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This paper presents an analysis of providing a typical distillery with low carbon energy through the combination of local wind energy, solar PV, electricity storage and heat storage. The aim of this is to increase the sustainability of the energyintensive whisky industry. Using hourly local renewable resource data and typical distillery consumption information, the local energy generation is balanced against the demand at the time of use. This followed by load shifting using a battery and heat storage. Results show that significant carbon savings can be achieved by a carefully designed portfolio of hybrid generation, battery storage and heat storage.

Surge motion of a floating wind turbine can lead to conditions where the rotor moves backwards faster than the wind, leading to propeller-like conditions or vortex ring state (VRS). The effect of surge on the thrust of a floating turbine was investigated with OpenFOAM for conditions favourable to propeller and vortex ring state. Due to lower blade velocities and larger blade twists, a region of negative thrust is shown to extend spanwise from the blade root towards the tip signifying propeller state. Predictions that strong waves with low/moderate wind speeds leads to propeller-like conditions were confirmed for a representative surging simulation with a 9.4 m amplitude in waves with an 8.1 s period and 7 m/s wind speed. A negative thrust for the entire rotor, through the combination of an inboard region of negative and outboard region of small but still positive thrust, was observed during the expected part of the surging cycle. VRS was observed with blade tip-vortex interaction and root vortex recirculation due to the duration with a negative relative rotor velocity being similar to the blade passing period, inhibiting vortex advection downstream. This work explains and demonstrates the causes of propeller state and VRS for floating turbines.

Off-grid PV systems are providing critical access to energy services for millions of people throughout the globe. However, optimum sizing of these PV systems still poses a challenge, as inadequate system sizing could result in low system reliability and/or high cost of electricity generated. This paper presents a hybrid method of sizing off-grid PV systems for undefined electricity consumption. It then compares this sizing with off-grid PV systems installed in Nigeria – ranked the most populous electricity-deficit country in the world. The yields of the installed off-grid PV systems are also simulated for four major cities in Nigeria. Results show that for the over 1.5MWp of off-grid PV systems installed in the country, there is a potential 1.11 – 3.04 MWh of unutilised surplus electricity, which can supply 2hours of green electricity to at least 2,000 Tier-2 households during peak demand in the dry hot season. Thus, our hybrid model provides design and operational insight to off-grid PV system optimization.

The earth, a sphere consisting of several layers like an onion is still up to now not fully understood. Gaining the fundamental knowledge to understand the mystery of global cell formation and large-scale convection in the interior or at the surface e.g. in our atmosphere is still of great interest from a meteorological point of view and of course in geophysics. However, laboratory experiments are still exposed to a significant problem – gravity. Establishing a radial force field e.g. in a sphere or annulus is still overpowered by gravity unless the experiment is carried out in a microgravity environment. Here, we show a potential application of a central force field induced by magnetic forces that acts on a magnetic fluid in a rotating thermally heated annulus to induce thermomagnetic convection and waves that are similar to the baroclinic annulus with the focus to study large scale atmospheric flow fields in a small laboratory system. Thermomagnetic convection is based on non-isothermal variation of fluid magnetisation induced e.g. by a temperature gradient in the presence of an external magnetic field. After Currie’s law colder magnetic fluid exhibits a larger fluid magnetisation and is therefore attracted to higher magnetic field intensities. This phenomenon is used to induced convection in a thermally heated annulus filled with a magnetisable ferro-magnetic fluid. Here, we study a 2-dimensional numerical problem geometry where the fluid is cooled at the inner and heated at the outer cylinder. The system is forced with an increasing central force field such that colder fluid is attracted towards the outer boundary when a critical threshold is exceeded – the critical magnetic Rayleigh number an equivalent non-dimensional parameter to the classical Rayleigh number for natural convection. Numerical results are obtained for two different radii ratios (0.35, 0.5). The parametric study included a range of magnetic Rayleigh numbers between 103 to 7.5x105 to induce a range of thermomagnetic convective cases. In addition, the thermally annulus is rotated at different speeds expressed via the Taylor number ranging from 105 to 106. The observed flow fields reveal similar flow structures as seen in the classical baroclinic wave tank but have a different physically interpretation. The observed modes range from mode number 2 to 8 with stable symmetric to oscillatory and chaotic behaviours. The results are summarised in a regime diagram that is spanned in the thermally forcing and rotation speed space. This may be able to classify certain structures that are used to study atmospheric flow fields for different rotation and thermal forcing states e.g. planetary waves.

The baroclinic rotating annulus is a classic experiment to investigate the transition from regular waves to complex flows. A well documented transition via Amplitude Vacillation leads to low-dimensional chaos through a sequence of canonical bifurcations. However, the transition to geostrophic turbulence is usually through a regime of 'Structural Vacillation' (SV) which retains the overall spatial structure of regular waves but includes small-scale variability. Even though the SV vacillation occurs with a clear time scale, the dynamics of SV cannot usually be described by low-dimensional dynamics. For example, attractor dimension estimations tend to fail: they may not show any scaling region or converge to an unrealistic values. Explanations of the origin of SV have variously invoked higher radial modes of the fundamental baroclinic waves, local secondary instabilities in the baroclinic waves caused by high thermal gradients (gravity waves) or velocity shear (barotropic instability), or instabilities within the side-wall (Stewartson) boundary layers.The aim of this paper is to identify where within the fluid different signals of variability are located at different stages in the transition from a steady wave to pronounced SV. To this end, a set of experiments in a water-filled rotating annulus with a free surface (inner radius 45 mm, outer radius 120 mm, fluid depth 140 mm) was carried out covering a temperature difference between the heated outer wall and the cooler inner wall of between 6 and 9.5 K, and a range of rotation rates from 0.84 to 2.29 rad/s (Ta= 4.75 x 107 - 3.53 x 108 and Θ = 0.0617 - 0.629). The flow was observed through an infrared camera capturing the temperatures of the free surface. Images of the flow were recorded for a period of 15 minutes at a sampling rate of 1 Hz at the lower rotation rates and 2 Hz at the higher rotation rates.The initial processing of the time series of temperature images involved normalisation of the temperatures followed by rotation of the images to a coordinate system co-rotating with the main baroclinic wave mode. The resulting images were separated into the time-mean wave field and the fluctuation field, resulting in a set of normalised temperature fluctuations at fixed points relative to the main baroclinic wave. Each of the time series was then used to calculate the power spectrum at that location. The low-frequency part of the spectra (up until half the tank rotation frequency) was used in a k-means cluster analysis to identify clusters of similar spectral shape and, from this, create a map of which spectral shape was found at which location in the flow field.The results show isolated locations of a high frequency peak near the inner boundary at the onset of visible fluctuations. Further into the regime of clear structural vacillations, areas of pronounced variability at lower frequencies become visible at the lee shoulder of the cold jets in the fluid interior, followed by activity where the end of the cold jet interacts with the hot jet emanating from the outer boundary layer.

Reliable access to electricity is still a challenge in many developing countries. Indeed, rural areas in sub-Saharan Africa and developing countries such as India still encounter frequent power outages. Local energy markets (LEMs) have emerged as a low-cost solution enabling prosumers with power supply systems such as solar PV to sell their surplus of energy to other members of the local community. This paper proposes a one-to-one automated negotiation framework for peer-to-peer (P2P) local trading of electricity. Our framework uses an autonomous agent model to capture the preferences of both an electricity seller (consumer) and buyer (small local generator or prosumer), in terms of price and electricity quantities to be traded in different periods throughout a day. We develop a bilateral negotiation framework based on the well-known Rubinstein alternating offers protocol, in which the quantity of electricity and the price for different periods are aggregated into daily packages and negotiated between the buyer and seller agent. The framework is then implemented experimentally, with buyers and sellers adopting different negotiation strategies based on negotiation concession algorithms, such as linear heuristic or Boulware. Results show that this framework and agents modelling allow prosumers to increase their revenue while providing electricity access to the community at low cost.

Convection of a magnetic fluid within a perspex container was investigated experimentally and complemented by a computational Finite-Element model built according to the same physical specification. The enclosure was heated at two opposite side walls and exposed to a magnetic field provided by a Neodymium-Iron-Boron permanent magnet placed either above or below the container. The spatial temperature distribution on the front side wall of the container was recorded via infrared thermography (IR) and compared to computational results that reproduced the spatial temperature fields. The results show a significant effect on heat transfer by the location of the permanent magnet and gave evidence that the Kelvin body force can be much stronger than buoyancy. As both body forces are temperature sensitive an increase in temperature difference increased both, buoyancy and Kelvin body force, albeit with a different intensity that was explained via Curie's Law and expressed as a temperature dependent magnetisation through the pyromagnetic coefficient, K. The heat transfer was characterised by the Nusselt number and a suitable modified Rayleigh number that took the orientation of both buoyancy and Kelvin body force in account. The degree of heat transfer enhancement reported varied between a 23% reduction to a 20% enhancement.

Magnetic fluid flow and heat transfer by natural and thermomagnetic convection was studied numerically in a square enclosure. The aim was to investigate the transition from natural convection to thermomagnetic convection by exploring situations where buoyancy and the Kelvin body force would be opposing each other such that the magnetic effects would in some cases be the dominant factor throughout the domain and in other cases only in a part of the fluid. The numerical model coupled the solution of the magnetostatic field equation with the heat and fluid flow equations to simulate the fluid flow under a realistic magnetic field generated by a permanent magnet. The results suggest that the domain of influence over the flow field is largely aligned with the domain of dominance of the respective driving force. The result is that the transition from a single buoyancy-driven convection cell to a single thermomagnetically driven cell is via a two-cell structure and that the local effect on the flow field leads to a global effect on the heat transfer with a minimum of the Nusselt number in the transition region.

Renewable energy has achieved high penetration rates in many areas, leading to curtailment, especially if existing network infrastructure is insufficient and energy generated cannot be exported. In this context, Distribution Network Operators (DNOs) face a significant knowledge gap about how to implement curtailment rules that achieve desired operational objectives, but at the same time minimise disruption and economic losses for renewable generators. In this work, we study the properties of several curtailment rules widely used in UK renewable energy projects, and their effect on the viability of renewable generation investment. Moreover, we propose a new curtailment rule which guarantees fair allocation of curtailment amongst all generators with minimal disruption. Another key knowledge gap faced by DNOs is how to incentivise private network upgrades, especially in settings where several generators can use the same line against the payment of a transmission fee. In this work, we provide a solution to this problem by using tools from algorithmic game theory. Specifically, this setting can be modelled as a Stackelberg game between the private transmission line investor and local renewable generators, who are required to pay a transmission fee to access the line. We provide a method for computing the empirical equilibrium of this game, using a model that captures the stochastic nature of renewable energy generation and demand. Finally, we use the practical setting of a grid reinforcement project from the UK and a large dataset of wind speed measurements and demand to validate our model. We show that charging a transmission fee as a proportion of the feed-in tariff price between 15%-75% would allow both investors to implement their projects and achieve desirable distribution of the profit., Comment: Preprint of final submitted version

Thermomagnetic convection was investigated experimentally by infrared thermography and validated numerically by a finite-element analysis. A cavity filled with a magnetic liquid was under the influence of a permanent magnet that provided an external magnetic field and was subjected to thermal forcing by maintaining the two opposite horizontal walls at different temperatures. All configurations were chosen to explore situations where the Kelvin body force and buoyancy would either oppose each other or act perpendicular to each other. As both body forces depend on temperature, the aim was to explore the degree by which heat transfer may be enhanced by only varying the temperature difference. The results demonstrate that the Kelvin body force, which can be much stronger than buoyancy, leads to convective flow where only conduction would occur without the presence of the magnet. An effective force ratio, r , is developed which suggests that an increase in temperature difference across the cavity initially leads to a dominance of thermomagnetic forcing over buoyancy but that the overall force balance becomes more moderate at higher temperature differences. The global effect of both body forces on heat transfer was characterised by the Nusselt number and a suitable modified Rayleigh number.

Shipping is a vital industry for the global economy. Stability of ships, provided by ballast water, is a crucial factor for cargo loading and unloading processes. Ballast water treatment has practical significance in terms of environmental issues, ecosystem, and human health, because ships discharge this water into the environment before loading their cargos. This study reviews the common methods for ballast water management – exchange, heating, filtration, ultrasonic treatment, ultraviolet irradiation, chemicals, and gas supersaturation – to select the best one. This study compares water temperature, salinity, dissolved oxygen, polycyclic aromatic hydrocarbons (PAHs), and heavy metals (Co, Cr, Ni, Pb) for ballast tanks of selected ships with the recipient port environment in the Persian Gulf as a case study. The exchange of ballast water in the ocean and/or its treatment on board to prevent inadvertent effects on the environment's physicochemical conditions is related to vessel characteristics, legislation, and the environmental condition. Ecological risk study showed that the salt content in ballast water is close to that of seawater, but the values of Cr (2.1 mg/l) and Ni (0.029 mg/l) in ballast water are higher than those in seawater (1 and 0.004 mg/l, respectively).

Electricity-access is a growing concern in developing countries of Sub-Saharan Africa where approximately 563million people (8% of the global population) lack electricity. Many use fossil-fuel generators and/or solar-home-systems (SHSs) with storage. Given the observed excess and unutilized electricity generated from these SHSs, a novel community peer-to-peer (P2P) electricity-market using automated negotiations is presented as a solution to improve access to electricity. Software agents representing World Bank Tiers 1 – 4 electricity-access households bilaterally negotiate electricity price and quantities applying five different negotiations heuristics. Simulation results show 65 – 100% trade of the excess generation; with Tiers 1 – 2 (low-income households) negotiating sufficient electricity (1 – 1.1kWh/day) at the least market-price of £0.35/kWh to move to Tier 3. Likewise, the Tier 3 household agent negotiated 1.5kWh/day sufficient to meet its needs. This novel electricitymarket model can help drive the United Nations goal of affordable, sustainable and modern energy for all by 2030.

The enhancement of Measure Correlate Predict (MCP) using Principal Component Analysis (PCA) is a new wind prediction method based on studying the patterns of historical wind data. The method is trained based on past wind data to predict the wind speed using an ensemble of similar past events. The method is tested based on Meteorological Office (MET-Office) wind speed from a reference site that spans from 2000 to 2010. The last two years (2009 to 2010) were used as training years where the MCP – PCA algorithm learns the wind patterns between the reference(s) and target(s) site. The prediction result is then compared to the actual wind speed distribution at the target site of the training years. The method is further tested with an increase in number of reference sites for predictions. The new prediction results show that the prediction error improves to 23.1 % in average in comparison to a standard linear regression method.

Fluctuations in solar irradiance were varied in frequency and magnitude to investigate the performance of a directly-connected solar energy powered reverse osmosis (RO) membrane system. Typically, the system produced acceptable quality water with constant solar irradiances ranging from 400 to 1200 W m −2 . Low average motor powers were encountered during fluctuations, however, in many cases, good performance was still realised, even at solar irradiance values that were equivalent to −2 . This counter-intuitive result arises from the effect of averaging the motor power, with periods of high solar irradiance compensating for the under-performance at times when the system was off. Overall, even though the permeate flux was often low when operating under fluctuating conditions, the RO system continued to deliver satisfactory quality water and at a low specific energy consumption (SEC). Temporal studies revealed that a disruption of the concentration polarisation layer occurs via a naturally induced backwash for steps in the solar irradiance as low as 100 W m −2 . This suggests that a renewable energy powered RO filtration system could benefit from being operated from a fluctuating energy source. Furthermore, the operating conditions during the first couple of minutes after a system shutdown event is shown to be very important, with: (i) shorter off-periods resulting in good performance being achieved quicker, and (ii) short-term power availability dramatically improving system performance. These findings indicate that a renewable energy powered RO system can operate well from a fluctuating energy source, in particular when additional power – for example, via supercapacitor energy buffering – is available to boost the system after a shut-down period.

We present a new statistical wind forecasting tool based on Principal Component Analysis (PCA), which is trained on past data to predict the wind speed using an ensemble of dynamically similar past events. At the same time the method provides a prediction of the likely forecasting error. The method is applied to Meteorological Office wind speed and direction data from a site in Edinburgh. For the training period, the years 2008–2009 were used, and the wind forecasting was tested for the data from 2010 for that site. Different parameter values were also used in the PCA analysis to explore the sensitivity analysis of the results. The forecasting results demonstrated that the technique can be used to forecast the wind up to 24 h ahead with a consistent improvement over persistence for forecasting more than 10 h ahead. The comparison of the forecasting error with the uncertainty estimated from the error growth in the ensemble forecast showed that the forecasting error could be well predicted.

The personalized diagnosis, assistance and evaluation of students in open learning environments can be a challenging task, especially in cases that the processes need to be taking place in real-time, classroom conditions. This paper describes the design of an open learning environment under development, designed to monitor the comprehension of students, assess their prior knowledge, build individual learner profiles, provide personalized assistance and, finally, evaluate their performance by using artificial intelligence. A trial test has been performed, with the participation of 20 students, which displayed promising results.

The thrust generation by electro-hydrodynamic (EHD) effect has been studied for a wire-cylinder arrangement under high DC voltage. Series of measurements have been conducted in order to determine the relationship between generated thrust and corona discharge current, as well as its dependence on geometrical characteristics of the electrodes, e.g. electrode gap, wire and cylinder radii. The experimental investigation has shown a linear relationship between the generated thrust and the discharge current, while parametric analysis showed that increased electrode gap and emitter radius reduces the thrust. On the other hand, large gaps favor the thrust per unit power ratio.

The effect of wind turbine wakes in large offshore wind energy arrays can be a substantial factor in affecting the performance of turbines inside the array. Turbulent mixing plays a key role in the wake recovery, having a significant effect on the length over which the wake is strong enough to affect the performance of other turbines significantly. We highlight how turbulence affects wind turbine wakes using results from LES simulations of Lillgrund offshore wind farm in the context of SCADA data selected to mirror the wind conditions simulated. The analysis here concentrated on temporal spectra of wind velocities measured by the turbine's nacelle anemometer and calculated at the turbine locations in the computational model. The effect of the wind turbine rotor on the downstream flow is quantified by analysing the change in spectral features of turbines within the wind farm compared to turbines at the side of the farm exposed to the wind.

The relative merits of three contrasting empirical orthogonal decomposition methods in common use (namely, Proper Orthogonal Decomposition, Biorthogonal Decomposition and Multivariate Singular Systems Analysis) are considered as applied to baroclinic flow data. The regimes analysed are a steady, drifting wave, a modulated amplitude vacillating wave flow and a neighbouring multi-mode state which exhibits intermittency. The results are used to make a qualitative comparison of the methods in terms of convergence properties, variance capture and eigenfunction structure. The feasibility of using the resulting empirical orthogonal functions to transform partial differential equations to ordinary differential equations by Galerkin projection is mentioned. © 1997 Elsevier Science B.V.

This study investigates the potential role of electric vehicles in an electricity network with a high contribution from variable generation such as wind power. Electric vehicles are modelled to provide demand management through flexible charging requirements and energy balancing for the network. Balancing applications include both demand balancing and vehicle-to-grid discharging. This study is configured to represent the UK grid with balancing requirements derived from wind generation calculated from weather station wind speeds on the supply side and National Grid data from on the demand side. The simulation models 1000 individual vehicle entities to represent the behaviour of larger numbers of vehicles. A stochastic trip generation profile is used to generate realistic journey characteristics, whilst a market pricing model allows charging and balancing decisions to be based on realistic market price conditions. The simulation has been tested with wind generation capacities representing up to 30% of UK consumption. Results show significant improvements to load following conditions with the introduction of electric vehicles, suggesting that they could substantially facilitate the uptake of intermittent renewable generation. Electric vehicle owners would benefit from flexible charging and selling tariffs, with the majority of revenue derived from vehicle-to-grid participation in balancing markets.

We present an analysis of the ability to predict the power output from a nominal wind turbine or wind farm a few hours ahead using only locally available data - either the current and recent wind speed or power output. A third method combines the current state with knowledge of the long-term climatology. The wind speed data were taken from a 46-year long record of hourly readings at a Scottish coastal site and converted to power output and electricity production using a generic wind turbine power curve. The wind speed data or the calculated power output at a given time were used to predict the output a few hours ahead, either using persistence, a linear model, or a model based on the mean daily cycle extracted from the long-term record. Since many wind farm operators base their forecast on current wind speed or output measures alone, this analysis will provide some quantification of the quality of this approach, either to help them plan their operation or be able to put these simple methods in quantitative context of more complex methods.

A microturbine is developed for harnessing energy from an airflow, which is generated by body motion. The energy should get transformed into usable electrical energy and thus provided for powering portable electrical devices. The turbine is flown axial and rotates in the same direction independent of the incoming airflow. Different designs of the turbine are tested and opposed to figure out the best parameters. For the best turbine, the integration and the process of walking is simulated.

Rotational augmentation is a well-known phenomenon of rotating aerofoils on wind turbines and helicopters where the lift or torque is improved compared to that of stationary aerofoils. We present an analysis which is based on the concept of a developing boundary layer and the Ekman boundary layer using a 3D Finite-Element Analysis of the developing laminar boundary layer over a flat plate in a rotating frame of reference. A parametric analysis addresses the Reynolds number, the Ekman number and the speed ratio in turn. The results demonstrate that the surface's rotation limits the boundary layer to the thinner of the two boundary layers, and that it induces a span-wise flow in the radial direction which in turn leads to Ekman suction. This Ekman suction provides a mechanism to counteract an adverse pressure gradient and thus prevent stall. The criterion derived from this was successfully applied and tested against observations and full CFD results.

The energy planning problem becomes increasingly important during the recent years mainly due to the pressing needs that need to be taken into account in terms of economic, environmental and social aspects. At the same time, technology supports many options and alternative solutions in the design of energy and fuel supply chains (SCs), based on more holistic approaches that have their origin in the production management. Considering the introduction of an integrated framework of evaluation for alternative energy supply options, the present work applies a RTN (Resource Task Network) based representation of the Energy SCs (ESCs) along with a mathematical programming optimisation model in order to analyse and model a location specific energy planning problem. Special emphasis is given to fuel mix optimisation in terms of maximising the economic, social and environmental performance of ESCs. Furthermore, the interaction between aspects and implications under the existing limitations both in the design and technical characteristics of the system as well as in the environmental / air quality limitations, will be also revealed. On top of the results obtained, the present work’s added value relates to the development of the proposed model for the analysis of various energy planning scenarios, comprising in this way a very useful decision making tool.

Constant-temperature hot-film anemometry measurements in a two-layer system of a silicone fluid layer over a magnetic fluid layer has been investigated. Complicating factors potentially affecting the measurements were very slow velocities, the unusually high thermal conductivity of the magnetic liquid, the vicinity of solid boundaries, the presence of the interface, and the possibility of magneto-convection in addition to natural convection. All these factors required a calibration procedure combining both experimental calibration and a set of numerical models of the system. The findings obtained during the calibration were that neither natural convection nor magneto-convection were adversely affecting the measurements, probably due to the effects of the solid boundaries and the interface. It was furthermore observed that the fluid interface resulted in an effect analogous to the near-wall effect, but deformations of the interface due to the sensor or its mounting prevented measurements close to the boundary. Spatial variation of the fluid velocities affected the calibration of the sensor noticeably. While a simple calibration, either by moving the probe or by assuming a uniform velocity, can give a qualitatively reasonable velocity profile, it will quantitatively deviate significantly from the true velocities.

An experimental study on the instability of a detached Stewartson layer, using an annular, rotating tank with flat, rigid upper and lower boundaries, showed an instability to steady vortices at a critical Reynolds number, arranged in a global mode structure along the shear layer. Increasing the Reynolds number resulted in successive transitions to lower modes where time-dependent behaviour was only found for flows with three or less vortices. Previous numerical simulations of a related experiment, using a two-dimensional spectral model of the quasi-geostrophic vorticity equation incorporating Ekman forcing and viscous dissipation, suggested that the boundary conditions at the inner cylinder of the domain could significantly affect the interior flow by the generation and shedding of vorticity at this inner boundary. A comparison of the numerical results with experimental data suggests that the rise of time-dependent behaviour is due to vorticity generation at the inner domain boundary.

Taylor-Couette flow with superimposed axial flow is becoming increasingly accepted as a novel reactor type offering a wide range of mixing regimes within a single reactor vessel, depending on the operating conditions of the reactor. To exploit the potential of such a reactor fully, the mixing processes in the reactor have to be well understood. A variant of an established model to simulate flow in a Taylor-Couette reactor with axial flow is presented. The model, which is based on the description of the flow as a linked network of stirred tanks, attempts to develop a parameterisation of the mass exchange processes between Taylor vortices and the by-pass stream on a rational basis. Some numerical results are presented and compared with results from the literature.

We investigate drag forces on liquids pumped through a duct coated with a magnetic liquid of kinematic viscosity of 1.69 cSt. Due to a suitable arrangement of a set of permanent magnets, the magnetic liquid formed a fluid layer on the bottom of a square duct through which a silicone oil with a kinematic viscosity of 50 cst was pumped. Applied magnetic flux densities ranged from less than 0.01 T to about 0.15 T at the surface of the magnets. The influences of the strength and gradient of the magnetic field, and of the fluid flow rate, on the shape of the magnetic fluid have been investigated. It is not practical to form a uniform magnetic fluid layer under our experimental conditions, and consequently the drag was increased compared with the uncoated case because the flow of the silicone fluid over the magnetic fluid layer deformed this layer dramatically. For a viscosity ratio between the main flow and the ferrofluid less than about 30, it is therefore not feasible to use a magnetic fluid layer to reduce the drag in a duct. However, the generally high thermal conductivity of magnetic liquids, its convection, and interface deformation, might be exploited for heat transfer enhancement