Kooperativer Bibliotheksverbund

UID:

Format: 1 online resource (ix, 128 pages)

Content: The gas transfer process across the air-water interface in a ottom-shear-induced turbulent environment was investigated to gain improved fundamental understanding of the physical mechanisms that control the process. For this purpose, it is necessary to reveal the hydrodynamics of the flow field as well as the molecular diffusion and the turbulent transport contributions to the total flux. Therefore, detailed laboratory experiments were conducted to obtain these information.The experiments were performed in a grid-stirred tank using a combined Particle Image Velocimetry - Laser Induced Fluorescence (PIV-LIF) technique that has been developed for these near surface gas transfer measurements. The turbulence characteristics of the velocity near the interface were acquired from the PIV measurements and showed generally good agreement with the theoretical profiles from Hunt & Graham (1978). The LIF technique enabled visualization of the planar concentration fields which provided more insight into the gas transfer mechanisms. The high data resolution allowed detailed quantification of the concentration distribution within the thin aqueous boundary layer. The mean and turbulent fluctuation characteristics of the concentration could be elucidated and the molecular diffusion contribution to the total flux across the interface could be determined. With the combined PIV-LIF technique, which enables simultaneous and spatially synoptic measurements of 2D velocity and concentration fields, the turbulent mass flux term cw and also the total mass flux across the air-water interface could be quantified directly. For the first time, a particular trend can be inferred from the measured mean cw profiles. It could also be shown that the contribution of the turbulent mass flux to the total gas flux is significant. The co-spectra indicated different behavior for the cases with lower and higher turbulent Reynolds numbers.The interrelated interpretation of the obtained results suggest that the gas transfer process is controlled by a spectrum of different eddy sizes and the gas transfer at different turbulence levels can be associated to certain eddy sizes. For high turbulence levels the gas transfer should be asymptotic to the small eddy model, whereas for low turbulence level to the large eddy model. The new results of turbulent mass flux should aid as an excellent database in refining numerical models and developing more accurate models for the prediction of the transfer velocity.

Additional Edition: ISBN 1000003544

Language: English

UID:

Format: 1 online resource (ix, 128 pages)

Content: The gas transfer process across the air-water interface in a ottom-shear-induced turbulent environment was investigated to gain improved fundamental understanding of the physical mechanisms that control the process. For this purpose, it is necessary to reveal the hydrodynamics of the flow field as well as the molecular diffusion and the turbulent transport contributions to the total flux. Therefore, detailed laboratory experiments were conducted to obtain these information.The experiments were performed in a grid-stirred tank using a combined Particle Image Velocimetry - Laser Induced Fluorescence (PIV-LIF) technique that has been developed for these near surface gas transfer measurements. The turbulence characteristics of the velocity near the interface were acquired from the PIV measurements and showed generally good agreement with the theoretical profiles from Hunt & Graham (1978). The LIF technique enabled visualization of the planar concentration fields which provided more insight into the gas transfer mechanisms. The high data resolution allowed detailed quantification of the concentration distribution within the thin aqueous boundary layer. The mean and turbulent fluctuation characteristics of the concentration could be elucidated and the molecular diffusion contribution to the total flux across the interface could be determined. With the combined PIV-LIF technique, which enables simultaneous and spatially synoptic measurements of 2D velocity and concentration fields, the turbulent mass flux term cw and also the total mass flux across the air-water interface could be quantified directly. For the first time, a particular trend can be inferred from the measured mean cw profiles. It could also be shown that the contribution of the turbulent mass flux to the total gas flux is significant. The co-spectra indicated different behavior for the cases with lower and higher turbulent Reynolds numbers.The interrelated interpretation of the obtained results suggest that the gas transfer process is controlled by a spectrum of different eddy sizes and the gas transfer at different turbulence levels can be associated to certain eddy sizes. For high turbulence levels the gas transfer should be asymptotic to the small eddy model, whereas for low turbulence level to the large eddy model. The new results of turbulent mass flux should aid as an excellent database in refining numerical models and developing more accurate models for the prediction of the transfer velocity.

Additional Edition: ISBN 1000003544

Language: English

UID:

Format: 1 online resource (ix, 128 pages)

Content: The gas transfer process across the air-water interface in a ottom-shear-induced turbulent environment was investigated to gain improved fundamental understanding of the physical mechanisms that control the process. For this purpose, it is necessary to reveal the hydrodynamics of the flow field as well as the molecular diffusion and the turbulent transport contributions to the total flux. Therefore, detailed laboratory experiments were conducted to obtain these information.The experiments were performed in a grid-stirred tank using a combined Particle Image Velocimetry - Laser Induced Fluorescence (PIV-LIF) technique that has been developed for these near surface gas transfer measurements. The turbulence characteristics of the velocity near the interface were acquired from the PIV measurements and showed generally good agreement with the theoretical profiles from Hunt & Graham (1978). The LIF technique enabled visualization of the planar concentration fields which provided more insight into the gas transfer mechanisms. The high data resolution allowed detailed quantification of the concentration distribution within the thin aqueous boundary layer. The mean and turbulent fluctuation characteristics of the concentration could be elucidated and the molecular diffusion contribution to the total flux across the interface could be determined. With the combined PIV-LIF technique, which enables simultaneous and spatially synoptic measurements of 2D velocity and concentration fields, the turbulent mass flux term cw and also the total mass flux across the air-water interface could be quantified directly. For the first time, a particular trend can be inferred from the measured mean cw profiles. It could also be shown that the contribution of the turbulent mass flux to the total gas flux is significant. The co-spectra indicated different behavior for the cases with lower and higher turbulent Reynolds numbers.The interrelated interpretation of the obtained results suggest that the gas transfer process is controlled by a spectrum of different eddy sizes and the gas transfer at different turbulence levels can be associated to certain eddy sizes. For high turbulence levels the gas transfer should be asymptotic to the small eddy model, whereas for low turbulence level to the large eddy model. The new results of turbulent mass flux should aid as an excellent database in refining numerical models and developing more accurate models for the prediction of the transfer velocity.

Additional Edition: ISBN 1000003544

Language: English

UID:

Format: 1 online resource (898 pages)

Content: Das Lehrbuch Aerothermodynamik, das die klassischen Gebiete der Hyperschallaerodynamik mit der Chemie heißer Gase verknüpft, ergänzt den Lehrstoff der Strömungsmechanik-Lehrbuchreihe. Es ist als Vertiefung der strömungsmechanischen Grundlagen für die interessierten Maschinenbaustudenten der höheren Semester und Doktoranden der Graduiertenkollegs verfaßt. Das Lehrbuch beabsichtigt nicht, das Gebiet der Aerothermodynamik umfassend zu behandeln. Es umfaßt die Stoffauswahl einer vom Erstautor über mehr als einem Jahrzehnt gehaltenen Spezialvorlesung, die dem Wissensstand eines Maschinenbaustudenten im 8. Semester angepaßt ist, der erfahrungsgemäß noch keine Berührung mit der Nichtgleichgewichts-Thermodynamik und gaskinetischen Betrachtungsweise der Strömungsmechanik hatte. Die Mitautoren haben im Rahmen ihrer Dissertationen den Vorlesungsstoff weiter vertieft und insbesondere in den numerisch orientierten Kapiteln die neuesten Ergebnisse eingearbeitet. Damit wird auch der im Beruf stehende Ingenieur für seine praktische Projektarbeit in den Hyperschall-Technologieprogrammen und Projekten zahlreiche Anregungen finden können.Der Lehrstoff gliedert sich in Einführungskapitel über die Grundlagen und Eigenschaften von Hyperschallströmungen und die Grundbegriffe der Nichtgleichgewichts-Thermodynamik heißer Gase. Es folgen die Kapitel "Verdünnte Strömungen" und "Kontinuumsströmungen", in denen den gaskinetischen und kontinuumsmechanischen Grundgleichungen , ausgewählten numerischen Lösungsmethoden und der Modellierung der Luftchemie ein besonders breiter Raum eingeräumt wurde. Das Lehrbuch schließt mit dem Kapitel über einige ausgewählte Hyperschall-Projekte und Technologieprogramme unter Einbeziehung der Versuchsanlagen und Großrechner-Verbundsysteme ab.

Additional Edition: ISBN 1000003549

Language: German

UID:

Format: 1 online resource (167 pages)

Content: This textbook on fluid mechanics is aimed at engineering students at Bachelor's degree level. In Chapter 2 the fundamentals of fluid mechanics, needed for the description and analysis of flows in technology, are presented. One-dimensional stream filament theory, along with the momentum integral and angular momentum integral equations, already present us with one method of constructing fluid technological appliances and experiments. For example, the dimensions of a machine can be determined quite accurately in one first step and predictions made about the flow losses which occur.However, these methods fail when machines are to be optimized, or when appliances are to be developed to operate under extreme conditions, such as silent operation, high efficiency, small dimensions, greatly damped oscillatory behavior, etc. In addition to this, even for most simple cases of application, simple fluid mechanical fundamentals cannot determine the operating behavior of a machine accurately enough. This requires extensive experiments to be carried out and these can be very costly and time consuming.At this point we refer to more detailed textbooks which progress systematically from the fundamental fluid mechanical equations and their methods of solution to the application of fluid mechanical software.The methods used in fluid mechanics are analytical, numerical and experimental. Although numerical methods are increasingly used to replace experimental methods, all three are still needed to solve fluid mechanical problems. This book is restricted to theoretical, that is analytical, methods. After working through this book, students are qualified to understand the basics and phenomena of fluid mechanics, and will have obtained an initial insight into fluid mechanical software, even if further studies into the fundamental equations of fluid mechanics and numerical methods are necessary for the application of this software.The composition of this book is partly very theoretical. In order not to lose sight of the connection to technical applications during the extensive derivations, we have selected flows past airplane wings, flows past vehicles and flows in pipes of process engineering systems as representative examples to illustrate the basics of one-dimensional fluid mechanics.We now introduce the student to the great variety of fluid mechanical applications, demonstrating that flows are all around us in our technological environment, by describing selected examples of flows in the following introductory sections.

Additional Edition: ISBN 1000003548

Language: English

UID:

Format: 1 online resource

Additional Edition: ISBN 1000003545

Language: English

UID:

Format: 1 online resource (167 pages)

Content: This textbook on fluid mechanics is aimed at engineering students at Bachelor's degree level. In Chapter 2 the fundamentals of fluid mechanics, needed for the description and analysis of flows in technology, are presented. One-dimensional stream filament theory, along with the momentum integral and angular momentum integral equations, already present us with one method of constructing fluid technological appliances and experiments. For example, the dimensions of a machine can be determined quite accurately in one first step and predictions made about the flow losses which occur.However, these methods fail when machines are to be optimized, or when appliances are to be developed to operate under extreme conditions, such as silent operation, high efficiency, small dimensions, greatly damped oscillatory behavior, etc. In addition to this, even for most simple cases of application, simple fluid mechanical fundamentals cannot determine the operating behavior of a machine accurately enough. This requires extensive experiments to be carried out and these can be very costly and time consuming.At this point we refer to more detailed textbooks which progress systematically from the fundamental fluid mechanical equations and their methods of solution to the application of fluid mechanical software.The methods used in fluid mechanics are analytical, numerical and experimental. Although numerical methods are increasingly used to replace experimental methods, all three are still needed to solve fluid mechanical problems. This book is restricted to theoretical, that is analytical, methods. After working through this book, students are qualified to understand the basics and phenomena of fluid mechanics, and will have obtained an initial insight into fluid mechanical software, even if further studies into the fundamental equations of fluid mechanics and numerical methods are necessary for the application of this software.The composition of this book is partly very theoretical. In order not to lose sight of the connection to technical applications during the extensive derivations, we have selected flows past airplane wings, flows past vehicles and flows in pipes of process engineering systems as representative examples to illustrate the basics of one-dimensional fluid mechanics.We now introduce the student to the great variety of fluid mechanical applications, demonstrating that flows are all around us in our technological environment, by describing selected examples of flows in the following introductory sections.

Additional Edition: ISBN 1000003548

Language: English

UID:

Format: 1 online resource (167 pages)

Content: This textbook on fluid mechanics is aimed at engineering students at Bachelor's degree level. In Chapter 2 the fundamentals of fluid mechanics, needed for the description and analysis of flows in technology, are presented. One-dimensional stream filament theory, along with the momentum integral and angular momentum integral equations, already present us with one method of constructing fluid technological appliances and experiments. For example, the dimensions of a machine can be determined quite accurately in one first step and predictions made about the flow losses which occur.However, these methods fail when machines are to be optimized, or when appliances are to be developed to operate under extreme conditions, such as silent operation, high efficiency, small dimensions, greatly damped oscillatory behavior, etc. In addition to this, even for most simple cases of application, simple fluid mechanical fundamentals cannot determine the operating behavior of a machine accurately enough. This requires extensive experiments to be carried out and these can be very costly and time consuming.At this point we refer to more detailed textbooks which progress systematically from the fundamental fluid mechanical equations and their methods of solution to the application of fluid mechanical software.The methods used in fluid mechanics are analytical, numerical and experimental. Although numerical methods are increasingly used to replace experimental methods, all three are still needed to solve fluid mechanical problems. This book is restricted to theoretical, that is analytical, methods. After working through this book, students are qualified to understand the basics and phenomena of fluid mechanics, and will have obtained an initial insight into fluid mechanical software, even if further studies into the fundamental equations of fluid mechanics and numerical methods are necessary for the application of this software.The composition of this book is partly very theoretical. In order not to lose sight of the connection to technical applications during the extensive derivations, we have selected flows past airplane wings, flows past vehicles and flows in pipes of process engineering systems as representative examples to illustrate the basics of one-dimensional fluid mechanics.We now introduce the student to the great variety of fluid mechanical applications, demonstrating that flows are all around us in our technological environment, by describing selected examples of flows in the following introductory sections.

Additional Edition: ISBN 1000003548

Language: English

UID:

Format: 1 online resource (898 pages)

Content: Das Lehrbuch Aerothermodynamik, das die klassischen Gebiete der Hyperschallaerodynamik mit der Chemie heißer Gase verknüpft, ergänzt den Lehrstoff der Strömungsmechanik-Lehrbuchreihe. Es ist als Vertiefung der strömungsmechanischen Grundlagen für die interessierten Maschinenbaustudenten der höheren Semester und Doktoranden der Graduiertenkollegs verfaßt. Das Lehrbuch beabsichtigt nicht, das Gebiet der Aerothermodynamik umfassend zu behandeln. Es umfaßt die Stoffauswahl einer vom Erstautor über mehr als einem Jahrzehnt gehaltenen Spezialvorlesung, die dem Wissensstand eines Maschinenbaustudenten im 8. Semester angepaßt ist, der erfahrungsgemäß noch keine Berührung mit der Nichtgleichgewichts-Thermodynamik und gaskinetischen Betrachtungsweise der Strömungsmechanik hatte. Die Mitautoren haben im Rahmen ihrer Dissertationen den Vorlesungsstoff weiter vertieft und insbesondere in den numerisch orientierten Kapiteln die neuesten Ergebnisse eingearbeitet. Damit wird auch der im Beruf stehende Ingenieur für seine praktische Projektarbeit in den Hyperschall-Technologieprogrammen und Projekten zahlreiche Anregungen finden können.Der Lehrstoff gliedert sich in Einführungskapitel über die Grundlagen und Eigenschaften von Hyperschallströmungen und die Grundbegriffe der Nichtgleichgewichts-Thermodynamik heißer Gase. Es folgen die Kapitel "Verdünnte Strömungen" und "Kontinuumsströmungen", in denen den gaskinetischen und kontinuumsmechanischen Grundgleichungen , ausgewählten numerischen Lösungsmethoden und der Modellierung der Luftchemie ein besonders breiter Raum eingeräumt wurde. Das Lehrbuch schließt mit dem Kapitel über einige ausgewählte Hyperschall-Projekte und Technologieprogramme unter Einbeziehung der Versuchsanlagen und Großrechner-Verbundsysteme ab.

Additional Edition: ISBN 1000003549

Language: German

UID:

Format: 1 online resource

Additional Edition: ISBN 1000003545

Language: English