Sound generation by a vortex ring collision

A collision between two vortex rings and its sound generation is studied numerically using the contour dynamics method. Results suggest that the radial acceleration and the rate of change of the axial acceleration of the vortex rings are the more important dynamic parameters for sound generation during the interaction. The former is important at or near the pass-through instant when the vortex rings are coplanar and are of unequal strength. The latter, being important in the sound generation during a head-on collision before the vortex ring cores are very close to each other, especially when the rings are thin, is also important in sound generation by an unequal strength vortex ring collision after the pass through when the vortex cores are separated by a distance so that the mutual induction strength does not result in significant change of the impulse of the stronger ring. ©1995 Acoustical Society of America.published_or_final_versio

Effects of a background axisymmetric potential flow on vortex ring pairing sound

Sound generated by the pairing of two coaxial vortex rings in the presence of a background axisymmetric potential flow was studied numerically. Results show that the background flow substantially affects the sound generation process in the beginning of the vortex ring interaction. They also suggest that the axial jerk and radial acceleration/deceleration of vortex rings are the major mechanisms through which pairing sound is produced. The effect of background flow mean shear rate on sound generation is also discussed and the results suggest that higher sound levels will be generated when the vortex rings are interacting within the region of high mean shear in a low speed laminar jet. ©1998 Acoustical Society of America.published_or_final_versio

OBRAS DEL MUSEO [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

Inviscid two dimensional vortex dynamics and a soliton expansion of the sinh-Poisson equation

The dynamics of inviscid, steady, two dimensional flows is examined for the case of a hyperbolic sine functional relation between the vorticity and the stream function. The 2-soliton solution of the sinh-Poisson equation with complex wavenumbers will reproduce the Mallier-Maslowe pattern, a row of counter-rotating vortices. A special 4-soliton solution is derived and the corresponding flow configuration is studied. By choosing special wavenumbers complex flows bounded by two rigid walls can result. A conjecture regarding the number of recirculation regions and the wavenumber of the soliton expansion is offered. The validity of the new solution is verified independently by direct differentiation with a computer algebra software. The circulation and the vorticity of these novel flow patterns are finite and are expressed in terms of well defined integrals. The questions of the linear stability and the nonlinear evolution of a finite amplitude disturbance of these steady vortices are left for future studies. © 1998 American Institute of Physics.published_or_final_versio

Sound sources in the interactions of two inviscid two-dimensional vortex pairs

Author name used in this publication: S. K. Tang2000-2001 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Proceedings of the ASAIHL Seminar on the Role of the ASAIHL in Combating Health Hazards of Environmental Pollution: June 17-20, 1992, University of Hong Kong

Includes bibliographical references.Sponsored by the ASAIHLpublished_or_final_versionLegal controls of environmental pollution in Asia: how effective are they? Allen, J. Allen, J. 256Hong Kong's water pollution controls: are we serious? Baillie, B.G. Baillie, B.G. 265Environmental law in Hong Kong - a legal practitioner's point of view Skrine, R. Skrine, R. 277Has the use of unleaded petrol provided a lead-free environment in Hong Kong? Au, C.T. Au, C.T. Chou, K.M. Chou, K.M. Wong, K.Y. Wong, K.Y. 282The influence of the health act on present environmental problems Prabawa Utama, S.H. Prabawa Utama, S.H. 288Characteristics of acid rain in mainland China Hong, Y.T. Hong, Y.T. 42Environmental impact assessment and the role of legislation in environmental control - the case of Malaysia Idris, A.B. Idris, A.B. Fuad, A. Fuad, A. 294Social responsbility awareness assessment of selected university respondents in combating environmental pollution Barcelona, A.C. Barcelona, A.C. 301Alternatives to legal controls on environmental pollution Kaine, G. Kaine, G. Reeve, I. Reeve, I. Musgrave, W. Musgrave, W. 306Introduction 315Towards low-waste technology Diaper, J. Diaper, J. 317Changing environmental values and institution building: the role of ASAIHL Hills, P. Hills, P. 325The nature and control of motor vehicle emissions - methanol as an alternative fuel Cheung, C.S. Cheung, C.S. Lui, Y.B. Lui, Y.B. Leung, T.P. Leung, T.P. 335Prevention and treatment of environmental pollution Mena, M.M. Mena, M.M. 332Treatment and disposal of heavy metal wastes using cementitious solidification Peralta, G.L. Peralta, G.L. Ballesteros, F.C. Ballesteros, F.C. Cepeda, M.L. Cepeda, M.L. 340A membrane anaerobic system for wastewater treatment Fakrul-Razi, A. Fakrul-Razi, A. 346Prevention and treatment of air pollution in Hong Kong Lam, J.C. Lam, J.C. 351Environmental education - a strategy for the treatment and prevention of environmental pollution Manalo, J.A. Manalo, J.A. Sergovia, V. Sergovia, V. Hocson, T.R. Hocson, T.R. 357Bacterial reduction during sewage treatment - the Hong Kong experience Hodgkiss, I.J. Hodgkiss, I.J. Chiu, S.H.C. Chiu, S.H.C. 360Treatment and prevention of environmental pollution in the Philippines De Jesus, E.M. De Jesus, E.M. 366Microbiological study of shellfish and water quality in Deep Bay, Hong Kong Kueh, C.S.W. Kueh, C.S.W. 369Environmental deterioration in greater Bangkok, Thailand Paraken, Y. Paraken, Y. 376The 'polluter pays' principle: the distribution of economic impacts Rahim, K.A. Rahim, K.A. 378The role of Philippine ASAIHL institutions in combating the hazards of environmental pollution in Manila Quirino, T.U. Quirino, T.U. 35Education programmes for training of agrichemical users in New Zealand Penman, D.R. Penman, D.R. 31The role of institutions of higher learning in combating health hazards of environmental pollution Rampal, K.G. Rampal, K.G. Ismail, N. Ismail, N. 26The contribution of health care departments in tertiary institutions in Hong Kong to combating the hazards of pollution King, A.R. King, A.R. 19Australian approaches to finger printing sources of environmental lead with isotopes Gulson, B.L. Gulson, B.L. 13D Treatment and prevention of environmental pollutionC Legal controls of environmental pollutionB Monitoring and instrumentation of environmental pollutionA Health hazards of environmental pollutionCountry reportsKeynote address Wang, Gungwu Wang, Gungwu 2Impact of industry on the health of surrounding communities: an analysis of epidemiological and public health challenges Bhopal, R.S. Bhopal, R.S. 65Epidemiology and environmental health: reliable risk measurement in well-populations Lam, T.H. Lam, T.H. Hedley, A.J. Hedley, A.J. Peters, J. Peters, J. 74An investigation into the presence of anaerobic bacteria in coastal waters of Hong Kong Boost, M.V. Boost, M.V. Wong, L.P. Wong, L.P. Wong, P.S. Wong, P.S. Ma, K.C. Ma, K.C. 82Pollutions within the built environment Burnett, J. Burnett, J. Chan, D.W.T. Chan, D.W.T. 87The effects of pesticides use on the health of on farmers in East Java, Indonesia Mukono, J. Mukono, J. 94Noise and human activities in Hong Kong: a review Tan, T.C. Tan, T.C. Wong, L.T.L. Wong, L.T.L. 98Analysis of organophosphorus insecticides in vegetables Tanner, P.A. Tanner, P.A. Leung, K.H. Leung, K.H. 105Health risk and environmental pollution: the hidden factors Peters, J. Peters, J. Lui, J. Lui, J. Wong, C.M. Wong, C.M. Hedley, A.J. Hedley, A.J. Lam, T.H. Lam, T.H. Ong, S.G. Ong, S.G. Tam, A.Y.C. Tam, A.Y.C. 109Risk assessment and management in the prevention of adverse effects on human health and the environment Spickett, J.T. Spickett, J.T. 117Indoor and outdoor pollution in shops and offices in Hong Kong and health effects Bacon-Shone, J. Bacon-Shone, J. Liao, S. Liao, S. 122Climatological assessment of potential heat stress in Hong Kong Kyle, W.J. Kyle, W.J. 126Asbestos dust: a silent enemy Lam, K.Y. Lam, K.Y. 131Integrating environmental health problems into urban planning: problems in the Asian-Pacific region and the challenges for universities Simpson, R.W. Simpson, R.W. 134Organic solvent exposure in some manufacturing industries in Malaysia Tan, G.L.E. Tan, G.L.E. 138Introduction 145Introductino 63Monitoring and instrumentation of environmental pollution Tebbutt, T.H.Y. Tebbutt, T.H.Y. 145The air quality monitoring programme of the Hong Kong environmental protection department Leung, R.T.M. Leung, R.T.M. 152Low technology sampling can show spatial and temporal patterns of airborne metal pollution Lloyd, O.L. Lloyd, O.L. Fay, Gailey Fay, Gailey 159Heavy metal contamination in coastal waters - a case study of the north coast of Central Java, Indonesia Supriharyono Supriharyono 165Determination of phosphorus in natural water at parts per trillion level by laser thermal lens effect Wu, L. Wu, L. Siu, G.G. Siu, G.G. Chiu, D.D.S. Chiu, D.D.S. Stokes, M.J. Stokes, M.J. 171A geographical approach to evaluating the human impact upon water quality Peart, M.R. Peart, M.R. 178Modular auto-enrichment subsystem for use in environmental high pressure liquid chromatography analysis Chen, S.C. Chen, S.C. Chang, J.Y. Chang, J.Y. Wang, R.K. Wang, R.K. 183Exposure to environmental pollutants in the work environment: a case study of a traffic toll booth in Malaysia Yaziz, M.I. Yaziz, M.I. 187A proposed air quality index in Hong Kong Ng, C.N. Ng, C.N. Tanner, P.A. Tanner, P.A. 191Background level of trace elements in soils of mainland China Chen, J.S. Chen, J.S. Tao, S. Tao, S. Deng, B.S. Deng, B.S. Wang, X.J. Wang, X.J. 196Indoor monitoring of nitrogen oxides Cheung, M.T. Cheung, M.T. 200The role of Thai universities in combating health hazards of environmental pollution Wangsuphachart, V.L. Wangsuphachart, V.L. 54Development of a piezoelectric crystal sorption detector for continuous monitoring of organic vapours at the workplace Fung, Y.S. Fung, Y.S. 205Effects of some standard fixatives on fish gill morphology Shepherd, M. Shepherd, M. Ivanstoff, W. Ivanstoff, W. 210Improving the total environmental of Singapore Tan, T.C. Tan, T.C. 46Simulation of urban traffic noise on the environment Pamanikabud, P. Pamanikabud, P. 215Investigation into the haze episodes in the Kelang Valley, Malaysia Samah, A.A. Samah, A.A. 221Photoacoustic determination of organic pollutant gases in Hong Kong air Shi, B. Shi, B. Siu, G.G. Siu, G.G. Chiu, D.D.S. Chiu, D.D.S. 228Application of the proton induced X-ray emission (PIXE) technique for the study of respirable suspended particulated (RSP) in Hong Kong Cai, Z.X. Cai, Z.X. Sze, P.Y.K. Sze, P.Y.K. Stokes, M.J. Stokes, M.J. Young, E.C.M. Young, E.C.M. 234Follow-up stream sediment geochemical reconnaissance surveys in the vicinity of Tai Mo Shan, New Territories, Hong Kong Yim, W.W.S. Yim, W.W.S. Ng, C.Y. Ng, C.Y. Thornton, I. Thornton, I. 240Introduction 249Environmental pollution, higher education, and the rule of law Axline, M. Axline, M. 25

Inviscid two dimensional vortex dynamics and a soliton expansion of the sinh-Poisson equation

Author name used in this publication: S. K. TangVersion of RecordPublishe