Turbulence may appear random but we now know that there is much orderand coherent/persistent flow structure embedded in its randomness. Turbulence also consists of eddies of many different sizes with a mix of random and coherent/persistent behaviour at each scale. As a result of this multi-scale structure with its mix of disorder and persistent order, turbulent flows are good mixers. However, they consume a lot of energy to be maintained. Laminar flows require less energy consumotion. The purpose of this research is twofold. Firstly, to create and control new classes of flows which are laminar yet with multi-scale flow structure of eddies within eddies. The potential advantages for the design of new effiicient mixers is enormous. Secondly, to understand how the multi-scale eddying structure and its coherent and random components impact on stirring and mixing. Such an understanding has never been attempted as it is very difficult to ground it on laboratory experiments of turbulent flows where monitoring,let alone controlling, the turbulent eddy structure whilst, at the same time, measuring statistics and properties of the resulting stirring and mixing is virtuallly impossible. Instead, we propose to create fully controllled multi-scale bespoke turbulent-like flows with controlled multi-scale topologies (characterised in terms of hyperbolic and elliptic stagnation points and fractal dimensions) and controlled time-dependencies of the flows. With such multi-scale control in space and time of such bespoke flows, it is then possible to study the relations between the various elements of the turbulent-like flow structure (multi-scale streamline topology, time dependence, imposed randomness and persistence, etc) and the various statistics and properties of the flows (e.g. how much energy at each scale, i.e energy spectra) and of their stirring and mixing proporties (e.g. mixing rates, rate of separation of neighboring fluid elements, etc). At a subsequent stage, such detailed spatio-temporal topological understanding of these fully controlled bespoke laboratory flows will procvide the conceptual tools and framework and the type of knowledge necessary to derive models of turbulent mixing based on the actual persistent topology of the turbulence and its time dependence. Turbulent mixing models to this date effectively assume the turbulence to be no more than just a random mixer, and such models are known to be fundamentally flawed.

The Innovative Manufacturing and Construction Research Centre (IMCRC) will undertake a wide variety of work in the Manufacturing, Construction and product design areas. The work will be contained within 5 programmes:1. Transforming Organisations / Providing individuals, organisations, sectors and regions with the dynamic and innovative capability to thrive in a complex and uncertain future2. High Value Assets / Delivering tools, techniques and designs to maximise the through-life value of high capital cost, long life physical assets3. Healthy & Secure Future / Meeting the growing need for products & environments that promote health, safety and security4. Next Generation Technologies / The future materials, processes, production and information systems to deliver products to the customer5. Customised Products / The design and optimisation techniques to deliver customer specific products.Academics within the Loughborough IMCRC have an internationally leading track record in these areas and a history of strong collaborations to gear IMCRC capabilities with the complementary strengths of external groups.Innovative activities are increasingly distributed across the value chain. The impressive scope of the IMCRC helps us mirror this industrial reality, and enhances knowledge transfer. This advantage of the size and diversity of activities within the IMCRC compared with other smaller UK centres gives the Loughborough IMCRC a leading role in this technology and value chain integration area. Loughborough IMCRC as by far the biggest IMRC (in terms of number of academics, researchers and in funding) can take a more holistic approach and has the skills to generate, identify and integrate expertise from elsewhere as required. Therefore, a large proportion of the Centre funding (approximately 50%) will be allocated to Integration projects or Grand Challenges that cover a spectrum of expertise.The Centre covers a wide range of activities from Concept to Creation.The activities of the Centre will take place in collaboration with the world's best researchers in the UK and abroad. The academics within the Centre will be organised into 3 Research Units so that they can be co-ordinated effectively and can cooperate on Programmes.

The proposed research study aims at investigating rotationally induced flows in cylindrical geometries to bring new insight on the type, nature and occurrence of flow transitions and instabilities as well as to offer novel information to better understand mixing mechanisms in related equipment and therefore develop and improve mixing modelling.Mixing is a physical phenomenon that is often encountered in everyday life. One of the simplest example is that of a spoon stirring a coffee cup to blend milk. Numerous applications can be found in the chemical and biochemical industries that utilise mixing of two or more phases or reactants.From this point of view several reactor designs can be distinguished that attain mixing in different ways: oscillatory flow mixers (OFM), static mixers, stirred vessels and shaking flasks. The last two types of reactors are rotationally induced mixing reactors for which a flow is generated by a stirring impeller or by the movement of the tray holding a cylindrical container along a circumferential orbit. The analogy between these two types of reactors is even more evident when considering that shaking flasks are often small scale mixers employed in the early stage of bioprocess development, before the developed process is implemented in a large scale industrial stirred tank.However, while the fluid mechanics of stirred tank reactors have been extensively studied, little is known about the flow patterns, flow transitions and instabilities taking place in shaken flasks. The consequences of this lack of knowledge are twofold: (a) a process developed in the shaken flasks cannot be fully characterised, undermining its reproducibility; (b) its operating conditions cannot be properly correlated to those present in industrial, scaled up reactors, usually stirred tanks, for which a vast amount of data is available in literature.Taking into account the differences in the flow geometry, certain types of instability and unsteadiness that are documented in the few papers dealing with fluid mechanics in shaken flasks, recall those that are encountered in a cylindrical container with a rotating endwall for which data is available in literature. The similarity between the two systems (i.e. shaking flask of cylindrical shape, and cylindrical container) is also indicated by the fact that the movement of the shaken flask can be seen as the superimposition of the rotating movement of a cylinder around its axis and a counter rotating orbital movement of the cylinder itself around an eccentric axis. The first type of movement is in fact very similar to that of a cylindrical container with a rotating endwall.Therefore the present research proposal has been formulated in three sets of experiments that will be carried in flows induced by three different types of rotational movements in a cylindrical container.On the one hand this methodology, with an analogy between three different flows investigated in the same geometry, should provide an original way to understand better the occurrences of flow instability and transitions from a general point of view, and will enable to assess the physical mechanisms determining mixing. On the other hand the present investigation aims at determining relevant parameters based on fluid mechanics aspect that will facilitate the process of scale up/down between stirred tank reactors and shaken flasks.

The proposed research study aims at investigating rotationally induced flows in cylindrical geometries to bring new insight on the type, nature and occurrence of flow transitions and instabilities as well as to offer novel information to better understand mixing mechanisms in related equipment and therefore develop and improve mixing modelling.Mixing is a physical phenomenon that is often encountered in everyday life. One of the simplest example is that of a spoon stirring a coffee cup to blend milk. Numerous applications can be found in the chemical and biochemical industries that utilise mixing of two or more phases or reactants.From this point of view several reactor designs can be distinguished that attain mixing in different ways: oscillatory flow mixers (OFM), static mixers, stirred vessels and shaking flasks. The last two types of reactors are rotationally induced mixing reactors for which a flow is generated by a stirring impeller or by the movement of the tray holding a cylindrical container along a circumferential orbit. The analogy between these two types of reactors is even more evident when considering that shaking flasks are often small scale mixers employed in the early stage of bioprocess development, before the developed process is implemented in a large scale industrial stirred tank.However, while the fluid mechanics of stirred tank reactors have been extensively studied, little is known about the flow patterns, flow transitions and instabilities taking place in shaken flasks. The consequences of this lack of knowledge are twofold: (a) a process developed in the shaken flasks cannot be fully characterised, undermining its reproducibility; (b) its operating conditions cannot be properly correlated to those present in industrial, scaled up reactors, usually stirred tanks, for which a vast amount of data is available in literature.Taking into account the differences in the flow geometry, certain types of instability and unsteadiness that are documented in the few papers dealing with fluid mechanics in shaken flasks, recall those that are encountered in a cylindrical container with a rotating endwall for which data is available in literature. The similarity between the two systems (i.e. shaking flask of cylindrical shape, and cylindrical container) is also indicated by the fact that the movement of the shaken flask can be seen as the superimposition of the rotating movement of a cylinder around its axis and a counter rotating orbital movement of the cylinder itself around an eccentric axis. The first type of movement is in fact very similar to that of a cylindrical container with a rotating endwall.Therefore the present research proposal has been formulated in three sets of experiments that will be carried in flows induced by three different types of rotational movements in a cylindrical container.On the one hand this methodology, with an analogy between three different flows investigated in the same geometry, should provide an original way to understand better the occurrences of flow instability and transitions from a general point of view, and will enable to assess the physical mechanisms determining mixing. On the other hand the present investigation aims at determining relevant parameters based on fluid mechanics aspect that will facilitate the process of scale up/down between stirred tank reactors and shaken flasks.

This research project deals with the study of flows and their control at different scales with a focus on turbulence and mixing. Turbulence occurs in oceans, in the atmosphere, in industrial processes. It could be simply described as a fluid flow which appears random in space and time and is unpredictable. Mixing is how flows fuse or separate. The picture of a river flow is used to illustrate turbulence and mixing along with the project's approach. The surface of the water presents a lot of eddies of different scales. If two small pieces of wood are thrown in such a flow, they will separate. If some ink is thrown, the stain will expand. To study turbulence one can either observe the flow at one point and summarize its fluctuations using statistical measures or draw a sketch of the flow to measure it (topological approach). The complexity of turbulence is that in this sketch everything changes all the time, so space-time information must be extracted. In addition, the sketch drawn from the river side is not the sketch drawn from one of the moving pieces of wood. This is the difference between the Eulerian (from the river side) and the Lagrangian (from within the flow) approaches. The Lagrangian approach is essential in turbulent flow decryption and physical modelling. It has various applications: flow control of drag, mixing, lift, cloud formation, atmospheric transport and combustion systems.Many central properties of the turbulence such as its enhanced dissipation and transfer of momentum, energy and mass, require the answer to the following question for their physically accurate modelling: How to link the flow sketch with the velocity in one point ; and the way the pieces of wood move with how the ink stain expands?A target of this project is to define some key points/areas in the flow which hold the flow's key properties. As you can expect from the broad range of eddy sizes, the key points will have different scales. To analyze how those key points are distributed on different scales we use fractal tools (as a tree where a big branch is connected to many small branches which are themselves connected to smaller ones and so on).Once such key points are identified and analysed, we aim at controlling them so as to guide the flow toward a turbulent-like state (under control) with specific desired configurations. There are different approaches concerning these key points in turbulent flow; an ambitious multi-scale flow control should integrate the control of the flow topology, energy, momentum, vorticity and acceleration in its approach.The research project offers a combined statistical, topological, Eulerian and Lagrangian approach by means of experiments and simulations grounded on novel theory.The heart of this project is the idea of generating bespoke multi-scale flows by use of electromagnetic forcing for the purpose of efficient mixing and multi-scale flow control which offers unprecedented opportunities for the study of turbulence. For this, I will develop laboratory experiments and simulations where I can create the entire flow by controlling chosen key points used in the theory. I already have demonstrated that it is possible to generate such a multi-scale flow with electromagnetic forces within a shallow layer brine flow, and to control it at will in space and time. I am now going to develop to its full potential the existing laboratory experiment. Various measurements will be performed (Eulerian and Lagrangian velocities, accelerations, dye concentrations, etc) and completed by numerical simulations. This will lead to results where all the aspects of turbulence and mixing will be analysed. Their applications to mixing enhancement should be obvious, whilst they should also lead to a broad multi-scale flow control approach, with implications for drag, lift and heat transfer.Turbulence and mixing are in the heart of many engineering works and environment issues, so this project will have a broad impact.