Philip Clausen

Philip Clausen
The University of Newcastle, Australia · School of Engineering

PhD

About

78
Publications
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2,529
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Publications

Publications (78)
Preprint
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11 This paper investigates the operation and loading of a 5 kW HAWT using the aeroelastic code 12 FAST. Wind data from built environment site at Port Kennedy (PK) and from a flat terrain site in 13 Östergarnsholm (OG), are analysed and compared with IEC 61400-2. The longitudinal turbulence 14 intensity (TIu) in the PK wind field was 22%; which was...
Article
Commercially available high-speed multi-channel data acquisition systems can be expensive to purchase and are generally difficult to tailor to specific applications. Arduino is an open-source prototyping platform that facilitates the design and build of computer controlled systems for a wide variety of uses. This article describes in detail several...
Article
The installation of small wind turbines and solar photovoltaic (PV) modules in the built environment requires a detailed understanding of wind resources to maximise turbine power output and minimise damage due to wind loading. While urban sites are known to be highly turbulent, less is known about the composition and frequency of gust events. To da...
Article
Full-text available
This paper investigates the operation and loading of a 5 kW HAWT using the aeroelastic code FAST. Wind data from built environment site at Port Kennedy (PK) and from a flat terrain site in Östergarnsholm (OG), are analysed and compared with IEC 61400-2. The longitudinal turbulence intensity (TIu) in the PK wind field was 22%; which was higher than...
Chapter
This paper briefly describes the optimisation method and presents the results of the theoretical structural optimisation of a small wind turbine blade. The bi-directional evolutionary layout optimisation method was applied to the design of a 3D printed blade suitable for a diffuser augmented wind turbine. The turbine blades were manufactured (print...
Chapter
This paper presents measurements and predictions of the yaw performance of a small 5 kW horizontal-axis wind turbine operating in unsteady flow fitted with a delta wing tail fin of two different sizes. Measurements show the smaller of the two tail fins causes the turbine to operate at a higher mean yaw error than the larger tail fin and to respond...
Chapter
This paper outlines the development of a novel instrumented system that allows the mechanical separation and measurement of the torque and thrust loads on the individual blades of a small two-bladed horizontal axis wind turbine. The siting of small wind turbine systems in the built environment is often accompanied by highly turbulent and unsteady w...
Chapter
Small wind turbines are usually sited in more complex environments than the open terrain sites, such as urban built environment. However, the international small wind turbine design standard IEC61400.2 is based on the measurements of flat and open terrain. Failures of SWTs operational in urban area predicts the inadequacy of turbine design for the...
Article
Aeroelastic modelling is regularly used in the design and analysis of commercial scale wind turbines, but has seen comparatively little use in the development of small wind turbines. Fewer studies still have considered experimental validation of model performance with field measurements. This study details the development of an aeroelastic model of...
Article
It is well known that wind turbine blades are fatigue critical, with much literature and methodologies available for assessing fatigue loading of large wind turbine blades. Little research effort has been directed at assessing the fatigue life of small wind turbines which operate at higher rotational speeds and are subject to highly unsteady aerody...
Article
Full-text available
The striking resemblance of long-snouted aquatic mammals and reptiles has long been considered an example of morphological convergence, yet the true cause of this similarity remains untested. We addressed this deficit through three-dimensional morphometric analysis of the full diversity of crocodilian and toothed whale (Odontoceti) skull shapes. Ou...
Article
Detailed computational fluid dynamics simulations for the rostrum of three species of sawfish (Pristidae) revealed that negligible turbulent flow is generated from all rostra during lateral swipe prey manipulation and swimming. These results suggest that sawfishes are effective stealth hunters that may not be detected by their teleost prey's latera...
Article
Full-text available
Traditionally, the optimisation of a Diffuser Augmented Wind Turbine has focused on maximising power output. However, due to the often less than ideal location of small-scale turbines, cut-in speed and starting time are of equal importance in maximising Annual Energy Production, which is the ultimate goal of any wind turbine design. This paper prop...
Article
Full-text available
This paper presents a method to optimise the material layout of a fibreglass-reinforced composite constructed small wind turbine blade. The method was developed with the intent of reducing blade mass without compromising the blade’s structural performance or longevity. The bi-directional evolutionary layout optimisation method utilises finite eleme...
Article
Full-text available
This paper investigates the applicability of the assumed wind fields in International Electrotechnical Commission (IEC) standard 61400 Part 2, the design standard for small wind turbines, for a turbine operating in the built environment, and the effects these wind fields have on the predicted performance of a 5 kW Aerogenesis turbine using detailed...
Article
Full-text available
Small horizontal-axis wind turbines are likely to operate in a broad range of operating flow conditions, often in highly turbulent flow, due, in part, to their varied site placements. This paper compares the computational simulations of the performance of a 5 kW horizontal-axis wind turbine to detailed field measurements, with a particular focus on...
Article
Full-text available
Spider orb-webs are the ultimate anti-ballistic devices, capable of dissipating the relatively massive kinetic energy of flying prey. Increased web size and prey stopping capacity have co-evolved in a number orb-web taxa, but the selective forces driving web size and performance increases are under debate. The rare, large prey hypothesis maintains...
Article
Small wind turbines are usually installed to provide off-grid power and as such can be situated close to the load in a less-than-ideal wind resource. These wind regimes are often governed by low mean speeds and high wind turbulence. This can result in energy production less than that specified by the manufacturer's power curve. Wind turbulence is d...
Article
Full-text available
Skull structure is intimately associated with feeding ability in vertebrates, both in terms of specific performance measures and general ecological characteristics. This study quantitatively assessed variation in the shape of the cranium and mandible in varanoid lizards, and its relationship to structural performance (von Mises strain) and interspe...
Article
Full-text available
The most stable pattern of internal fixation for mandibular condyle fractures is an area of ongoing discussion. This study investigates the stability of three patterns of plate fixation using readily available, commercially pure titanium implants. Finite element models of a simulated mandibular condyle fracture were constructed. The completed model...
Article
Full-text available
Finite element analysis (FEA) is a computational technique of growing popularity in the field of comparative biomechanics, and is an easily accessible platform for form-function analyses of biological structures. However, its rapid evolution in recent years from a novel approach to common practice demands some scrutiny in regards to the validity of...
Chapter
Small wind turbine blades share a number of features with large blades, but have some important differences. The two main differences are their much higher rotational speed, which causes more fatigue cycles and higher yaw moments, and their operation at low Reynolds number, which means that thick aerofoil sections cannot be used near the root. This...
Chapter
Introduction Modelling of the Mould Results Discussion Conclusions
Article
Full-text available
Questions surrounding the dramatic morphology of saber-tooths, and the presumably deadly purpose to which it was put, have long excited scholarly and popular attention. Among saber-toothed species, the iconic North American placental, Smilodon fatalis, and the bizarre South American sparassodont, Thylacosmilus atrox, represent extreme forms commonl...
Data
Text S1, Body mass estimates. Figure S1, Variations in canine bite reaction force (BF) and jaw muscle recruitment (MR) with changing gape angle. Table S1, Inputs for Finite Element Model of Smilodon fatalis. Table S2, Inputs for Finite Element Model of Thylacosmilus atrox. Table S3, Inputs for Finite Element Model of Panthera pardus. Table S4, Mean...
Article
Full-text available
Crocodilians exhibit a spectrum of rostral shape from long snouted (longirostrine), through to short snouted (brevirostrine) morphologies. The proportional length of the mandibular symphysis correlates consistently with rostral shape, forming as much as 50% of the mandible's length in longirostrine forms, but 10% in brevirostrine crocodilians. Here...
Article
The most stable pattern of internal fixation for fractures of the mandibular condyle is a matter for ongoing discussion. In this study we investigated the stability of three commonly used patterns of plate fixation, and constructed finite element models of a simulated mandibular condylar fracture. The completed models were heterogeneous in the dist...
Article
Full-text available
In recent years, finite element analysis (FEA) has been increasingly applied to examine and predict the mechanical behaviour of craniofacial and other bony structures. Traditional methods used to determine material properties and validate finite element models (FEMs) have met with variable success, and can be time-consuming. An implicit assumption...
Article
Full-text available
Historically, predicting ursid feeding behaviour on the basis of morphometric and mechanical analyses has proven difficult. Here, we apply three‐dimensional finite element analysis to models representing five extant and one fossil species of bear. The ability to generate high bite forces, and for the skull to sustain them, is present in both the gi...
Article
The aim of this study was to determine the variability of the thrust parameters produced by practitioners performing a high velocity spinal manipulative therapy technique (toggle-recoil) normally applied to the neck. Fourteen participants performed three thrust trials, separated by >30minutes, on a patient simulation device. Force and displacement...
Article
Full-text available
The predatory ecology of Varanus komodoensis (Komodo Dragon) has been a subject of long-standing interest and considerable conjecture. Here, we investigate the roles and potential interplay between cranial mechanics, toxic bacteria, and venom. Our analyses point to the presence of a sophisticated combined-arsenal killing apparatus. We find that the...
Article
This paper describes measurements of the shape of a 900 mm long, hand-carved timber blade for a 500 W three-bladed horizontal axis wind turbine. Four blades were hand-carved in Nepal by reference to a master blade cut in Australia on a numerically controlled milling machine. A high definition three-dimensional scanner was used to determine the surf...
Article
The notorious jaws of the white shark Carcharodon carcharias are widely feared, yet poorly understood. Neither its bite force, nor how such force might be delivered using relatively elastic cartilaginous jaws, have been quantified or described. We have digitally reconstructed the jaws of a white shark to estimate maximum bite force and examine rela...
Article
We present results from a detailed three-dimensional finite element analysis of the cranium and mandible of the Australian dingo (Canis lupus dingo) during a range of feeding activities and compare results with predictions based on two-dimensional methodology [Greaves, W.S., 2000. Location of the vector of jaw muscle force in mammals. Journal of Mo...
Article
Full-text available
The Komodo dragon (Varanus komodoensis) displays a unique hold and pull-feeding technique. Its delicate 'space-frame' skull morphology differs greatly from that apparent in most living large prey specialists and is suggestive of a high degree of optimization, wherein use of materials is minimized. Here, using high-resolution finite element modellin...
Article
Full-text available
Models of the mammalian jaw have predicted that bite force is intimately linked to jaw gape and to tooth position. Despite widespread use, few empirical studies have provided evidence to validate these models in non-human mammals and none have considered the influence of gape angle on the distribution of stress. Here using a multi-property finite e...
Article
Full-text available
Models of the mammalian jaw have predicted that bite force is intimately linked to jaw gape and to tooth position. Despite widespread use, few empirical studies have provided evidence to validate these models in non-human mammals and none have considered the influence of gape angle on the distribution of stress. Here using a multi-property finite e...
Article
This paper describes measurements of the root bending moment on a three-bladed 500 W horizontal-axis wind turbine, which were obtained using a purpose-built rotating data acquisition system. The main aim was to investigate the moment when the turbine was yawing in response to wind direction changes, particularly when the yaw rate zoas large. This s...
Article
Full-text available
The extinct marsupial thylacine (Thylacinus cynocephalus) and placental grey wolf (Canis lupus) are commonly presented as an iconic example of convergence. However, various analyses suggest distinctly different behaviours and specialization towards either relatively small or large prey in the thylacine, bringing the degree of apparent convergence i...
Article
Full-text available
The American sabercat Smilodon fatalis is among the most charismatic of fossil carnivores. Despite broad agreement that its extraordinary anatomy reflects unique hunting techniques, after >150 years of study, many questions remain concerning its predatory behavior. Were the "sabers" used to take down large prey? Were prey killed with an evisceratin...
Article
In vivo data demonstrates that strain is not distributed uniformly on the surface of the primate skull during feeding. However, in vivo studies are unable to identify or track changes in stress and strain throughout the whole structure. Finite element (FE) analysis, a powerful engineering tool long used to predict the performance of man-made device...
Article
The work described in this paper compares the measured blade root flapwise bending moment on a 400W 3-bladed wind turbine to analytical predictions and calculations from the "simple load model" of the international Electrotechnical Commission safety standard for small wind turbines. The predictions use the method of Eggleston and Stoddard (1987) an...
Article
This paper presents some dynamic measurements acquired from the surface of a composite constructed test blade on an operating 400W three-bladed wind turbine. The structural design of the composite blade was modified from the original design to reduce its stiffness in flapwise bending. Signals from 10 strain gauges attached to the blade were acquire...
Article
This article reports the use of simple beam and finite-element models to investigate the relationship between rostral shape and biomechanical performance in living crocodilians under a range of loading conditions. Load cases corresponded to simple biting, lateral head shaking, and twist feeding behaviors. The six specimens were chosen to reflect, a...
Article
This paper details a formulation to create a fatigue loading procedure for the blade of a small wind turbine using a combination of detailed short-term aeroelastic and wind measurements and averaged long-term wind data from the Australian Bureau of Meteorology. Detailed aeroelastic measurements from the blade of an operating small wind turbine were...
Article
This paper presents and discusses a new fatigue damage accumulation model for Glass Fibre Reinforced Plastics under step loading. This model was formulated from a single-step constant amplitude fatigue model previously developed by the authors. Fatigue damage is defined and quantified in this paper. The model was tested using independent experiment...
Article
This paper explores technical and other issues arising from using shaped timber for a 1 metre long high efficiency blade for a small 600 W wind turbine. Two readily available Australian grown softwood timber species, radiata pine and hoop pine, were selected. Reasons for selecting these timbers are detailed in the paper. The fatigue life of the bot...
Article
Full-text available
A 2.5m long glass fibre reinforced plastic composite wind turbine blade was fatigue tested by means of a mechanically operated test rig. The rig uses a crank eccentric mechanism to flex the blade by a constant displacement in the flapwise direction for each load cycle. A yearly fatigue-loading spectrum for the blades has been developed from using s...
Article
Current models used to predict the fatigue life of glass fibre-reinforced plastic composites do not accurately consider the effects of load stress ratios and load frequencies. These models usually require significant amount of experimental data to establish a set of characteristic fatigue curves for a given composite. This paper proposes a fatigue...
Article
This paper presents analytical and computational predictions of the performance of an operating 2.5 m long composite wind turbine blade and compares these predictions with the results of detailed measurements. Part 1 of this paper describes in detail the important aspects of the 5 kW wind turbine, the experimental equipment and data acquisition pro...
Article
Undertaking a dynamic finite element analysis on a tank containing a fluid either requires both the fluid and tank to be modelled or the mass of the vessel's walls and base to be adjusted to account for the presence of the fluid. The former generally requires specialized solid elements to model the fluid, which are not available in all finite eleme...
Article
This paper presents and considers dynamic structural measurements from the blade of an operating 5 kW wind turbine. One of the turbine's 2.5m long composite blades was instrumented with strain gauges at several locations along its length with signals acquired through a novel capacitive coupling device to a stationary computer. Data were acquired fr...
Article
This paper reviews some recent advances in the technology of small wind turbines, whose upper power limit we take arbitrarily as 50 kW. Small turbines are used mainly for remote power generation either alone or in conjunction with other energy sources and battery storage. They can be divided into three categories: micro, up to 1kW; mid-range; and m...
Article
This paper discusses some of the major research and development issues for small wind turbines whose upper power limit we take arbitrarily as 50 kW. The basis for the comparison is the mature technology available for large turbines which has yet to be fully diffused downwards. After defining and categorising the important features of small turbines...
Article
This paper presents and discusses the results of detailed strain gauge measurements taken from the surface of a composite blade on a small horizontal-axis wind turbine. We believe that these are the first such measurements to be taken on a small wind turbine. The two-bladed upwind machine is located adjacent to Fort Scratchley, a historic seaside l...
Article
This paper describes preliminary work to optimise the use of material in a 2.5 m long fibreglass composite wind turbine blade. A program was written to create a detailed finite element mesh of the blade, using design data from blade element theory and panel code predictions, in a format suitable for direct input into a commercially available finite...
Article
This paper presents measurements in the turbulent wake of a circular cylinder rotating with its axis normal to the free-stream velocity; in other words, the axis of rotation was parallel to the streamwise direction. All three mean velocities and six Reynolds stresses were obtained at three positions downstream of the cylinder, with and without rota...
Article
Measurements were made of the swirling boundary layer developing in a conical diffuser with a 20° included angle and an area ratio of 2.84. The inlet swirl was close to solid-body rotation and was of sufficient magnitude to prevent boundary layer separation but just insufficient to cause recirculation in the core flow. A single hot-wire was travers...
Article
Effects of swirl on the development of an axisymmetric turbulent mixing layer have been studied. The development of the zero swirl case is found to be consistent with that of a single-stream mixing layer developing from a tripped boundary layer. In particular, the consistency of the measured stress levels shows the accuracy of the measurement syste...
Article
This note discusses the interpretation of X-probe measurements obtained in the presence of significant velocities transverse to the plane of the wires. To measure the three mean velocity components, the probe was used in two planes which gave a redundant estimate of the component along the probe axis. A correction of the measured mean velocities fo...
Article
Full-text available
A simple approximate criterion based on inlet conditions is proposed for the onset of recirculation in an expanding, swirling flow. It is compared with a criterion for vortex breakdown and one for recirculation in rapidly expanding swirling flows. Since recirculation is caused by the development of circumferential vorticity from the upstream axial...
Article
Measurements have been made in a swirling turbulent boundary layer affected by the angular momentum instability. The flow field seen by a rotating observer was obtained from a fixed hot-wire probe using the technique of phase-locked averaging. The instability is localized to the wall region of the boundary layer and there is some evidence that it h...
Article
Part 1 of this paper showed discrepancies between mean flow measurements and blade element theory predictions for flow behind a shrouded two-bladed wind turbine. To investigate these discrepancies further, phased-locked averaged measurements were made of the downstream flow. The theory of phase-locked averaging is given and the equation for the tur...
Article
This paper describes an investigation of blade element theory, which is commonly used to describe the flow through wind turbine blades. A two-bladed model turbine was shrouded by a constant-diameter pipe. The tip clearance was sufficiently small to minimise and localise the tip clearance losses. By passively heating the wake of one of the turbine s...
Article
This paper discusses the interpretation of X-probe measurements obtained in the wake of a model wind turbine using the technique of phase-locked averaging. To measure the three mean velocity components, the X-probe was used in two planes, giving a redundant estimate of the component along the probe axis. The correction of the measured mean velociti...
Article
Phase locked averaged measurements were obtained behind a model wind turbine to determine the velocity field relative the rotating blades. The accuracy of the phase locked results was found to be excellent. An equation for the turbine power as a function of the average, phase dependent, and turbulent components is derived. The phase dependent and t...