A physical explanation for the saturation of broadband shock-associated noise (BBSAN) intensity with increasing jet stagnation temperature has eluded investigators. An explanation is proposed for this phenomenon with the use of an acoustic analogy. For this purpose the acoustic analogy of Morris and Miller is examined. To isolate the relevant physics, the scaling of BBSAN at the peak intensity level at the sideline ( = 90 degrees) observer location is examined. Scaling terms are isolated from the acoustic analogy and the result is compared using a convergent nozzle with the experiments of Bridges and Brown and using a convergent-divergent nozzle with the experiments of Kuo, McLaughlin, and Morris at four nozzle pressure ratios in increments of total temperature ratios from one to four. The equivalent source within the framework of the acoustic analogy for BBSAN is based on local field quantities at shock wave shear layer interactions. The equivalent source combined with accurate calculations of the propagation of sound through the jet shear layer, using an adjoint vector Green s function solver of the linearized Euler equations, allows for predictions that retain the scaling with respect to stagnation pressure and allows for the accurate saturation of BBSAN with increasing stagnation temperature. This is a minor change to the source model relative to the previously developed models. The full development of the scaling term is shown. The sources and vector Green s function solver are informed by steady Reynolds-Averaged Navier-Stokes solutions. These solutions are examined as a function of stagnation temperature at the first shock wave shear layer interaction. It is discovered that saturation of BBSAN with increasing jet stagnation temperature occurs due to a balance between the amplification of the sound propagation through the shear layer and the source term scaling.A physical explanation for the saturation of broadband shock-associated noise (BBSAN) intensity with increasing jet stagnation temperature has eluded investigators. An explanation is proposed for this phenomenon with the use of an acoustic analogy. For this purpose the acoustic analogy of Morris and Miller is examined. To isolate the relevant physics, the scaling of BBSAN at the peak intensity level at the sideline psi = 90 degrees) observer location is examined. Scaling terms are isolated from the acoustic analogy and the result is compared using a convergent nozzle with the experiments of Bridges and Brown and using a convergent-divergent nozzle with the experiments of Kuo, McLaughlin, and Morris at four nozzle pressure ratios in increments of total temperature ratios from one to four. The equivalent source within the framework of the acoustic analogy for BBSAN is based on local field quantities at shock wave shear layer interactions. The equivalent source combined with accurate calculations of the propagation of sound through the jet shear layer, using an adjoint vector Green s function solver of the linearized Euler equations, allows for predictions that retain the scaling with respect to stagnation pressure and allows for the accurate saturation of BBSAN with increasing stagnation temperature. This is a minor change to the source model relative to the previously developed models. The full development of the scaling term is shown. The sources and vector Green s function solver are informed by steady Reynolds-Averaged Navier-Stokes solutions. These solutions are examined as a function of stagnation temperature at the first shock wave shear layer interaction. It is discovered that saturation of BBSAN with increasing jet stagnation temperature occurs due to a balance between the amplification of the sound propagation through the shear layer and the source term scaling.

https://ntrs.nasa.gov/api/citations/20120009953/downloads/20120009953.pdf

Aircraft noise and the airport community

The Scaling of Broadband Shock-Associated Noise with Increasing Temperature

............................................................................... ii DEDICATION........................................................................... iii ACKNOWLEDGEMENTS ..................................................... iv LIST OF PAPERS PUBLSHED IN ASSOCIATION WITH THIS THESIS............................................................................. v CHAPTER 1 – BACKGROUND OF RESEARCH ............... 1 1.0. INTRODUCTION .............................................................. 1 1.1. ROLES OF TRANSPORTATION IN THE SOCIETY . 1 1.1.1. Economic Role of Transportation ................................................................................ 1 1.1.2. Social Role of Transportation ........................................................................................ 2 1.1.3. Political Role of Transportation .................................................................................... 3 1.1.4. Environmental Role of Transportation ....................................................................... 3 1.1.4.1. Safety ............................................................................................................................ 3 1.1.4.2. Air Pollution ............................................................................................................... 4 1.1.4.3. Noise Pollution .......................................................................................................... 4 1.1.4.4. Energy Consumption ............................................................................................... 5 1.1.4.5. Land Use and Aesthetics ........................................................................................ 5 1.2. THE NIGERIAN ROAD NETWORK DEVELOPMENTS .................................................................... 7 1.2.1. EFFECT OF THE POOR STATE OF ROAD TRANSPORT INFRASTRUCTURE AND SERVICES ON ENTERPRENEURSHIP IN NIGERIA ........................................................................................................................................ 8 1.2.2. THE STATE OF ROAD TRANSPORT INFRASTRUCTURE AND ITS EFFECT ON THE NIGERIAN ECONOMY .................................................................... 10 1.3. RESEARCH QUESTIONS .............................................. 12 1.4. RESEARCH AIM AND OBJECTIVES ......................... 13 1.5. THESIS STRUCTURE .................................................... 14 CHAPTER 2 – LITERATURE REVIEW ............................ 16 2.0. INTRODUCTION ............................................................ 16 2.1. ROAD TRANSPORT ....................................................... 16 2.1.1. SAFETY ASPECT OF ROAD TRANSPORT ..................................................... 17 2.1.1.1. FACTORS CONTRIBUTING TO ROAD TRAFFIC CRASHES IN NIGERIA ................................................................................................................................. 18 2.1.1.1.1. Driver factor ................................................................................................... 18 2.1.1.1.2. Vehicle factor ................................................................................................. 18 2.1.1.1.3. Roadway factor .............................................................................................. 19 2.1.1.1.4. Environmental factor .................................................................................... 20 2.1.1.1.5. The Impact Of Road Traffic Crashes On The Nigerian Economy .. 20 2.1.2. SECURITY ASPECT OF ROAD TRANSPORT ................................................ 21 2.1.3. EMMISSIONS FROM ROAD TRANSPORT ..................................................... 21 2.1.4. ENERGY CONSUMPTION ...................................................................................... 23 2.1.5. NOISE POLLUTION ................................................................................................... 23 Joyce .O. Onatere-Ubrurhe (1015205) PhD in Built Environment, Faculty of Science and Engineering, University of Wolverhampton. Developing a Benchmarking methodology for the Nigerian Transport Sector. vii 2.1.6. INVESTMENT ON INFRASTRUCTURE ........................................................... 24 2.1.7. INTERMODALITY ...................................................................................................... 26 2.1.8. ROAD TRANSPORT OPERATION IN NIGERIA ........................................... 26 2.1.8.1. THE ROAD TRANPORT OPERATORS DURING THE COLONIAL PERIOD ................................................................................................................................... 26 2.1.8.2. THE NIGERIAN MOTOR TRANSPORT OPERATORS SINCE THE TIME OF INDEPENCE ...................................................................................................... 38 2.1.8.3. NATIONAL UNION OF ROAD TRANSPORT WORKERS ................ 40 2.2. RAIL TRANSPORT ......................................................... 45 2.2.1. TREND OF THE NIGERIAN RAIL TRANSPORT (1970 – 2015) .............. 46 2.2.2. NOTABLE CHALLENGES FACING THE NIGERIAN RAIL SECTOR . 47 2.2.3. NIGERIAN RAIL MODERNISATION PROGRAMME ................................. 48 2.3. AIR TRANSPORT ........................................................... 50 2.3.1. SAFETY ASPECT OF AIR TRANSPORT ........................................................... 50 2.3.2. CAUSES OF AIR CRASHES IN NIGERIA ......................................................... 51 2.3.2.1. Ageing/faulty Aircraft: ......................................................................................... 51 2.3.2.2. Pilot error ................................................................................................................. 51 2.3.2.3. Environmental factor ............................................................................................ 51 2.3.3. SECURITY ASPECT .............................................................................................. 51 2.3.4. EMISSIONS ............................................................................................................... 51 2.3.5. ENERGY CONSUMPTION ................................................................................. 52 2.3.6. NOISE POLLUTION .............................................................................................. 52 2.4. MARITIME TRANSPORT ............................................. 52 2.4.1. HISTORY OF THE NIGERIAN MARITIME INDUSTRY ............................ 53 2.4.2. DEVELOPMENT AND IMPORTANCE OF MARITIME TRANSPORT TO THE NIGERIAN ECONOMY .............................................................................................. 57 2.4.2.1. Transportation ......................................................................................................... 57 2.4.2.2. Facilitation of Trade and Commerce................................................................ 58 2.4.2.3. Revenue generation and availability of finance ............................................ 59 2.4.2.4. Promotion of Tourism .......................................................................................... 60 2.4.2.5. Development of related economic activities .................................................. 61 2.4.2.6. Creation of Employment and job opportunities ............................................ 62 2.4.2.7. Enhancement of industrial growth and development .................................. 63 2.4.2.8. Institutional development .................................................................................... 64 2.4.2.9. International relations and peaceful co-existence......................................... 65 2.4.2.10. Socio-political harmony .................................................................................... 65 2.4.2.11. Defense and Security – territorial protection .............................................. 66 2.4.3. PROBLEMS OF THE NIGERIAN PORT SYSTEM ......................................... 66 2.4.3.1. Malfunctioning port system ................................................................................ 68 2.4.3.2. Government’s Intervention and interferences ............................................... 70 2.4.3.3. Inadequate infrastructural facilities for efficient and fast services .......... 72 2.4.3.4. Complicated Tariff Structure and Implementation ...................................... 73 2.4.3.5. Misunderstanding of the usage and current function of ports ................... 74 2.4.3.6. Proliferation of government agencies operating at the ports..................... 75 2.4.3.7. Cumbersome documentation and delivery procedure ................................. 75 2.4.3.8. Insecurity of cargo and lives ............................................................................... 76 2.4.3.9. Manpower and Labor problems ......................................................................... 76 2.4.3.10. NPA’s Lack of Financial Autonomy ............................................................. 77 Joyce .O. Onatere-Ubrurhe (1015205) PhD in Built Environment, Faculty of Science and Engineering, University of Wolverhampton. Developing a Benchmarking methodology for the Nigerian Transport Sector. viii 2.4.3.11. Port Environmental Pollution Problems ....................................................... 77 2.4.4. SAFETY ASPECT OF MARITIME TRANSPORT ........................................... 78 2.4.4.1. CAUSES OF MARINE ACCIDENTS IN NIGERIA ................................ 79 2.4.5. SECURITY ASPECT OF MARITIME TRANSPORT ..................................... 79 2.4.6. ENERGY CONSUMPTION ...................................................................................... 79 2.4.7. EMMISSIONS ................................................................................................................ 79 2.4.8. NOISE POLLUTION .................................................

background

Developing a benchmarking methodology for the Nigerian transport sector

Airport noise is a recognized by-product of a transportation-based economy. Because the number of airports, aircraft, and flight operations over adjacent airport communities are essential to the economic base, noise monitoring systems are being installed by airport proprietors. Currently, there are 25 systems in operation at airports in North America (two additional airports are in the process of bidding on and installation of noise monitoring systems). They have been installed for a variety of reasons and purposes, including compliance with enacted regulations or standards. These airport noise systems consist of four basic components: remote monitoring station, central processing station, software, and accessories. It is anticipated that the number of such systems will increase more rapidly in the future, partially due to available federal funding under Federal Aviation Regulations (FAR) Part 150: Airport Noise and Land Use Planning.

Airport noise monitoring systems in north america

-The aviation sector is one of the most important sectors for any country especially its ability to: promote interconnectedness within countries as well as between countries. However, the sector faces many risks caused by various emergencies and accidents associated with the sector, and much so in the precincts of airports. The impact of these accidents causes monumental social, economic and environmental consequences to victims. The exponential growth of the sector in the country calls for special attention by relevant stakeholders to devise strategies to address disaster preparedness issues. This is especially due to the fact that the country has already experienced a number of aviation disasters and mishaps related to the industry. Consequently, this study sought to assess the effects of land use changes on airport and flight safety at Wilson Airport. This study was carried out at Wilson airport located in Nairobi West. The qualitative design was applied in this study to analyze and describe the effects of land use changes on airport and flight safety in a rapidly growing aviation sector. A total of 216 respondents were targeted by the study (including 150 members of the community, 30 aviation regulators, 30 air operators and 6 service providers) out of which 195 responded (including 132 members of the community, 28 aviation regulators, 29 air operators and 6 service provider) giving a response rate of 90%. Primary data was collected by use of questionnaires, interview guide and Focused Group Discussions while Secondary data were collected from written or published records and maps from the Kenya National Bureau of statistics. Quantitative data was analysed by use of descriptive statistics such as frequencies and percentages while qualitative data was analysed using content analysis. The study found that 42 (74%) of the respondents indicated that land use changes have effect on flight safety. The land use changes included: setting up of major shopping malls near the airport, proximity of Uhuru gardens to the airport, adjacent Nairobi national park, Mitumba slums, upcoming high-rise development and existence of motor garages next to the airport. The results from correlation analysis showed that disaster preparedness is positively related with land use changes with a Pearson‟s Correlation Coefficient of r = 0.509 and that at a level of significance of 0.000 meaning that it is statistically significant as p value is less than 0.05. It was recommended that the government should do an urgent operation on land encroachment as this is perceived to be a disaster in the waiting.

/pdf/effects-of-land-use-changes-on-airport-and-flight-safety-a-20h638m3ng.pdf

Effects of land use changes on airport and flight safety; a study of Wilson Airport, Kenya

This paper presents improvement of the reception noise suppression method during formation flights of aircraft. Since aircraft communication equipment is very important for flight mission and safety to perform the functions of internal/external communications, it is required to implement noise-free, clean communication quality, and transmitting/receiving functions. Therefore, the FTA (Fault Tree Analysis) analysis and failure search were performed on the reception noise, and the internal noise of the intercom that affected the reception noise and the none-transmition phenomenon was identified. We changed the multiple grounds of the intercom to a single ground and applied an improved method of filtering the DC Offset voltage. As a result, the voice quality of the communication system of the aircraft was improved through the reduction of the reception noise during formation flights, and it was verified by ground and flight tests.

Aircraft noise and the airport community

Citations

The Scaling of Broadband Shock-Associated Noise with Increasing Temperature

Developing a benchmarking methodology for the Nigerian transport sector

Airport noise monitoring systems in north america

Effects of land use changes on airport and flight safety; a study of Wilson Airport, Kenya

Improvement of Reception Noise During Formation Flight of Aircraft

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