Search results for: tourist flow
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 5033

Search results for: tourist flow

4943 Numerical Investigation of Flow Behaviour Across a Trapezoidal Bluff Body at Low Reynolds Number

Authors: Zaaraoui Abdelkader, Kerfah Rabeh, Noura Belkheir, Matene Elhacene

Abstract:

The trapezoidal bluff body is a typical configuration of vortex shedding bodies. The aim of this work is to study flow behaviour over a trapezoidal cylinder at low Reynolds number. The geometry was constructed from a prototype device for measuring the volumetric flow-rate by counting vortices. Simulations were run for this geometry under steady and unsteady flow conditions using finite volume discretization. Laminar flow was investigated in this model with rigid walls and homogeneous incompressible Newtonian fluid. Calculations were performed for Reynolds number range 5 ≤ Re ≤ 180 and several flow parameters were documented. The present computations are in good agreement with the experimental observations and the numerical calculations by several investigators.

Keywords: bluff body, confined flow, numerical calculations, steady and unsteady flow, vortex shedding flow meter

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4942 Tourism in the Information Age

Authors: Suleyman Karacor

Abstract:

The main purpose of this study is to investigate tourism marketing in the information age because of the importance and sensitivity. In the twenty-first century as a result of today's the increasing competition and product diversification in the tourism sector, tourism businesses must take into account exogenous variables such as new technological developments, commercial experience and consumer demand. In the information age, tourist product consumers tend to reserve their leisure time and expenditure on more active opportunities for different experiences instead of living the same experience again. Increasing the number of agents in the tourism sector, travel opportunities offering different experiences and more intensive use of modern technology helps to present diversification of leisure activities for tourists. From the perspective of tourists, travel costs are still important for buying the touristic products but maintaining a high level of tourist satisfaction is also of increasing importance. Tourists tend to prefer activities that add value. A real tourist product must be able to create value and new priorities for tourists. Therefore this study aims to review recent significant developments in international tourism marketing research and practices. To this end, this study reviews tourism marketing-focused articles.

Keywords: information age, tourism marketing, tourism marketing mix, management

Procedia PDF Downloads 395
4941 Anisotropic Approach for Discontinuity Preserving in Optical Flow Estimation

Authors: Pushpendra Kumar, Sanjeev Kumar, R. Balasubramanian

Abstract:

Estimation of optical flow from a sequence of images using variational methods is one of the most successful approach. Discontinuity between different motions is one of the challenging problem in flow estimation. In this paper, we design a new anisotropic diffusion operator, which is able to provide smooth flow over a region and efficiently preserve discontinuity in optical flow. This operator is designed on the basis of intensity differences of the pixels and isotropic operator using exponential function. The combination of these are used to control the propagation of flow. Experimental results on the different datasets verify the robustness and accuracy of the algorithm and also validate the effect of anisotropic operator in the discontinuity preserving.

Keywords: optical flow, variational methods, computer vision, anisotropic operator

Procedia PDF Downloads 840
4940 A Comparison of Short- and Long-Haul Vacation Tourists on Evaluation of Attractiveness: The Case of Hong Kong

Authors: Zhaoyu Chen

Abstract:

In this study, an attempt was made to find reasons why tourists go to particular attractions. Tourists may be either motivated by the attractions or simply make the choice to satisfy their needs and desires. Based on the attractions in Hong Kong, this research was conducted to explore the attraction-related concepts to discuss how the attraction system works. Due to the limited studies on exploring the attractiveness of attractions through tourist movement patterns, the study aims to evaluate such indicators to determine whether tourists are motivated by attractiveness or their own needs. The investigation is conducted through the comparison of different source markets - Mainland China, short haul markets (excluding Mainland China) and long haul markets. The latest finding of Departing Visitor Survey (DVS) implemented by the Hong Kong Tourism Board (HKTB) is employed for the analysis. Various tourist movement patterns are drawn from the practical data. The managerial implication to destination management organizations (DMOs) is suggested to better allocate attractions according to the needs of tourists.

Keywords: attractions, attraction system, Hong Kong, tourist movement patterns

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4939 Flow as a Positive Intervention for Post-Traumatic Stress Disorder

Authors: Sonal Khosla

Abstract:

A research is proposed in the present paper to explore the role of flow in coping with traumatic experiences and attaining post-traumatic growth. A grounded theory research is proposed to be carried by analyzing memoirs of people who have been through trauma. A pilot study was carried out on two memoirs of women who were held captive for over ten years and were sexually assaulted repeatedly. The role of flow in their coping experiences was explored by analyzing the books. Some of the flow activities that were used by them were- drawing and daydreaming. Their narratives show the evidence for flow as having cathartic and healing effects on them. Applicability of the findings can take two forms: 1. Flow can be applied as a preventive technique to help the people who are going through trauma, 2. Flow can be adopted into a positive intervention to help people suffering from PTSD.

Keywords: flow, positive intervention, PTSD, PTG

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4938 The 'Saudade' Market and the Development of Tourism in the Azores: An Analysis of Travel Preferences of Azorean Emigrants

Authors: Silvia Rocha, Flavio Tiago, Maria Teresa Tiago, Sandra Faria, Joao Couto

Abstract:

The Azores have a tourist potential that has been developing, especially after an increase in promotion and the liberalization of airspace. However, there is still a gap with regard to the understanding of tourists from North America. Previous studies referred to the existence of two basic types of touristic flows: Emigrants and locals. Looking to help fill this gap, a study of travelers from North America was conducted. Using cluster analysis, it was determined the existence of three segments: nostalgic, regular and frequent. The recognition of these three segments is important to determine the necessary adjustments in tourist offerings to this market.

Keywords: tourism, diaspora, nostalgia, culture

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4937 Numerical Analysis of Passive Controlled Turbulent Flow around a Circular Cylinder

Authors: Mustafa Soyler, Mustafa M. Yavuz, Bulent Yaniktepe, Coskun Ozalp

Abstract:

In this study, unsteady two-dimensional turbulent flow around a circular cylinder and passive control of the flow with groove on the cylinder was examined. In the CFD analysis, solutions were made using turbulent flow conditions. Steady and unsteady solutions were used in turbulent flow analysis. Numerical analysis of the flow around the circular cylinder is difficult since flow is not in a stable regime when Reynold number is between 1000 and 10000. The analyses in this study were performed at a subcritical Re number of 5000 and the results were compared with available experimental results of the drag coefficient (Cd) and Strouhal (St) number values in the literature. The effect of different groove types and depths on the Cd coefficient has been analyzed and grooves increase the Cd coefficient compared to the smooth cylinder.

Keywords: CFD, drag coefficient, flow over cylinder, passive flow control

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4936 Study of Growth Patterns of the Built-Up Area in Tourism Destinations in Relation to Sustainable Development

Authors: Tagore Sai Priya Nunna, Ankhi Banerjee

Abstract:

The rapid growth of the tourism industry in India in the last few years after the economic crisis in 2009 has been one of the significant causes that led to the Land Use Land Cover change (LULC) of most tourism destinations. The tourist regions are subjected to significant increase in built-up due to increased construction activities for developing accommodation facilities further boosting tourism demand. This research attempts to analyse the changing LULC and the growth pattern of the built-up area within tourist destinations. Four popular tourist destinations, which promises various types of tourism activity and which are significantly dependent on tourism for economic growth, are selected for the study. The study uses remotely sensed data for analysis of land use change through supervised segmentation into five broad classes. Further, the landuse map is reclassified into binary classes to extract the built-up area. The growth patterns of the built-up are analysed in terms of size, shape, direction and form of growth, through a set of spatial metrics. Additionally, a detailed analysis of the existing development pattern corresponding to planned development zones was performed to identify unplanned growth spots in the study regions. The findings of the study provide insights into how tourism has contributed to significant changes in LULC around tourist sites. Also, the study highlights the growth pattern of built-up areas with respect to the type of tourism activity and geographical characteristics. The research attempts to address the need of integrating spatial metrics for the development of sustainable tourism plans as part of the goals of sustainable development.

Keywords: built-up, growth, patterns, tourism, sustainable

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4935 Gas-Liquid Two Phase Flow Phenomenon in Near Horizontal Upward and Downward Inclined Pipe Orientations

Authors: Afshin J. Ghajar, Swanand M. Bhagwat

Abstract:

The main purpose of this work is to experimentally investigate the effect of pipe orientation on two phase flow phenomenon. Flow pattern, void fraction and two phase pressure drop is measured in a polycarbonate pipe with an inside diameter of 12.7mm for inclination angles ranging from -20° to +20° using air-water fluid combination. The experimental data covers all flow patterns and the entire range of void fraction typically observed in two phase flow. The effect of pipe orientation on void fraction and two phase pressure drop is justified with reference to the change in flow structure and two phase flow behavior. In addition to this, the top performing void fraction and two phase pressure drop correlations available in the literature are presented and their performance is assessed against the experimental data in the present study and that available in the literature.

Keywords: flow patterns, inclined two phase flow, pressure drop, void fraction

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4934 Environmental Science: A Proposal for Constructing New Knowledge for Ecotourism Itineraries

Authors: Veruska C. Dutra, Mary L. G. S. Senna

Abstract:

The principle of sustainability has been studied by different sciences with the purpose of formulating clear and concrete models. Much has been discussed about sustainability, and several points of view have been used to try to explain it; environmental science emerges from various environmental discourses that are willing to establish a new concept for understanding this complexity. This way, we focus on the activity of ecotourism as a way to integrate sustainable practices proposed by environmental science, and thus, make it possible to create a new perspective for eco-tourists and the managers of tourist destinations towards nature. The aim of this study was to suggest a direction for environmental awareness, based on environmental science, to change the eco-tourist's view of nature in ecotourism tours. The methodology used was based on a case study concerning the Jalapão State Park - JSP, located in the State of Tocantins, Northern Brazil. The study was based on discussions, theoretical studies, bibliographical research and on-site research. We have identified that to incite the tourists’ awareness, they need to visit nature to understand the environmental problems and promote actions for its preservation. We highlight in this study actions to drive their human perception through environmental science, so that the ecotourism itinerary tours to the JSP, promote a balance between the natural environment and the tourist, making them, in this way, environmental tourists.

Keywords: science, environmental, ecoturism, Jalapão

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4933 Finding the Free Stream Velocity Using Flow Generated Sound

Authors: Saeed Hosseini, Ali Reza Tahavvor

Abstract:

Sound processing is one the subjects that newly attracts a lot of researchers. It is efficient and usually less expensive than other methods. In this paper the flow generated sound is used to estimate the flow speed of free flows. Many sound samples are gathered. After analyzing the data, a parameter named wave power is chosen. For all samples, the wave power is calculated and averaged for each flow speed. A curve is fitted to the averaged data and a correlation between the wave power and flow speed is founded. Test data are used to validate the method and errors for all test data were under 10 percent. The speed of the flow can be estimated by calculating the wave power of the flow generated sound and using the proposed correlation.

Keywords: the flow generated sound, free stream, sound processing, speed, wave power

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4932 Community Based Local Economic Development Strategy Using Strategic Asumption Surfacing and Testing and Expoential Rank Method

Authors: Kholil Kholil, Soecahyadi Soecahyadi

Abstract:

Geographically, Padang Panjang Regency which located in the heart of Western Sumatra has great potentials for the tourism industry. However, these potentials have not been strategically developed for increasing local economic development and people's welfare. The purpose of this research is to design the strategy of sustainable tourism area development using Strategic Assumption Surfacing and Testing (SAST) and Exponential Rank Method (ERM). Result study showed, there are four aspects which importance and certainly for developing tourism area destination in Padang Panjang Regency; (1) tourist information center and promotion, (2) regional cooperation development; (3) minangese center as a center of excellence; and (4) building the center of the public market. To build an attractive tourist area required action plan includes the construction of an information center, center of excellence of minangese, and tourist infrastructure; and public participation is a key success factor for ensuring sustainability of tourism development in Padang Panjang Regency.

Keywords: local economic development, tourism attraction, SAST, ERM

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4931 An Improvement of Flow Forming Process for Pressure Vessels by Four Rollers Machine

Authors: P. Sawitri, S. Cdr. Sittha, T. Kritsana

Abstract:

Flow forming is widely used in many industries, especially in defence technology industries. Pressure vessels requirements are high precision, light weight, seamless and optimum strength. For large pressure vessels, flow forming by 3 rollers machine were used. In case of long range rocket motor case flow forming and welding of pressure vessels have been used for manufacturing. Due to complication of welding process, researchers had developed 4 meters length pressure vessels without weldment by 4 rollers flow forming machine. Design and preparation of preform work pieces are performed. The optimization of flow forming parameter such as feed rate, spindle speed and depth of cut will be discussed. The experimental result shown relation of flow forming parameters to quality of flow formed tube and prototype pressure vessels have been made.

Keywords: flow forming, pressure vessel, four rollers, feed rate, spindle speed, cold work

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4930 Effect of Adverse Pressure Gradient on a Fluctuating Velocity over the Co-Flow Jet Airfoil

Authors: Morteza Mirhosseini, Amir B. Khoshnevis

Abstract:

The boundary layer separation and new active flow control of a NACA 0025 airfoil were studied experimentally. This new flow control is sometimes known as a co-flow jet (cfj) airfoil. This paper presents the fluctuating velocity in a wall jet over the co-flow jet airfoil subjected to an adverse pressure gradient and a curved surface. In these results, the fluctuating velocity at the inner part increasing by increased the angle of attack up to 12o and this has due to the jet energized, while the angle of attack 20o has different. The airfoil cord based Reynolds number has 105.

Keywords: adverse pressure gradient, fluctuating velocity, wall jet, co-flow jet airfoil

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4929 Sentiment Analysis of Tourist Online Reviews Concerning Lisbon Cultural Patrimony, as a Contribute to the City Attractiveness Evaluation

Authors: Joao Ferreira Do Rosario, Maria De Lurdes Calisto, Ana Teresa Machado, Nuno Gustavo, Rui Gonçalves

Abstract:

The tourism sector is increasingly important to the economic performance of countries and a relevant theme to academic research, increasing the importance of understanding how and why tourists evaluate tourism locations. The city of Lisbon is currently a tourist destination of excellence in the European and world-wide panorama, registering a significant growth of the economic weight of its tourist activities in the Gross Added Value of the region. Although there is research on the feedback of those who visit tourist sites and different methodologies for studying tourist sites have been applied, this research seeks to be innovative in the objective of obtaining insights on the competitiveness in terms of attractiveness of the city of Lisbon as a tourist destination, based the feedback of tourists in the Facebook pages of the most visited museums and monuments of Lisbon, an interpretation that is relevant in the development of strategies of tourist attraction. The intangible dimension of the tourism offer, due to its unique condition of simultaneous production and consumption, makes eWOM particularly relevant. The testimony of consumers is thus a decisive factor in the decision-making and buying process in tourism. Online social networks are one of the most used platforms for tourists to evaluate the attractiveness's points of a tourism destination (e.g. cultural and historical heritage), with this user-generated feedback enabling relevant information about the customer-tourists. This information is related to the tourist experience representing the true voice of the customer. Furthermore, this voice perceived by others as genuine, opposite to marketing messages, may have a powerful word-of-mouth influence on other potential tourists. The relevance of online reviews sharing, however, becomes particularly complex, considering social media users’ different profiles or the possible and different sources of information available, as well as their associated reputation associated with each source. In the light of these trends, our research focuses on the tourists’ feedback on Facebook pages of the most visited museums and monuments of Lisbon that contribute to its attractiveness as a tourism destination. Sentiment Analysis is the methodology selected for this research, using public available information in the online context, which was deemed as an appropriate non-participatory observation method. Data will be collected from two museums (Museu dos Coches and Museu de Arte Antiga) and three monuments ((Mosteiro dos Jerónimos, Torre de Belém and Panteão Nacional) Facebook pages during a period of one year. The research results will help in the evaluation of the considered places by the tourists, their contribution to the city attractiveness and present insights helpful for the management decisions regarding this museums and monuments. The results of this study will also contribute to a better knowledge of the tourism sector, namely the identification of attributes in the evaluation and choice of the city of Lisbon as a tourist destination. Further research will evaluate the Lisbon attraction points for tourists in different categories beyond museums and monuments, will also evaluate the tourist feedback from other sources like TripAdvisor and apply the same methodology in other cities and country regions.

Keywords: Lisbon tourism, opinion mining, sentiment analysis, tourism location attractiveness evaluation

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4928 A 2D Numerical Model of Viscous Flow-Cylinder Interaction

Authors: Bang-Fuh Chen, Chih-Chun Chu

Abstract:

The flow induced cylinder vibration or earthquake-induced cylinder motion are moving in an arbitrary direction with time. The phenomenon of flow across cylinder is highly nonlinear and a linear-superposition of flow pattern across separated oscillating direction of cylinder motion is not valid to obtain the flow pattern across a cylinder oscillating in multiple directions. A novel finite difference scheme is developed to simulate the viscous flow across an arbitrary moving circular cylinder and we call this a complete 2D (two-dimensional) flow-cylinder interaction. That is, the cylinder is simultaneously oscillating in x- and y- directions. The time-dependent domain and meshes associated with the moving cylinder are mapped to a fixed computational domain and meshes, which are time independent. The numerical results are validated by several bench mark studies. Several examples are introduced including flow across steam-wise, transverse oscillating cylinder and flow across rotating cylinder and flow across arbitrary moving cylinder. The Morison’s formula can not describe the complex interaction phenomenon between cross flow and oscillating circular cylinder. And the completed 2D computational fluid dynamic analysis should be made to obtain the correct hydrodynamic force acting on the cylinder.

Keywords: 2D cylinder, finite-difference method, flow-cylinder interaction, flow induced vibration

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4927 Deterrents in Tourism Development in Pakistan: A Case Study of Northern Areas

Authors: Qurat Ul Ain Bashir

Abstract:

Since the inception of Pakistan Tourism industry was not on developed level but afterwards 9/11 the tourism has declined rapidly in the country. Despite Northern areas full potential, rich historical and cultural heritage, natural beauty, museums, art galleries, hiking tracks, tourism is not getting that response in Pakistan, which it deserves. In fact Pakistan has been blessed with all the features that could make her a tourist destination. On the other side the attitude of the local people, socio-political condition, lack of facilities of international standards, media’s way of reporting about country, governments’ negligence etc has more adversely affected the international tourism than domestic tourism. From 2013 onward some developments in the said industry has been shown but that is not much encouraging. In 2017 approximately two million tourist visited Pakistan in comparison to 1.75 million in 2016. In the light of above debate the paper attempts to diagnose the causes which are not allowing the reasonable growth of tourism in Pakistan and suggests steps which must be taken to develop the industry through a large scale campaign and long term planning. The methodology about this research is quantitative with reference to description, analysis and recommendations. The material would be collected from the government publications, articles, surveys, tourist accounts, books, internet, magazines.

Keywords: tourism, terrorism, barriers, infrastructure, culture, northern areas

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4926 Liquid-Liquid Plug Flow Characteristics in Microchannel with T-Junction

Authors: Anna Yagodnitsyna, Alexander Kovalev, Artur Bilsky

Abstract:

The efficiency of certain technological processes in two-phase microfluidics such as emulsion production, nanomaterial synthesis, nitration, extraction processes etc. depends on two-phase flow regimes in microchannels. For practical application in chemistry and biochemistry it is very important to predict the expected flow pattern for a large variety of fluids and channel geometries. In the case of immiscible liquids, the plug flow is a typical and optimal regime for chemical reactions and needs to be predicted by empirical data or correlations. In this work flow patterns of immiscible liquid-liquid flow in a rectangular microchannel with T-junction are investigated. Three liquid-liquid flow systems are considered, viz. kerosene – water, paraffin oil – water and castor oil – paraffin oil. Different flow patterns such as parallel flow, slug flow, plug flow, dispersed (droplet) flow, and rivulet flow are observed for different velocity ratios. New flow pattern of the parallel flow with steady wavy interface (serpentine flow) has been found. It is shown that flow pattern maps based on Weber numbers for different liquid-liquid systems do not match well. Weber number multiplied by Ohnesorge number is proposed as a parameter to generalize flow maps. Flow maps based on this parameter are superposed well for all liquid-liquid systems of this work and other experiments. Plug length and velocity are measured for the plug flow regime. When dispersed liquid wets channel walls plug length cannot be predicted by known empirical correlations. By means of particle tracking velocimetry technique instantaneous velocity fields in a plug flow regime were measured. Flow circulation inside plug was calculated using velocity data that can be useful for mass flux prediction in chemical reactions.

Keywords: flow patterns, hydrodynamics, liquid-liquid flow, microchannel

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4925 Power Flow and Modal Analysis of a Power System Including Unified Power Flow Controller

Authors: Djilani Kobibi Youcef Islam, Hadjeri Samir, Djehaf Mohamed Abdeldjalil

Abstract:

The Flexible AC Transmission System (FACTS) technology is a new advanced solution that increases the reliability and provides more flexibility, controllability, and stability of a power system. The Unified Power Flow Controller (UPFC), as the most versatile FACTS device for regulating power flow, is able to control respectively transmission line real power, reactive power, and node voltage. The main purpose of this paper is to analyze the effect of the UPFC on the load flow, the power losses, and the voltage stability using NEPLAN software modules, Newton-Raphson load flow is used for the power flow analysis and the modal analysis is used for the study of the voltage stability. The simulation was carried out on the IEEE 14-bus test system.

Keywords: FACTS, load flow, modal analysis, UPFC, voltage stability

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4924 Investigation of Different Control Stratgies for UPFC Decoupled Model and the Impact of Location on Control Parameters

Authors: S. A. Al-Qallaf, S. A. Al-Mawsawi, A. Haider

Abstract:

In order to evaluate the performance of a unified power flow controller (UPFC), mathematical models for steady state and dynamic analysis are to be developed. The steady state model is mainly concerned with the incorporation of the UPFC in load flow studies. Several load flow models for UPFC have been introduced in literature, and one of the most reliable models is the decoupled UPFC model. In spite of UPFC decoupled load flow model simplicity, it is more robust compared to other UPFC load flow models and it contains unique capabilities. Some shortcoming such as additional set of nonlinear equations are to be solved separately after the load flow solution is obtained. The aim of this study is to investigate the different control strategies that can be realized in the decoupled load flow model (individual control and combined control), and the impact of the location of the UPFC in the network on its control parameters.

Keywords: UPFC, decoupled model, load flow, control parameters

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4923 Investigation of Tourism and Development in Santo Domingo City

Authors: Mary Cruz

Abstract:

Founded from 1496 to 1502, Santo Domingo is the oldest European settlement in the Americas, inhabited without any discontinuity and was the first seat of Spanish power in the new world. Capital of the country since 1932.In this text, we discover Santo Domingo as an international tourist center, Urban Structure, Eco-tourism, Contamination and other issues related to tourism and development of this city. Founded from 1496 to 1502, Santo Domingo is the oldest European settlement in the Americas, inhabited without any discontinuity and was the first seat of Spanish power in the new world. Capital of the country since 1932. Encouraged by the United Nations and the World Bank, many Caribbean governments have encouraged tourism from the 1950s to boost their Third World economies. In this text, we discover Santo Domingo as an international tourist center, Urban Structure, Eco-tourism, Contamination and challenges of the first tourist destination in the Caribbean.

Keywords: eco-tourism, urban structure, contamination, development

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4922 The Islamic Grand Tour: The Case of Caravan Hajj Routes

Authors: Akram Atef Rawshdeh

Abstract:

This research aims to prove the role of Islamic pilgrimage caravans in formulating the concept of the tourism industry and the concept of Grand Tours before that which was found in Europe in the medieval and modern Ages, through its duration and the number of tourists who participated in it and its role in providing tourism services from the establishment of castles and inns that were built To accommodate pilgrims during their travels from different regions of the Islamic world to the holy places in Saudi Arabia, as well as food and beverage services, transportation and support services like tourist security and tourist guide services. This research will depend on the historical method

Keywords: grand tour, hajj caravan routes, tourism services, transportation

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4921 Application of Co-Flow Jet Concept to Aircraft Lift Increase

Authors: Sai Likitha Siddanathi

Abstract:

Present project is aimed at increasing the amount of lift produced by typical airfoil. This is achieved by its modification into the co-flow jet structure where a new internal flow is created inside the airfoil from well-designed apertures on its surface. The limit where produced excess lift overcomes the weight of pumping system inserted in airfoil upper portion, and drag force is converted into thrust is discussed in terms of airfoil velocity and angle of attack. Two normal and co-flow jet models are numerically designed and experimental results for both fabricated normal airfoil and CFJ model have been tested in low subsonic wind tunnel. Application has been made to subsonic NACA 652-415 airfoil. Produced lift in CFJ airfoil indicates a maximum value up to a factor of 5 above normal airfoil nearby flow separation ie in relatively weak flow distribution.

Keywords: flow Jet, lift coefficient, drag coefficient, airfoil performance

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4920 A Numerical Study on the Flow in a Pipe with Perforated Plates

Authors: Myeong Hee Jeong, Man Young Kim

Abstract:

The use of perforated plate and tubes is common in applications such as vehicle exhaust silencers, attenuators in air moving ducts and duct linings in jet engines. Also, perforated plate flow conditioners designed to improve flow distribution upstream of an orifice plate flow meter typically have 50–60% free area but these generally employ a non-uniform distribution of holes of several sizes to encourage the formation of a fully developed pipe flow velocity distribution. In this study, therefore, numerical investigations on the flow characteristics with the various perforated plates have been performed and then compared to the case without a perforated plate. Three different models are adopted such as a flat perforated plate, a convex perforated plate in the direction of the inlet, and a convex perforated plate in the direction of the outlet. Simulation results show that the pressure drop with and without perforated plates are similar each other. However, it can be found that that the different shaped perforated plates influence the velocity contour, flow uniformity index, and location of the fully developed fluid flow. These results can be used as a practical guide to the best design of pipe with the perforated plate.

Keywords: perforated plate, flow uniformity, pipe turbulent flow, CFD (Computational Fluid Dynamics)

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4919 Comparison on Electrode and Ground Arrangements Effect on Heat Transfer under Electric Force in a Channel and a Cavity Flow

Authors: Suwimon Saneewong Na Ayuttaya, Chainarong Chaktranond, Phadungsak Rattanadecho

Abstract:

This study numerically investigates the effects of Electrohydrodynamic on flow patterns and heat transfer enhancement within a cavity which is on the lower wall of channel. In this simulation, effects of using ground wire and ground plate on the flow patterns are compared. Moreover, the positions of electrode wire respecting with ground are tested in the range of angles θ = 0 - 180°. High electrical voltage exposes to air is 20 kV. Bulk mean velocity and temperature of inlet air are controlled at 0.1 m/s and 60°C, respectively. The result shows when electric field is applied, swirling flow is appeared in the channel. In addition, swirling flow patterns in the main flow of using ground plate are widely spreader than that of using ground wire. Moreover, direction of swirling flow also affects the flow pattern and heat transfer in a cavity. These cause the using ground wire to give the maximum temperature and heat transfer higher than using ground plate. Furthermore, when the angle is at θ = 60°, high shear flow effect is obtained. This results show high strength of swirling flow and effective heat transfer enhancement.

Keywords: swirling flow, heat transfer, electrohydrodynamic, numerical analysis

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4918 Field Saturation Flow Measurement Using Dynamic Passenger Car Unit under Mixed Traffic Condition

Authors: Ramesh Chandra Majhi

Abstract:

Saturation flow is a very important input variable for the design of signalized intersections. Saturation flow measurement is well established for homogeneous traffic. However, saturation flow measurement and modeling is a challenging task in heterogeneous characterized by multiple vehicle types and non-lane based movement. Present study focuses on proposing a field procedure for Saturation flow measurement and the effect of typical mixed traffic behavior at the signal as far as non-lane based traffic movement is concerned. Data collected during peak and off-peak hour from five intersections with varying approach width is used for validating the saturation flow model. The insights from the study can be used for modeling saturation flow and delay at signalized intersection in heterogeneous traffic conditions.

Keywords: optimization, passenger car unit, saturation flow, signalized intersection

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4917 Toward a Characteristic Optimal Power Flow Model for Temporal Constraints

Authors: Zongjie Wang, Zhizhong Guo

Abstract:

While the regular optimal power flow model focuses on a single time scan, the optimization of power systems is typically intended for a time duration with respect to a desired objective function. In this paper, a temporal optimal power flow model for a time period is proposed. To reduce the computation burden needed for calculating temporal optimal power flow, a characteristic optimal power flow model is proposed, which employs different characteristic load patterns to represent the objective function and security constraints. A numerical method based on the interior point method is also proposed for solving the characteristic optimal power flow model. Both the temporal optimal power flow model and characteristic optimal power flow model can improve the systems’ desired objective function for the entire time period. Numerical studies are conducted on the IEEE 14 and 118-bus test systems to demonstrate the effectiveness of the proposed characteristic optimal power flow model.

Keywords: optimal power flow, time period, security, economy

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4916 Extrudate Swell under the Effect of Radial Flow and Intrinsic Factors to the Polymer Upstream of the Die

Authors: Hela Krir, Abdelhak Ayadi, Chedly Bradaii

Abstract:

The influence of both intrinsic factors, elastic energy and memory effect, and radial flow on the appearance and the evolution of the extrudate swelling are investigated in the present work. The experiments have been performed with linear polydimethylsiloxane (PDMS) via a capillary rheometer in which a convergent radial flow was created upstream the contraction. The correspondence between the effects of radial flow, entry elastic stored energy and memory effect is discussed. In particular, as the influence of the considered radial flow, extrudate photographs showed that when the gap ratio is reduced, the extrudate swell is lessened than what it is when radial flow geometry is not installed. Moreover, with a narrower gap, the polymer stores less energy during its passage through the die which implies a lower extrudate swelling at the outlet of the die. Results previously mentioned may be related both to shear and elongational components of radial flow.

Keywords: elastic energy, extrudate swell, memory effect, radial flow

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4915 CFD Simulation of Surge Wave Generated by Flow-Like Landslides

Authors: Liu-Chao Qiu

Abstract:

The damage caused by surge waves generated in water bodies by flow-like landslides can be very high in terms of human lives and economic losses. The complicated phenomena occurred in this highly unsteady process are difficult to model because three interacting phases: air, water and sediment are involved. The problem therefore is challenging since the effects of non-Newtonian fluid describing the rheology of the flow-like landslides, multi-phase flow and free surface have to be included in the simulation. In this work, the commercial computational fluid dynamics (CFD) package FLUENT is used to model the surge waves due to flow-like landslides. The comparison between the numerical results and experimental data reported in the literature confirms the accuracy of the method.

Keywords: flow-like landslide, surge wave, VOF, non-Newtonian fluids, multi-phase flows, free surface flow

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4914 Experimental Investigations of a Modified Taylor-Couette Flow

Authors: Ahmed Esmael, Ali El Shrif

Abstract:

In this study the instability problem of a modified Taylor-Couette flow between two vertical coaxial cylinders of radius R1, R2 is considered. The modification is based on the wavy shape of the inner cylinder surface, where inner cylinders with different surface amplitude and wavelength are used. The study aims to discover the effect of the inner surface geometry on the instability phenomenon that undergoes Taylor-Couette flow. The study reveals that the transition processes depends strongly on the amplitude and wavelength of the inner cylinder surface and resulting in flow instabilities that are strongly different from that encountered in the case of the classical Taylor-Couette flow.

Keywords: hydrodynamic instability, Modified Taylor-Couette Flow, turbulence, Taylor vortices

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