of the gas turbine can be improved via the optimization of blade and passage based on the adjoint method.

The results of the first study on the adjoint method applied to the S2 surface through flow calculation including the cooling air effect are presented.

This study aims to ascertain the role of servant leadership in inducing flow at work. The study, along with confirming the relation between flow at work and innovative work behavior (IWB), intends to explore the mediating role flow at work plays in relating servant leadership to IWB.

The data collection was conducted through an interviewee-administered questionnaire in three waves that were four weeks apart. The data were collected from 267 respondents. To run the measurement model and structural model, Smart-PLS was used, and Statistical Product and Service Solutions (SPSS) was used to summarize the demographic information and conduct hierarchal regression.

Servant leadership is related to flow at work. Additionally, flow at work is related to IWB. Finally, flow at work mediates the relationship between servant leadership and IWB.

The study found servant leadership is related to flow at work. Moreover, the study unearthed the relation between flow at work and IWB. Finally, the study unveiled that flow at work acts as a mediator between servant leadership and IWB.

Having read previous literature about vortex pump, we noticed that mechanisms of circulating flow and its relationship with energy transition remain unclear yet. However, this mechanism, which should be clarified, significantly influences the pump’s efficiency. To comply with the aim of investigating it, the 150WX-200-20 type pump is selected as study object in our present work.

Numerical simulation is conducted to formulate interactions between flow rate and geometric parameters of circulating flow with certain types of blade while experiments on inner flow are served as a witness to provide experimental confirmation of numerical results. Based on these, we coupled some parameters with the pump’s external performance to study their internal connections.

It is concluded that separatrix between circulating flow and other turbulent forms is not that clear under low flow rate. With flow increases, hydraulic losses coming of it will be dominant within the front chamber. Besides, we analogized circulating flow to vortices so as to make a quantitative analysis on its progressive evolution with changing flow, and vortices speaking for circulating flow can be divided into two groups. One is called main circulating flow vortex (hereinafter referred to as MCFV), which occurs all the time while subsidiary circulating flow vortices (hereinafter referred to as SCFV) appear in certain conditions. This context discusses the primary phase of our work with intent to follow up further with circulating flow characterized by vortices (hereinafter referred to as CFV). We confirmed that MCFV Vortex 1 (Vor1) directly influences the efficiency while SCFVs only play helping. As the flow goes to the given working condition, fluids in this pump tend to be steady with the size of CFVs getting larger and their shape being regular. Meanwhile, for MCFV Vor2 and Vor4, their geometric parameters are the key factors for efficiency. When CFVs become steady, they absorb other vortices nearby, as they have higher viscosity with the efficiency reaching its maximum.

The research results explore a new way to measure the circulating flow and help work out the causation of this flow pattern, which may be used to improve the vortex pump’s efficiency.

In an era of burgeoning activity in online retail in India, the role of web-store design is paramount. Web-store design elements such as website functionality, brand assortment and product quality are expected to generate customer loyalty.

Using data collected from 553 students from two universities in north India, the present study investigates the indirect effect of web-store dimensions (through website functionality, brand assortment and product quality) on online store loyalty via an enjoyment state (flow) and customer satisfaction. Serial mediation has been analysed through PROCESS macro developed by Hayes version 3.0. In addition to this, the moderating role of gender and purchase frequency has also been investigated.

The present study renders support to serial mediation between website functionality, flow, customer satisfaction and loyalty. However, the path between brand assortment and loyalty is more strongly mediated by customer satisfaction only. Males experience less flow as compared to females while handling brand assortment on websites. The three-way interaction between brand assortment, gender and purchase frequency is also statistically significant.

The study examines the manner in which online retailers can choose to build customer loyalty when they try to build retail image using web store functionality and /or product/brand assortments. The study offers insights to retailers about how and when to focus on hedonism versus customer satisfaction or both of them in conjunction to enhance customer loyalty. This study is important as it investigates the relationships in Indian scenario witnessing a high rate of growth in online retail which can tremendously affect these relationships.

The main objective of this study was to obtain the flow restricting capacity by determining their flow coefficients and to investigate the unsteady flow with low Reynolds number in the flow‐restricting devices such as orifices and capillary tubes having small diameters.

There is an enormous literature on the flow of Newtonian fluids through capillaries and orifices particularly in many application fields of the mechanical and chemical engineering. But most of the experimental results in literature are given for steady flows at moderate and high Reynolds numbers (Re>500). In this study, the unsteady flow at low Reynolds number (10<Re<650) through flow‐restricting devices such as orifices and capillary tubes having very small diameters between 0.35 and 0.70 mm were experimentally investigated.

The capillary tubes have much more capillarity property with respect to equal diameter orifices. Increasing the ratio of capillary tube length to tube diameter and decreasing the ratio of orifice diameter to pipe diameter before orifice increase the throttling or restricting property of the orifices and the capillary tubes. The orifices can be preferred to the capillary tubes having the same diameter at the same system pressure for the hydraulic systems or circuits requiring small velocity variations. The capillary tubes provide higher pressure losses and they can be also used as hydraulic accumulators in hydraulic control devices to attenuate flow‐induced vibrations because of their large pressure coefficients. An important feature of the results obtained for capillary tubes and small orifices is that as the d/D for orifices increases and the L/d reduces for capillary tubes, higher values C are obtained and the transition from viscous to inertia‐controlled flow appears to take place at lower Reynolds numbers. This may be explained by the fact that for small orifices with high d/D ratios and for capillary tubes with small L/d ratios, the losses due to viscous shear are small. Another important feature of the results is that the least variations in C for small orifices and the higher variations in C for capillary tubes occur when the d/D and L/d ratios are smallest. This has favourable implications in hydraulic control devices since a constant value for the C may be assumed even at relatively low values of Re.

To the authors' knowledge, there is not enough information in the literature about the flow coefficients of unsteady flows through capillary tubes and small orifices at low Reynolds numbers. This paper fulfils this gap.

Based on narrative theory, emotional contagion theory, and anticipated emotions theory, the purpose of this paper is to adopt an experimental design intended to understand how narrative advertising video on internet, narrator flow and online audience characteristics influence the health communication effects and depression prevention messages of public service advertisements.

This study uses two experimental designs. The first contrasts the effectiveness of persuasion between narrative and argument advertising videos on internet, while the second contrasts the effectiveness of persuasion between narrators with high and low flow. This study employed partial least squares path modeling to validate the research structure hypothesis.

Empirical results indicate that internet narrative advertising video is not direct, but rather draws on flow and positive anticipated emotions to stimulate the production of online audience intention to adopt health risk-reducing behaviors. Compared with narrative advertising video, which influences intention to adopt health risk-reducing behaviors through flow and positive anticipated emotions, narrator advertising video with an emotionally invested high-flow narrator can strengthen online audience intention to adopt risk-reducing behaviors more directly and positively.

The study results can provide elements to assist in the design of online advertising video on depression prevention and health promotion.

In this study, the dialogue among narrative theory, emotional contagion theory, and anticipated emotions theory is constructed, and an integrated conceptual framework is developed for the relationship between internet advertising video type and the health communication.

The purpose of this paper is to investigate users’ continuous adoption behaviors on mobile game playing from the perspective of situational habit formation.

Based on the literature research, a continuous adoption model for situational mobile game is proposed. And the research model is assessed based on data gathered from a sample of 226 mobile game players by employing the structural equation model methodology.

The results show that situational cues represented by availability, perceived ease of use and diversion lead to repeated performance that can be represented by flow experience and satisfaction in the situational mobile game playing context. But only flow experience and diversion influence continuous usage directly. Additionally diversion, as a critical situational variable, not only indirectly affects continuous usage intention through flow experience, but also directly affects continuous usage intention for situational mobile game playing.

Mobile game adoption has been studied from different perspectives, but most research is based on the technology acceptance model. They could not explain the common fact that young people tend to be highly motivated by mobile games and can be regarded as pro-active mobile game players, but many people play mobile games only when they are bored and need a diversion. So this study attempts to illustrate the phenomena to fill the gaps.