An experimental and computational study was made of a single circular jet impinging onto a flat ground board. A 1/2" nozzle running at a fixed nozzle pressure ratio of 1.05 was used in the experimental phase (giving an nozzle exit Reynolds number of 90xlO'), the nozzle to ground plane separation being varied between 2 and 10 nozzle diameters. Measurements were performed in the free and wall jets using single and cross-wire hot-wire anemometry techniques and pitot pressure probes in order to detemine mean velocity and normal and shear stress distributions. Some analysis is also presentedo f earlier measurementso n high pressurer atio impinging jets. Nozzle height was found to effect the initial thickness of the wall jet leaving the impingement region, increasing nozzle to ground plane separation increasing the wall jet thickness, although this separation distance did not seem to affect the rate at which the wall jet grew. Nozzle height was also found to have a large effect on the peak level of turbulence found in the wall jet up to a radial distan ce from the jet axial centre line of 4.5 nozzle diameters, after which the profiles become self-similar. Lowering the nozzle tended to increase the peak level measured in all the turbulent stresses within this development region. The production of turbulent kinetic energy in the wall jet, which is an indication of the amount of work done against the mean flow by the turbulent flow was found to increase dramatically with decreasing nozzle height. This was attributed to greater shearing of the flow at lower nozzle heights due to a thinner wall jet leaving the impingement region. A moving impingement surface was found to cause separation of the wall jet inner boundary layer on the 'approach' side leading to very rapid decay of peak velocity. The point of separation was found to occur at radial positions in the region of 7.0 to 8.0 nozzle diameters, this reducing slightly for lower nozzle heights. A parametric investigation was performed using the k-e turbulence model and the PHOENICS CFD code. It was found that due to inadequacies in the model, it failed to predict accurately the growth of the wall jet, both in terms of its initial thickness and the rate of growth. It did, however, predict an increase in wall jet thickness with both increasing nozzle height and exit turbulence intensity and decreasing nozzle pressure ratio. Modifications were made to the constants in the model to try and improve the predictions,w ith a limited degreeo f successT. he low Reynoldsn umber k-F-t urbulence model was shown to give a slightly improved non-dimensional wall jet profile, although this did not improve the predicted rate of growth of the wall jet.

abstract: Traveling is one of the most enriching and fulfilling activities for most people. Yet factors such as crowded airports, long waiting queues, and inaccessible features of airports and airplanes often make traveling stressful for many individuals including those with disabilities. This qualitative phenomenological research study examined the underexplored area of traveling with a vision disability. Framed around a Co-cultural theoretical perspective, the study examined the lived experiences of vision impaired individuals with regard to receiving disability assistance services during air travel. The study specifically explored the communication strategies that vision impaired individuals employed to manage their assistance-related air travel needs. The study used in-depth interviews for data collection, and a combination of thematic analysis techniques for data analysis. Findings indicated four categories of assistance-related issues that vision impaired participants frequently experienced in their travel: personnel training issues, system issues, policy issues, and physical accessibility issues. The study also identified four Co-cultural communication orientations that participants used in navigating air travel: assertive accommodation, aggressive accommodation, assertive assimilation, and nonassertive assimilation. In addition, the study identified a new Co-cultural communication practice - normalizing for self. Findings of this research conclude that despite three decades since the passage of United States legislation to protect the rights of disabled people, vision impaired travelers still frequently experience inequitable air travel practices. The study offers recommendations on pressing issues concerning policies and regulations that can inform airline executives and federal legislators in facilitating a more equitable and pleasurable air travel experience for those with vision disabilities. / Dissertation/Thesis / Doctoral Dissertation Communication 2020

Business travel has become a considerable part of the daily lives of scarce human resources. Adding to the frustration is the requirement to travel with the current available modes of transport in developing countries, which effectively create a constraint in the ability of scarce human resources to apply their limited time more effectively.This study seeked to understand how and why business travel impacts the productivity of scarce human capital as well as how alternative methods of travel can contribute to increased productivity. In the study the researcher aimed to determine if an on-demand air travel service could be viable in a dynamic market such as South Africa and if so, what value a successful implementation will add to a company and the country.The research was conducted by making use of a descriptive quantitative study over two populations namely business travellers and aircraft pilots. This allowed the researcher to answer the three research questions that were identified.The study has found that not only productivity, but also the work-life balance of scarce human capital is affected negatively by the requirement to conduct business travel. It was also found that on-demand air travel could soon be a viable alternative mode of transport in dynamic markets, which would contribute to improved productivity levels of scarce human capital. This in turn will stimulate company growth and ultimately increase the overall economic growth of the country. / Dissertation (MBA)--University of Pretoria, 2012. / Gordon Institute of Business Science (GIBS) / unrestricted

Background: New technologies have turned out to be an inseparable part of the air travel industry over the last couple of decades, and it brought us many benefits. Nonetheless, these new airport technologies also brought new problems that foster air travellers’ irritation. A negative experience has a relatively worse influence on an airport than a positive; therefore, this is an interesting topic to investigate. There is so far only limited research done about the connection between new customer-facing technologies and customer satisfaction. Due to this lack of analysis, this study has the goal to examine the understanding of the effects of new airport technologies on individual’s satisfaction. Purpose: The purpose of this study is to discover how new customer-facing technologies on airports affect the customers’ satisfaction Method: The research goal is accomplished by implementing qualitative research and collecting the data through ten semi-structured in-depth interviews with various individuals that had a recent air-travel experience which was no earlier than three months. The data analysis is done by performing an inductive research approach. Conclusion: The results show that customer satisfaction process begins at the need recognition and how it is perceived depends on the experience of each person. The way the need is perceived decides the priority of the factors that describe the new customer-facing technologies’ (CFT) service, as a result of that setting the expectations towards the process of interacting with the new CFTs. The customer then interacts with the service while assessing the performance compared to the expectations, and subsequently, a positive or negative disconfirmation is made upon deciding if service is better or worse than expected. A positive disconfirmation results in a satisfied customer and a negative disconfirmation results in a dissatisfied customer.

In this essay I have estimated what impact the Swedish air passenger tax that was introduced in Sweden on April 1st in 2018 has had on passenger numbers in Sweden. The tax was introduced to lower demand for air travel within the public and thus, decrease the aviation industry´s greenhouse gas emissions as aviation contributes through these emissions to a large extent to climate change and is expected to have an even greater impact in the future as the number of air travels are expected to grow continuously. Besides that the emissions from aviation have this large negative impact on the climate, a large part of these emissions are not included in any pricing system or market. Therefore, aviation is a source of negative externalities and the Swedish air passenger tax is an instrument implemented to correct for these negative externalities. Previous studies that have evaluated similar taxes and their effects have reached different conclusions. I have used the difference-in-difference method to estimate any effect from the introduced aviation tax in Sweden. Denmark is used as the control group to compare the development in Sweden with. I found that the tax has had a decreasing effect on passenger numbers in Sweden. It is discussed however if this estimated decrease in passenger numbers might be biased and thus overstated. It is also discussed if this decrease might be due to other reasons than the air passenger tax itself.

Allergic and hypersensitivity reactions such as anaphylaxis and asthma exacerbations may occur during air travel. Although the exact incidence of in-flight asthma and allergic emergencies is not known, we have concerns that this subject has not received the attention it warrants. There is a need to provide passengers at risk and airlines with the necessary measures to prevent and manage these emergencies. A review of the epidemiology, management and approaches to prevention of allergic and asthma emergencies during air travel is presented with the goal of increasing awareness about these important, potentially preventable medical events.

The purpose of this thesis is to achieve an in-depth understanding of how the Vietnamese people in Poland are involved in mobility within air travel (aero-mobility) for their transnational endeavors. This qualitative study is based on 4 semi-structured face-to-face interviews, 3 text-based interviews with the Vietnamese people living in Poland (VP), and on content analysis of texts and images. Air travel can, surprisingly, play a significant role in migration and ethnic studies. The analysis of this thesis relies on the theoretical frameworks of mobility turn, and transnationalism, focusing on the experiences, customs, and habits of the Vietnamese of Poland engaged in air travel. The analysis also includes how air travel can strengthen the diasporic and transnational links of the Vietnamese of Poland, contributing to ethnic weddings, charity events, and religious activities, securing their cultural identity in Poland. The findings indicate that travel customs and habits, social networks, diasporic activities, movements of goods, and exchange of cultures and ideas can be generated by a combination of mobility, transnationalism, and air travel of the Vietnamese people in Poland.

This dissertation is a collection of several models to understand airline and passenger dynamics in the National Airspace System (NAS). Agent-based modeling is one of the most widely used modeling simulation-analysis approaches to understanding the dynamic behavior of complex systems. The usefulness of agent-based modeling has been demonstrated by simulating the complex interactions between airlines, travelers, and airports of a small-scale transportation system. Three airlines, one low cost and two network airlines are simulated to examine how each airline behaves over time to maximize their profit margins for a given passenger demand and operation cost structure. Passenger mode choice and itinerary choice sub modules are embedded in the framework to characterize traveler agent's response to the evolved airline schedule. An airport delay model was implemented to estimate the average delay at each airport. The estimated delay fed into the mode choice and itinerary choice models to update the travel time related variables. International passenger demand is a very important component of the air transportation system in the United States. The proportion of international enplanements relative to total enplanements increased from 8% in 1990 to 11% in 2008. Nine linear regression models are developed to forecast the enplanements from the United States to each of nine international regions. The international enplanements from the CONUS to each world region are modeled as a function of GDP and GDP per capita of both the United States and the specific region. A dummy variable is also used to account for the effects of September 11, 2001. The total number of international enplanements is forecast to increase from 74.7 million in 2008 to 184.4 million in 2028. The average annual growth rate is expected to be 4.7%. The European Union – United States Open Skies Agreement, which became effective March 30, 2008. Mathematical models are developed to forecast the effect of EU-US Open Skies Agreement on commercial airline passenger traffic over the North Atlantic Ocean. Nine econometric models were developed to forecast passenger traffic between the United States and nine selected European countries between 2008 through 2020. 68 new nonstop flights between the United States airports and the European airports are predicted by the model in 2020 using the airport pair passenger demand forecast. London, Heathrow is demonstrated as an example for rerouting the excess air travel passengers from one airport to other airports when the airport operational capacity is exceeded. The proportion of international enplanements relative to total enplanements within CONUS increased from 8% in 1990 to 11% in 2008. 51% of the sampled international and U.S. territories passengers served by U.S. carriers had at least one domestic coupon in 2007. The number of DOI passengers through airport-pairs in each of the historical years (1990-2007) is estimated based on the adjusted 100% international itineraries including pure international itineraries plus the non-CONUS itineraries. The total number of DOI enplanements is estimated to grow from 37.3 million in 1990 to 79.4 million in 2007. 193 CONUS airports are estimated to have at least 10,000 DOI enplanements in 2007. The number of DOI enplanements is forecast to grow from 79.4 million in 2007 to 206.2 million in 2030 with average growth rate of 4.2% per year. In recent years, there has been an increasing use of secondary airports both in Europe and the U.S. Regional airports have long been considered as a possible source of relief to reduce airport congestion at the hub airport and to efficiently accommodate future air travel demand. The conditions under which the secondary airports develop in a metropolitan area are examined. Fifteen multi-airport systems including 19 Operational Evolution Plan airports and 25 active secondary airports are identified in the National Airspace System. Diverse trends of traffic distribution among airports in the same metropolitan area are observed. We observed that the number of markets served at the secondary airports is less than that at the primary airport in the same metropolitan area. Most of the secondary airports are currently dominated by the low-cost carriers. The share of seats supplied by the low-cost carriers at the secondary airports has increased during the period 1990-2008. Full service carriers concentrate their service mainly on the primary airport in all the multi-airport systems analyzed. The average seat capacity per aircraft at the secondary airports is higher than that of primary airports in most of the multi-airport systems. The secondary airports mainly serve the domestic O&D passengers. / Ph. D.

Study project (MEcon) -- University of Stellenbosch, 2000. / ENGLISH ABSTRACT: This assignment explains the search for a mechanism that can increase tourism flow by improved utilisation of airline capacity. The inherent characteristics of air transport indicate that the industry is subject to low short term marginal costs and that it is very tempting to award discount tariffs for last minute bookings. The challenge to management is to attract new passengers with discount tariffs without loosing full tariff passengers. Travel clubs are one of the mechanisms that are utilised to achieve aforementioned objective. These clubs offer mainly discount tariffs on hotel accommodation, car hire and airline tickets to their members. The acceptability of a travel club that applies restricting measures such as for example short notice periods, adaptable depart and return dates and shortened lead times have been tested in the South African market. The majority of respondents surveyed were in favour of such a travel club. An important finding is that South Africans are prepared to travel in a chosen month but that the travel dates within that month are adaptable in exchange for discount tariffs. The research also indicate that the availability of funds was decisive in the decision to travel or not to travel over seas. In order to overcome this problem the introduction of a providence account is recommended as part of the travel club's products. The challenge for the travel club is thus to consolidate the demand and to match it with the excess airline capacity. / AFRIKAANSE OPSOMMING: Hierdie werkstuk beskryf die soeke na 'n meganisme wat toerismevloei kan verhoog deur die verbeterde kapasiteitsbenutting van lugvervoer. Die inherente kenmerke van lugvervoer toon dat die bedryf onderhewig is aan lae korttermyn marginale koste en dat die versoeking groot is om afslagtariewe vir op die nippertjie besprekings toe te staan. Die uitdaging vir die bestuur is om nuwe passasiers met afslagtariewe te lok sonder om voltariefpassasiers prys te gee. Reisklubs is een van die meganismes wat gebruik word om die voorgenoemde doelwit te bereik. Hierdie klubs bied hoofsaaklik afslagtariewe op hotelverblyf, motorhuur en vliegtuigkaartjies aan hul lede. Die aanvaarbaarheid van 'n reisklub wat beperkende rnaatreels soos, byvoorbeeld, kort kennisgewingstydperke, aanpasbare vertrek en terugkeer datums en verkorte leityd toepas, is in die Suid-Afrikaanse mark getoets. Die meerderheid van respondente in die ondersoek was ten gunste van so 'n reisklub. 'n 8elangrike bevinding is dat Suid-Afrikaners bereid is om in 'n gekose maand te reis, maar dat die spesifieke reisdatums in daardie maand aanpasbaar is in ruil vir afslagtariewe. Die navorsing toon ook dat die beskikbaarheid van fondse deurslaggewend is in die besluit om oorsee te reis of nie. Om hierdie probleem te oorkom word die instelling van 'n voorsieningsrekening aanbeveel as dee I van die reisklub se produkte. Die uitdaging aan die reisklub is dus om die vraag te konsolideer en dan af te stem op die oormaatkapasiteit van die lugrederye.

Increased efficiency at airports is necessary to reduce delays and fuel consumption. Many of the busiest airports in the nation have at least one pair of closely spaced parallel runways (CSPRs), defined by a separation of less than 2500 ft, with one runway dedicated to arrivals and the other to departures. CSPRs experience a large decrease in capacity under instrument conditions because they can no longer operate independently. In order to mitigate this decrease in capacity and to increase efficiency, proposed herein is a departure regulator for runways so configured, along with a plan of study to investigate the effects of this regulator. The proposed departure regulator makes use of data from precision tracking systems such as ADS-B to issue automated or semi-automated departure clearances. Assuming sequential departure separations are sufficient for clearance, the regulator will automatically issue, or advise the controller to issue, the departure clearance as soon as the arrival on the adjacent runway has descended below its decision height. By issuing the departure clearance earlier, the departure regulator reduces the gap between a pair of arrivals that is required to clear a departure. By decreasing the gap, the regulator increases the number of opportunities where a departure clearance can be issued, given a particular arrival stream. A simulation models the effects of the regulator and quantifies the resulting increases in capacity. The simulation results indicate that all forms of the regulator would provide significant gains of between 14% and 23% in capacity over the current operating paradigm. The results also indicate that the capacity gains are greatest at high arrival rates. Therefore, implementation of the departure regulator could significantly decrease the congestion at many major airports during inclement weather.