Joachim Peinke - Böcker

This volume collects the edited and reviewed contributions presented in the 8th iTi Conference on Turbulence, held in Bertinoro, Italy, in September 2018. In keeping with the spirit of the conference, the book was produced afterwards, so that the authors had the opportunity to incorporate comments and discussions raised during the event.    The respective contributions, which address both fundamental and applied aspects of turbulence, have been structured according to the following main topics:  I TheoryII Wall-bounded flowsIII Simulations and modellingIV ExperimentsV Miscellaneous topicsVI Wind energy

This volume collects the edited and reviewed contributions presented in the 8th iTi Conference on Turbulence, held in Bertinoro, Italy, in September 2018.

This volume collects the edited and reviewed contribution presented in the 9th iTi Conference that took place virtually, covering fundamental and applied aspects in turbulence.

This volume collects the edited and reviewed contribution presented in the 9th iTi Conference that took place virtually, covering fundamental and applied aspects in turbulence.

This book collects the edited and reviewed contribution presented in the 10th iTi conference in Bertinoro, covering fundamental and applied aspects in turbulence.

This book collects the edited and reviewed contribution presented in the 10th iTi conference in Bertinoro, covering fundamental and applied aspects in turbulence. In the spirit of the iTi conference, the book is produced after the conference so that the authors had the opportunity to incorporate comments and discussions raised during the meeting. The iTi has become an established biannual conference on turbulence research with 80 to 100 participants and places value on creating an environment to stimulate discussions and personal contacts in the beautiful town of Bertinoro in Northern Italy close to Bologna, continuing a tradition that has started in Bad Zwischenahn/Germany with the first edition of the conference in 2003. The content-related focus areas of the conference are the interdisciplinary aspects of turbulence, defining the abbreviation iTi—interdisciplinary turbulence initiative. iTi attracts scientist from the engineering, physics, and mathematics communities.

This book presents recent advances in the physical, conceptual, and methodological foundations required for the reliable design, analysis, and operation of offshore megastructures. Modern offshore wind turbines are expected to make a significant contribution to the success of the energy transition. Future turbines are considerably larger than those in operation today, reaching total heights of more than 300 meters and featuring rotors with diameters exceeding 280 meters. At these scales, turbines are exposed to little-known influences and environmental conditions that develop at altitudes above 100 meters. Due to their dimensions and the delicate construction required, environmental effects and the interactions between individual components are becoming increasingly important. Established methods for the design and operation of wind turbines are no longer applicable to structures of this size. Therefore, new concepts are being developed worldwide to create an integrated design and operation methodology based on the concept of digital twins. This approach goes far beyond the sequential, state-of-the-art design process and calls for research into new physical, conceptual, and methodological foundations: The term offshore megastructures is often used to describe slender offshore wind turbines with rated powers exceeding 20 MW. These megastructures not only possess enormous dimensions and masses but also interact highly dynamically with their environment. According to this definition, the newest turbines developed by industry are already approaching the scale of megastructures. On one hand, this emphasizes that offshore megastructures become indispensable for future power generation. On the other hand, there is still no operational experience spanning 25 years or more for turbines of this scale. Hence, without entirely new design and operation methodologies, reliable long-term operation cannot be ensured. Integrating insights from various related fields, it highlights the paradigm shift essential for realizing the future of sustainable offshore wind energy.

This volume collects the edited and reviewed contributions presented in the 5th iTi Conference in Bertinoro covering fundamental aspects in turbulent flows. In the spirit of the iTi initiative, the volume is produced after the conference so that the authors had the possibility to incorporate comments and discussions raised during the meeting.Turbulence presents a large number of aspects and problems, which are still unsolved and which challenge research communities in engineering and physical sciences both in basic and applied research. The book presents recent advances in theory related to new statistical approaches, effect of non-linearities and presence of symmetries. This edition presents new contributions related to the physics and control of laminar-turbulent transition in wall-bounded flows, which may have a significant impact on drag reduction applications. Turbulent boundary layers, at increasing Reynolds number, are the main subject of both computational and experimental long research programs aimed at improving our knowledge on scaling, energy distribution at different scales, structure eduction, roughness effects to name only a few. Like previous editions several numerical and experimental analysis of complex flows, mostly related to applications, are presented.The structure of the present book is as such that contributions have been bundled according to covering topics i.e. I Theory, II Stability, III Wall bounded flows, IV, Complex flows, V Acoustic, VI Numerical methods.The volume is dedicated to the memory of Prof. Rudolf Friedrich who prematurely died in Münster/Germany on the 16th of August 2012. In his honor the conference has started with a special session dedicated to his work.

This volume collects the edited and reviewed contributions presented in the 5th iTi Conference in Bertinoro covering fundamental aspects in turbulent flows.

This volume collects the edited and reviewedcontributions presented in the 6th iTi Conference in Bertinoro, coveringfundamental and applied aspects in turbulence. In the spirit of the iTiconference, the volume has been produced after the conference so that theauthors had the possibility to incorporate comments and discussions raisedduring the meeting.In the present book the contributions have been structuredaccording to the topics :I TheoryII Wall bounded flowsIII Particles in flowsIV Free flows           V Complex flowsThe volume is dedicated to the memory of Prof. KonradBajer who prematurely passed away in Warsaw on August 29, 2014.

This book presents the view of European wind energy experts on the long-term research challenges to be solved in order to develop wind energy beyond the applications of today and tomorrow. By this book, the European Academy of Wind Energy (eawe), representing universities and institutes with a significant windenergy programme in 14 countries, wants to:identify current technological and scientific barriers and to stimulate new creative ideas to overcome these barriersdefine priorities for future scientific researchrethink our scientific view of wind energystimulate the cooperation among researchers in fundamental and applied sciences towards wind energy researchThe eawe has discussed these long-term research with an explicit focus on a longer-term perspective, in contrast toresearch agendas addressing short- to medium-term research activities. In other words, this long-term research agenda is driven by problems and curiosity, addressing basic research and fundamental knowledge in 11 research areas, ranging from physics and design to environmental and societal aspects. Because of the very nature of this initiative, thisdocument does not intend to be permanent or complete. It shows the vision of the experts of the European Academy of Wind Energy, but other viewsmay be possible. The eawe sincerely hopes that it will spur an even more intensive discussion worldwide within thewind energy community.

This volume collects the edited and reviewed contribution presented in the 7th iTi Conference in Bertinoro, covering fundamental and applied aspects in turbulence. In the spirit of the iTi conference, the volume is produced after the conference so that the authors had the opportunity to incorporate comments and discussions raised during the meeting.In the present book, the contributions have been structured according to the topics:I TheoryII Wall bounded flowsIII Pipe flowIV ModellingV ExperimentsVII Miscellaneous topics

This volume collects the edited and reviewedcontributions presented in the 6th iTi Conference in Bertinoro, coveringfundamental and applied aspects in turbulence. In the spirit of the iTiconference, the volume has been produced after the conference so that theauthors had the possibility to incorporate comments and discussions raisedduring the meeting.In the present book the contributions have been structuredaccording to the topics :I TheoryII Wall bounded flowsIII Particles in flowsIV Free flows           V Complex flowsThe volume is dedicated to the memory of Prof. KonradBajer who prematurely passed away in Warsaw on August 29, 2014.

This book presents the view of European wind energy experts on the long-term research challenges to be solved in order to develop wind energy beyond the applications of today and tomorrow. By this book, the European Academy of Wind Energy (eawe), representing universities and institutes with a significant windenergy programme in 14 countries, wants to:identify current technological and scientific barriers and to stimulate new creative ideas to overcome these barriersdefine priorities for future scientific researchrethink our scientific view of wind energystimulate the cooperation among researchers in fundamental and applied sciences towards wind energy researchThe eawe has discussed these long-term research with an explicit focus on a longer-term perspective, in contrast toresearch agendas addressing short- to medium-term research activities. In other words, this long-term research agenda is driven by problems and curiosity, addressing basic research and fundamental knowledge in 11 research areas, ranging from physics and design to environmental and societal aspects. Because of the very nature of this initiative, thisdocument does not intend to be permanent or complete. It shows the vision of the experts of the European Academy of Wind Energy, but other viewsmay be possible. The eawe sincerely hopes that it will spur an even more intensive discussion worldwide within thewind energy community.

This volume collects the edited and reviewed contribution presented in the 7th iTi Conference in Bertinoro, covering fundamental and applied aspects in turbulence.

Besides turbulence, there is hardly any other scientific topic which has been considered a prominent scientific challenge for such a long time. The special interest in turbulence is not only based on it being a difficult scientific problem but also on its meaning in the technical world and our daily life. This carefully edited book comprises recent basic research as well as research related to the applications of turbulence. Therefore, both leading engineers and physicists working in the field of turbulence were invited to the iTi Conference on Turbulence held in Bad Zwischenahn, Gemany 21st - 24th of September 2003. Topics discussed include, for example, scaling laws and intermittency, thermal convection, boundary layers at large Reynolds numbers, isotropic turbulence, stochastic processes, passive and active scalars, coherent structures, numerical simulations, and related subjects.

Besides turbulence there is hardly any other scientific topic which has been considered as a prominent scientific challenge for such a long time. The special interest in turbulence is not only based on it being a difficult scientific problem but also on its meaning in the technical world and our daily life. This carefully edited book comprises recent basic research as well as research related to the applications of turbulence. Therefore, both leading engineers and physicists working in the field of turbulence were invited to the iTi Conference on Turbulence held in Bad Zwischenahn, Gemany 25th - 28th of September 2005. Discussed topics include, for example, scaling laws and intermittency, thermal convection, boundary layers at large Reynolds numbers, isotropic turbulence, stochastic processes, passive and active scalars, coherent structures, numerical simulations, and related subjects.

This book is comprised of the proceedings of the Euromech Colloquium 464b 'Wind Energy'. It comprises reports on basic research, as well as research related to the practical exploitation and application of wind energy. The book describes the atmospheric turbulent wind condition on different time scales, and the interaction of wind turbines with both wind and water flows. These influence the design, operation and maintenance of offshore wind turbines.

Our life is a highly nonlinear process. It starts with birth and ends with death; in between there are a lot of ups and downs. Quite often, we believe that stable and steady situations, probably easy to capture by linearization, are paradisiacal, but already after a short period of everyday routine we usually become bored and seek change, that is, nonlinearities. If we reflect for a while, we notice that our life and our perceptions are mainly determined by nonlinear phenomena, for example, events occurring suddenly and unexpectedly. One may be surprised by how long scientists tried to explain our world by models based on a linear ansatz. Due to the lack of typical nonlinear patterns, although everybody experienced nonlinearities, nobody could classify them and, thus,· study them further. The discoveries of the last few decades have finally provided access to the world of nonlinear phenomena and have initiated a unique inter­ disciplinary field of research: nonlinear science. In contrast to the general tendency of science to become more branched out and specialized as the result of any progress, nonlinear science has brought together many different disciplines. This has been motivated not only by the immense importance of nonlinearities for science, but also by the wonderful simplicity ohhe concepts. Models like the logistic map can be easily understood by high school students and have brought revolutionary new insights into our scientific under­ standing.

This third issue on “progress in turbulence” is based on the third ITI conference (ITI interdisciplinary turbulence initiative), which took place in Bertinoro, North Italy. Researchers from the engineering and physical sciences gathered to present latest results on the rather notorious difficult and essentially unsolved problem of turbulence. This challenge is driving us in doing basic as well as applied research. Clear progress can be seen from these contributions in different aspects. New - phisticated methods achieve more and more insights into the underlying compl- ity of turbulence. The increasing power of computational methods allows studying flows in more details. Increasing demands of high precision large turbulence - periments become aware. In further applications turbulence seem to play a central issue. As such a new field this time the impact of turbulence on the wind energy conversion process has been chosen. Beside all progress our ability to numerically calculate high Reynolds number turbulent flows from Navier-Stokes equations at high precision, say the drag co- ficient of an airfoil below one percent, is rather limited, not to speak of our lack of knowledge to compute this analytically from first principles. This is rather - markable since the fundamental equations of fluid flow, the Navier-Stokes eq- tions, have been known for more than 150 years.

Besides turbulence, there is hardly any other scientific topic which has been considered a prominent scientific challenge for such a long time. The special interest in turbulence is not only based on it being a difficult scientific problem but also on its meaning in the technical world and our daily life. This carefully edited book comprises recent basic research as well as research related to the applications of turbulence. Therefore, both leading engineers and physicists working in the field of turbulence were invited to the iTi Conference on Turbulence held in Bad Zwischenahn, Gemany 21st - 24th of September 2003. Topics discussed include, for example, scaling laws and intermittency, thermal convection, boundary layers at large Reynolds numbers, isotropic turbulence, stochastic processes, passive and active scalars, coherent structures, numerical simulations, and related subjects.

Besides turbulence there is hardly any other scientific topic which has been considered as a prominent scientific challenge for such a long time. The special interest in turbulence is not only based on it being a difficult scientific problem but also on its meaning in the technical world and our daily life. This carefully edited book comprises recent basic research as well as research related to the applications of turbulence. Therefore, both leading engineers and physicists working in the field of turbulence were invited to the iTi Conference on Turbulence held in Bad Zwischenahn, Gemany 25th - 28th of September 2005. Discussed topics include, for example, scaling laws and intermittency, thermal convection, boundary layers at large Reynolds numbers, isotropic turbulence, stochastic processes, passive and active scalars, coherent structures, numerical simulations, and related subjects.

This book is comprised of the proceedings of the Euromech Colloquium 464b "Wind Energy". It comprises reports on basic research, as well as research related to the practical exploitation and application of wind energy. The book describes the atmospheric turbulent wind condition on different time scales, and the interaction of wind turbines with both wind and water flows. These influence the design, operation and maintenance of offshore wind turbines.

This third issue on “progress in turbulence” is based on the third ITI conference (ITI interdisciplinary turbulence initiative), which took place in Bertinoro, North Italy. Researchers from the engineering and physical sciences gathered to present latest results on the rather notorious difficult and essentially unsolved problem of turbulence. This challenge is driving us in doing basic as well as applied research. Clear progress can be seen from these contributions in different aspects. New - phisticated methods achieve more and more insights into the underlying compl- ity of turbulence. The increasing power of computational methods allows studying flows in more details. Increasing demands of high precision large turbulence - periments become aware. In further applications turbulence seem to play a central issue. As such a new field this time the impact of turbulence on the wind energy conversion process has been chosen. Beside all progress our ability to numerically calculate high Reynolds number turbulent flows from Navier-Stokes equations at high precision, say the drag co- ficient of an airfoil below one percent, is rather limited, not to speak of our lack of knowledge to compute this analytically from first principles. This is rather - markable since the fundamental equations of fluid flow, the Navier-Stokes eq- tions, have been known for more than 150 years.

This fourth issue on "progress in turbulence" is based on the fourth ITI conference (ITI interdisciplinary turbulence initiative), which took place in Bertinoro, North Italy. Leading researchers from the engineering and physical sciences presented latest results in turbulence research. Basic as well as applied research is driven by the rather notorious difficult and essentially unsolved problem of turbulence. In this collection of contributions clear progress can be seen in different aspects, ranging from new quality of numerical simulations to new concepts of experimental investigations and new theoretical developments. The importance of turbulence is shown for a wide range of applications including: combustion, energy, flow control, urban flows, are few examples found in this volume. A motivation was to bring fundamentals of turbulence in connection with renewable energy. This lead us to add a special topic relevant to the impact of turbulence on the wind energy conversion. The structure of the present book is as such that contributions have been bundled according to covering topics i.e. I Basic Turbulence Aspects, II Particle Laden Flows, III Modeling and Simulations, IV, Experimental Methods, V Special Flows, VI Atmospheric Boundary Layer, VII Boundary Layer, VIII Wind Energy and IX Convection. This book is dedicated to the memory of Prof. Tim Nickels.  Shortly after giving an invited lecture at the 4th ITI conference, the turbulence community lost a world-class scientist, a friend and devoted family man.

This fourth issue on "progress in turbulence" is based on the fourth ITI conference (ITI interdisciplinary turbulence initiative), which took place in Bertinoro, North Italy. Leading researchers from the engineering and physical sciences presented latest results in turbulence research. Basic as well as applied research is driven by the rather notorious difficult and essentially unsolved problem of turbulence. In this collection of contributions clear progress can be seen in different aspects, ranging from new quality of numerical simulations to new concepts of experimental investigations and new theoretical developments. The importance of turbulence is shown for a wide range of applications including: combustion, energy, flow control, urban flows, are few examples found in this volume. A motivation was to bring fundamentals of turbulence in connection with renewable energy. This lead us to add a special topic relevant to the impact of turbulence on the wind energy conversion. The structure of the present book is as such that contributions have been bundled according to covering topics i.e. I Basic Turbulence Aspects, II Particle Laden Flows, III Modeling and Simulations, IV, Experimental Methods, V Special Flows, VI Atmospheric Boundary Layer, VII Boundary Layer, VIII Wind Energy and IX Convection. This book is dedicated to the memory of Prof. Tim Nickels.  Shortly after giving an invited lecture at the 4th ITI conference, the turbulence community lost a world-class scientist, a friend and devoted family man.

This book presents the results of the seminar “Wind Energy and the Impact of Turbulence on the Conversion Process” which was supported from three societies, namely the EUROMech, EAWE and ERCOFATC and took place in Oldenburg, Germany in spring 2012.The seminar was one of the first scientific meetings devoted to the common topic of wind energy and basic turbulence. The established community of researchers working on the challenging puzzle of turbulence for decades met the quite young community of researchers, who face the upcoming challenges in the fast growing field of wind energy applications.From the fluid mechanical point of view, wind turbines are large machines operating in the fully turbulent atmospheric boundary layer. In particular they are facing small-scale turbulent inflow conditions. It is one of the central puzzles in basic turbulence research to achieve a fundamental understanding of the peculiarities of small-scale turbulence. This book helps to better understand the resulting aerodynamics around the wind turbine’s blades and the forces transmitted into the machinery in this context of puzzling inflow conditions. This is a big challenge due to the multi-scale properties of the incoming wind field ranging from local flow conditions on the profile up to the interaction of wake flows in wind farms.