Hydrodynamic Considerations Research Articles

Higher-form symmetry and chiral transport in real-time Abelian lattice gauge theory

We study classical lattice simulations of theories of electrodynamics coupled to charged matter at finite temperature, interpreting them using the higher-form symmetry formulation of magnetohydrodynamics (MHD). We compute transport coefficients using classical Kubo formulas on the lattice and show that the properties of the simulated plasma are in complete agreement with the predictions from effective field theories. In particular, the higher-form formulation allows us to understand from hydrodynamic considerations the relaxation rate of axial charge in the chiral plasma observed in previous simulations. A key point is that the resistivity of the plasma – defined in terms of Kubo formulas for the electric field in the 1-form formulation of MHD – remains a well-defined and predictive quantity at strong electromagnetic coupling. However, the Kubo formulas used to define the conventional conductivity vanish at low frequencies due to electrodynamic fluctuations, and thus the concept of the conductivity of a gauged electric current must be interpreted with care.

Enhancing Marina Sustainability: Water Quality and Flushing Efficiency in Marinas

Coastal marinas are particularly susceptible to pollution due to their limited flushing capabilities and ineffective management practices. Therefore, it is necessary to implement measures that promote enhanced sustainability. This study aims to explore the intricate relationship between tidal flushing characteristics and water quality within marinas to foster sustainable development and management practices that mitigate environmental impacts. The research scrutinized seven marinas along the Kuwait coastline, each exhibiting unique hydrodynamic conditions and geometric configurations. Water quality indicators such as BOD, COD, DO, and SO42− were evaluated concerning each marina’s flushing efficiency through field assessments and hydrodynamic numerical modeling. An empirical formula was developed to predict and optimize flushing mechanisms, which provided critical insights into the design and management of marinas to enhance water quality. The study revealed significant disparities in water quality across the examined marinas as the hydrodynamic and geometric conditions differed. The empirical formula developed offers a novel approach to quantitatively assessing flushing efficiency, which is valuable for marina designers and managers, facilitating informed decisions, and promoting environmental sustainability. This study underscores the critical importance of integrating hydrodynamic and geometric considerations in the design and management of marinas to improve water quality and sustainability. It advocates for a multifaceted strategy that includes advanced design solutions, rigorous policy implementation, and active community engagement to safeguard coastal marine environments. The findings emphasize the need for comprehensive environmental management plans.

Flotation of copper-bearing shale at different pH values of solutions and sodium chloride concentrations

Flotation of copper-bearing shale in aqueous solutions of NaCl at their different pH values was investigated. The tests were carried out in a laboratory flotation machine. The pH range was between 5 and 10 while NaCl concentrations were 0.5M, 1.0M and 2.0M. It was observed that the flotation recovery of the copper shale was increasing with the increase of pH and concentration of the salt solution. On the basis of thermodynamic and hydrodynamic considerations it was postulated that the increasing surface tension was responsible for better shale flotation observed with increasing salt concentration. The observed improved shale flotation caused by increasing pH is most likely due to changes in the properties of the thin film between particle and bubble including mosaic structure of water on the surface of shale. It was shown that the zeta potential of shale particles, zeta potential of air bubbles, solution surface tension, and shale hydrophobicity were not responsible for the increasing with pH recoveries.

Hydrodynamic considerations for spring-driven autoinjector design

In recent years, significant progress has been made in the studies of the spring-driven autoinjector, leading to an improved understanding of this device and its interactions with tissue and therapeutic proteins. The development of simulation tools that have been validated against experiments has also enhanced the prediction of the performance of spring-driven autoinjectors. This paper aims to address critical hydrodynamic considerations that impact the design of spring-driven autoinjectors, with a specific emphasis on sloshing and cavitation. Additionally, we present a framework that integrates simulation tools to predict the performance of spring-driven autoinjectors and optimize their design. This work is valuable to the pharmaceutic industry, as it provides crucial insights into the development of spring-driven autoinjectors and therapeutic proteins. This work can also enhance the efficacy and safety of the delivery of therapeutic proteins, ultimately improving patient outcomes.

Hydrodynamic considerations for improving the design/evaluation of over-topped bridge decks during extreme floods

Flow over an Iranian bridge deck is studied under an actual extreme flood event happening similarly nowadays in many countries due to climate change. Rigorous transient fluid-structure interaction analyses using the realizable k-ε turbulence model and the VOF Method are conducted. Geotechnical and abutments damages are neglected. Water surface profiles, velocity vectors, and hydrodynamic coefficients are determined. Based on the latest hydrological regime, particularly in supercritical flows, the results are partially compared against the latest advanced design codes, to evaluate the performance of their hydrodynamic and hydraulic provisions in similar incidents. It was acknowledged that the flood loads recommended by the Federal Highway Administration (FHWA) are fairly acceptable, Eurocode-1 predicts them rather accurately but not in extreme cases, and the Australian Standard (AS-5100.2) is less effective due to over-estimation of the hydrodynamic loads. Instead, the latter offers comprehensive user-defined hydraulic conditions. Furthermore, upon gradual rise of the water level to thrice the deck height, bridge stability is found to be at risk due to highly turbulent states. It is recommended that due to such threats, re-evaluation of flood regime, as well as its distinct hydrodynamic properties have to be accounted for, when evaluating existing bridges or designing new ones.

HULLFORM & HYDRODYNAMIC CONSIDERATIONS IN THE DESIGN OF THE UK FUTURE AIRCRAFT CARRIER (CVF)

An overview is provided of the manner in which hydrodynamic and hullform-related design considerations were addressed in the development of the BAE SYSTEMS team’s design proposal for the UK Future Aircraft Carrier (CVF). It also outlines how broader design considerations such as aviation, survivability and supportability requirements influenced these aspects of the design. A summary is also provided of some of the more detailed requirements development, option assessment and performance evaluation work that has been undertaken. The aircraft carrier designs discussed in this paper correspond to the BAE SYSTEMS team’s final design submission as it stood in January 2003, at the time it was discontinued by the UK Ministry of Defence, in favour of the rival Thales / BMT team design that has since been developed into the UK Royal Navy’s new ‘Queen Elizabeth’ class aircraft carrier. This final BAE SYSTEMS design submission consisted of two distinct design variants - one configured to operate a CTOL-based air group, the other configured to accommodate a STOVL air group. Both variants were based on a common ‘core’ ship design. The discussion presented in this paper is applicable to both variants.

Hydrodynamic Considerations VI: Temporary Shunting for Intraventricular Hemorrhage: Observational Study of Two Treatment Variants

Abstract Introduction Patients who have external ventricular drainage (EVD) inserted are prone to many risks and complications. Intraventricular hemorrhage (IVH) is a frequent and life-threatening complication for spontaneous intracerebral hemorrhage (ICH) and results in an increased morbidity and mortality for those patients. An EVD insertion is a frequent surgical procedure for those with IVH. However, it is also known that IVH patients have a much higher rate of ventricular catheter occlusion. We hypothesize that blood clots have a predominant participation as a pathophysiological mechanism for EVD occlusion, and that a different and more appropriate catheter design might decrease the occlusion rate occurring during the utilization of EVDs on patients with IVH and, therefore, reduce implantation time. Methods The electronic data sheets of 30 patients with spontaneous IVH from March 2014 until April 2015 were evaluated. Two concepts in catheter design were evaluated: A group of 15 patients with a conventional type of catheter inserted was identified as Group C (conventional). A group of 15 patients with a new design of catheter inserted was identified as Group H (hemorrhagic). Both groups were compared regarding survival end parameters, outcomes, days spent in intensive care units (ICUs) and time spent with EVDs implanted. Results Hospitalization at the ICU was statistically significantly reduced for Group H compared with Group C. There was no significant difference among the hospitalization days between both groups. There was no statistical difference either for acute hydrocephalus or death rate. External ventricular drainage implantation days were significantly reduced for Group H related to Group C. Conclusion The results of the present study points to the fact that, although apparently the new catheter design did not change some secondary complications such as hydrocephalus and hospitalization rate, it seems that a better or specifically designed catheter for IVH purposes might lead to less ICU hospitalization days and EVD implantation days, two factors that have economic impact on healthcare due to the reduction of hospitalization costs and reduced incidence of related complications. The information obtained by this preliminary study should be grounded by a larger, more detailed and prospective evaluation; if these preliminary data are maintained, the new design should be considered for IVH associated EVDs insertions.

Influence of Particular Design Parameters of Radial Guide Vane Cascades on Their Hydraulic Performance at Variable Speed Operated Francis Turbines

The design of radial blade cascades, with the intent to become turbine guide vanes, lies in the basis of satisfying turbine runner needs for a particular turbine design point of interest. For conventional turbine operation, the hydrodynamic parameters in the pre-runner space can be relatively easily estimated. For variable speed turbine operation at the constant head, these parameters change in a way that cannot be easily predicted using conventional techniques. In this paper, the guide vanes, as crucial turbine sub-system which needs to perform efficient runner flow feeding for these operating ranges, are numerically tested in various geometrical shapes and configurations, to observe the cascades behaviour, in a way of estimating which cascade configuration satisfies certain hydrodynamic and efficiency considerations of the operating points of interest. The criteria which the guide vanes need to meet are based on hydrodynamic parameters and expansion of the turbine operating range.

Measuring Dimensions of Ship-generated Waves in Guadalquivir Estuary Banks (SW Spain): Hydrodynamic Considerations

Morales, J.A.; Sedrati, M.; Boulmirate, O.; Borrego, J., and Carro, B.M., 2020. Measuring dimensions of ship-generated waves in Guadalquivir Estuary banks (SW Spain): Hydrodynamic considerations. In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 568–572. Coconut Creek (Florida), ISSN 0749-0208.Estuaries have always been very important to communities, as they often represent the economic centers of many countries. The estuarine banks, as fetch-limited environments, might be highly affected by some anthropogenic actions. Ship-generated waves are starting to be the subject of several studies in order to understand their impact on coastal environments. These waves might be the leading factor to erosion in estuarine channel margins when traffic is frequent. Guadalquivir is one of the most important estuaries in Spain. It connects an important number of commercial ships to the port of Seville. Along the estuary, bank erosion is highly pronounced which is starting to worry both, landowners and ecologists, since a part of the estuarine channel crosses the marine sector of Donana natural park. Last years, port of Seville intended to dredge the channel to get the entrance of bigger ships to the port. Ecologists argue that the magnitude of the waves generated by the ships is proportional to the size of the ship. So, the entrance of bigger ships will increase the erosion along the margins. The aim of this paper, is to obtain preliminary data to verify the relevance of this theory through a hydrodynamic survey using wave gauges on the banks and an ADCP in the bottom of the channel to control the modification of waves and currents caused by the ships.

Hydrodynamic considerations and design concepts for optimal thermal compressors

Novel and highly compact design concepts for the desorber and rectifier components are presented to facilitate development of small capacity ammonia-water absorption systems for a wide range of applications. These designs enable thermodynamically optimal diabatic distillation and can be applied for direct-coupled waste heat recovery applications or for indirect heat source coupling. A hydrodynamic design methodology is developed and applied to address liquid–vapor countercurrent flow limitations. Feasibility of these designs is validated through air-liquid flow visualization experiments that simulate target flow patterns. The effects of geometric parameters and fluid properties are investigated to specify internal component features and dimensions. Parameters for coupled heat and mass transfer modeling of these designs are identified and quantified through high-speed video analysis. The results of this study guide the design and further development of highly compact and efficient desorption components for optimal thermal compressors.

Optimization of Chemical Processes by the Hydrodynamic Simulation Method (HSM)

We describe a hydrodynamic simulation method (HSM) that is based on hydrodynamic considerations in Batch and Semi Batch stirred reactor systems. The method combines hydrodynamic studies of the mixing procedure obtained from experiments in small and large scale stirred reactors together with process simulation by VisiMix software. We describe how this hydrodynamic simulation method can aid in process optimization and scale up. The use of the simulation method described in this article, will offer the user the possibility to achieve the best results during production stage, saving time and currency, and at the same time increasing the knowledge of the performed process. Several examples in the article demonstrate the benefits of the proposed method.

Hullform & Hydrodynamic Considerations in the Design of the UK Future Aircraft Carrier (CVF)

An overview is provided of the manner in which hydrodynamic and hullform-related design considerations were addressed in the development of the BAE SYSTEMS team’s design proposal for the UK Future Aircraft Carrier (CVF). It also outlines how broader design considerations such as aviation, survivability and supportability requirements influenced these aspects of the design. A summary is also provided of some of the more detailed requirements development, option assessment and performance evaluation work that has been undertaken. The aircraft carrier designs discussed in this paper correspond to the BAE SYSTEMS team’s final design submission as it stood in January 2003, at the time it was discontinued by the UK Ministry of Defence, in favour of the rival Thales / BMT team design that has since been developed into the UK Royal Navy’s new ‘Queen Elizabeth’ class aircraft carrier. This final BAE SYSTEMS design submission consisted of two distinct design variants - one configured to operate a CTOL-based air group, the other configured to accommodate a STOVL air group. Both variants were based on a common ‘core’ ship design. The discussion presented in this paper is applicable to both variants. This paper was originally written for presentation at the June 2003 Royal Institution of Naval Architects ‘Warships 2003 - Air Power at Sea’ Conference. However, it was withheld from publication at the request of the UK Ministry of Defence, due to sensitivity surrounding the UK Aircraft Carrier project at that time. Following re-appraisal in June 2016, the UK Ministry of Defence has now authorised publication of this paper in full. The paper is presented here in its original (2003) form, with Section 2 added to provide historical perspective (given the passage of time).

Hullform & Hydrodynamic Considerations in the Design of the UK Future Aircraft Carrier (CVF) - Discussion Paper

Discussion Paper.

Hydrodynamic Considerations in Near-Optimal Control of a Small Wave Energy Converter for Ocean Measurement Applications

AbstractThis paper investigates the use of wave energy to power long-term ocean sensing systems. The device examined here consists of an oceanographic buoy and a shallow-submerged reaction frame that may carry a science instrument. Power conversion is from the relative heave oscillation between the two bodies. The oscillation is controlled on a wave-by-wave basis using near-optimal feedforward control, which requires up-wave surface elevation measurement and deterministic prediction at the device location. This paper presents the dynamic formulation used to evaluate the near-optimal, wave-by-wave control forces in the time domain. Also examined are reaction-frame geometries for their impact on overall power capture through favorable hydrodynamic interactions. Performance is evaluated in a range of wave conditions (from most to least favorable for conversion) sampled over a year at a chosen site of deployment. It is found that control may be able to provide the required amounts of power to sustain instrument operation at the chosen site but also that energy storage options may be worth pursuing.<def-list>Nomenclature<def-item><term>αr</term><def>Maximum displacement allowed by the swept volume constraint</def></def-item><def-item><term>βr (ω)</term><def>Velocity constraint</def></def-item><def-item><term>η(x; iω)</term><def>Frequency-domain expression for wave surface elevation</def></def-item><def-item><term>η(x, t)</term><def>Time-domain wave surface elevation at point x and time t</def></def-item><def-item><term>ω</term><def>Angular frequency of wave/oscillation</def></def-item><def-item><term>āt(ω), āb(ω)</term><def>Added mass variations for the top and bottom bodies, respectively, inclusive of infinite-frequency parts</def></def-item><def-item><term>A</term><def>Incident wave amplitude</def></def-item><def-item><term>Ac(ω), bc(ω)</term><def>Added mass and radiation damping coefficients representing the frequency-dependent radiation coupling between the top and bottom bodies</def></def-item><def-item><term>bt(ω), bb(ω)</term><def>Radiation damping variations for the top and bottom bodies, respectively</def></def-item><def-item><term>cdt, cdb</term><def>Linearized, constant viscous damping coefficients for the top and bottom bodies, respectively</def></def-item><def-item><term>D</term><def>Constant damping load applied on the relative heave oscillation</def></def-item><def-item><term>D</term><def>Distance between the up-wave measurement point and the device centroid; xB ‐ xA</def></def-item><def-item><term>Fa(t)</term><def>Reactive control force applied by the power takeoff</def></def-item><def-item><term>Fe(iω)</term><def>Effective heave force</def></def-item><def-item><term>Fl(t)</term><def>Resistive control force applied by the power takeoff</def></def-item><def-item><term>Ffb(iω)</term><def>Exciting force coefficient of reaction frame</def></def-item><def-item><term>Fft, Ffb</term><def>Exciting forces on the top and bottom bodies, respectively</def></def-item><def-item><term>Fft (iω)</term><def>Exciting force coefficient of standard buoy</def></def-item><def-item><term>Frelative (iω)</term><def>Relative exciting force coefficient</def></def-item><def-item><term>Ftotal (iω)</term><def>Total exciting force coefficient</def></def-item><def-item><term>g</term><def>Acceleration of gravity</def></def-item><def-item><term>hl (t; d)</term><def>Impulse response function defining the deterministic propagation model for distance D</def></def-item><def-item><term>hs1(2)</term><def>Significant wave height for swell (wind) seas</def></def-item><def-item><term>k(ω)</term><def>Wave number; related to angular frequency ω through the dispersion relation</def></def-item><def-item><term>kt, kb</term><def>Stiffness constants determining the restoring forces on the top and bottom bodies, respectively</def></def-item><def-item><term>mt, mb</term><def>In-air masses of the top and bottom bodies, respectively</def></def-item><def-item><term>Pω</term><def>Average power absorbed over time t</def></def-item><def-item><term>Ri</term><def>Relative radiation damping coefficient</def></def-item><def-item><term>Ri(ω), ci(ω)</term><def>Equivalent hydrodynamic damping and reactance components “acting on” the relative oscillation between the two bodies</def></def-item><def-item><term>s</term><def>Geometric scale factor, defined as ratio of full-scale length dimension and model-scale length dimension</def></def-item><def-item><term>te1(2)</term><def>Energy period for swell (wind) seas</def></def-item><def-item><term>vr, xr</term><def>Relative heave velocity and displacement between the top and bottom bodies</def></def-item><def-item><term>vt, vb</term><def>Heave oscillation velocities of the top and bottom bodies, respectively</def></def-item><def-item><term>vro (iω)</term><def>Hydrodynamically optimum velocity</def></def-item><def-item><term>Zb</term><def>Complex impedance of the bottom body</def></def-item><def-item><term>Zc</term><def>Complex impedance representing radiation coupling between the top and bottom bodies</def></def-item><def-item><term>ZL</term><def>Complex impedance representing resistive and reactive loads</def></def-item><def-item><term>Zt</term><def>Complex impedance of the top body</def></def-item></def-list>

Hydro-aerodynamic mathematical model and multi-objective optimization of wing-in-ground effect craft in take-off

Hydro-aerodynamic mathematical model and multi-objective optimization of a popular wing-in-ground effect craft are presented in this research using a hydro-aerodynamic practical method and the genetic algorithm. The primary components of the wing-in-ground effect craft configuration include a compound wing, catamaran hull form and a power-augmented ram platform. The hydro-aerodynamic practical method with low computational time and high accuracy is performed by coupling hydrodynamic and aerodynamic considerations using the potential flow theory in ground effect and the semi-empirical equations proposed for high-speed marine vehicles. The trade-off between hydrodynamic and aerodynamic characteristics makes it difficult to simultaneously satisfy the design requirements of high hydro-aerodynamic performance. In this article, three goals—reduced hump resistance, increased compound wing lift-to-drag ratio and reduced take-off speed—are selected as the objective functions. The longitudinal position of center of gravity, position of outer wing with respect to main wing, power augmented ram platform angle to horizontal and flap angle are also adopted as design variables. Static height stability and the location of the center of gravity with respect to the aerodynamics centers are considered as constraints for the stable flight in ground effect. The optimal solutions of the multi-objective optimization were not unique, rather a set of non-dominated optima, called the Pareto sets, are obtained. As a result of the multi-objective optimization, 25 Pareto individuals are obtained that the naval architects can use in designing wing-in-ground crafts.

A molecular dynamics investigation of the influence of water structure on ion conduction through a carbon nanotube.

Molecular dynamics simulations are employed to investigate pressure-driven water and ion transport through a (9,9) carbon nanotube (CNT). We consider NaCl solutions modeled with both the TIP3P and TIP4P/2005 water models. Concentrations range from 0.25 to 2.8 mol l-1 and temperatures from 260 to 320 K are considered. We discuss the influences on flow rates of continuum hydrodynamic considerations and molecular structural effects. We show that the flow rate of water, sodium, and chloride ions through the CNT is strongly model dependent, consistent with earlier simulations of pure water conduction. To remove the effects of different water flow rates, and clearly expose the influence of other factors on ion flow, we calculate ion transport efficiencies. Ion transport efficiencies are much smaller for TIP4P/2005 solutions than for those using the TIP3P model. Particularly at lower temperatures, the ion transport efficiencies for the TIP4P/2005 model are small, despite the fact that the nanotube conducts water at a significant rate. We trace the origin of small ion transport efficiencies to the presence of ring-like water structures within the CNT. Such structures occur commonly for the TIP4P/2005 model, but less frequently for TIP3P. The water structure acts to reduce ion "solvation" within the CNT, posing an additional barrier to ion entry and transport. Our results demonstrate that increasing the water structure within the CNT by decreasing the temperature strongly inhibits ion conduction, while still permitting significant water transport.

Theoretical and computational fluid dynamics of an attached remora (Echeneis naucrates)

Remora fishes have a unique dorsal suction pad that allows them to form robust, reliable, and reversible attachment to a wide variety of host organisms and marine vessels. Although investigations of the suction pad have been performed, the primary force that remoras must resist, namely fluid drag, has received little attention. This work provides a theoretical estimate of the drag experienced by an attached remora using computational fluid dynamics informed by geometry obtained from micro-computed tomography. Here, simulated flows are compared to measured flow fields of a euthanized specimen in a flow tank. Additionally, the influence of the host’s boundary layer is investigated, and scaling relationships between remora features are inferred from the digitized geometry. The results suggest the drag on an attached remora is similar to that of a streamlined body, and is minimally influenced by the host’s viscous boundary layer. Consequently, this evidence does not support the hypothesis that remoras discriminate between attachment locations based on hydrodynamic considerations. Comparison of the simulated drag with experimental friction tests show that even at elevated swimming speeds it is unlikely that remoras are dislodged by drag alone, and furthermore that larger remoras may be more difficult to dislodge than smaller remoras indicating that they become more suited to attachment as they mature.

Modeling and Simulation of the Autocatalytic Kinetics of Haemoglobin SS Polymerization: Onset of Polymerization

We report a fresh and simpler approach to the modelling of the kinetics of the polymerization of Hb SS in sickle cell patients that couples the kinetics and the hydrodynamics of blood flow in mechanistic understanding of the process. The well-known two-step autocatalytic reaction scheme was used for the polymerization reaction with the assumption of simpler first-order reaction scheme for each stage. In addition, the forces acting on a particle in motion were also introduced to account for compelling settling of the red cells that lead to vessel occlusion (vaso-occlusion). A first attempt on the prediction of vessel blockage was made using this novel model. The time for the onset of the polymerization reaction was derived from hydrodynamic considerations and kinetics while the kinetic rate constants were obtained from the autocatalytic nature of the reaction. Experimental data for model validation were obtained from recruited SS patients and in vitro data of Hofrichter. Over 100 volunteers were recruited for participation in this work but less than 40% met the inclusion criteria. Participants were of age range 13 - 43 (with a mean of 26 ± 8 years) for SCD patients and 18 - 43 (with a mean of 28 ± 7 years) for control participants. Blood indices and Transcranial Doppler (TCD) test parameters of all participants were the principal parameters used for model validation. Constant k2/k1 ratios was obtained for individual in vivo/in vitro system. This ratio is unique for any individual, independent on protein sequence and also suggests the degree of expression of the symptoms of Sickle Cell Disease (SCD) with higher values reflecting greater propensity to pain crisis. Delay time, tD, was found to have an inverse relationship with the kinetic constant for the residual reaction, k1. Therefore, long delay times calculated, offer insight on why SCD patients are not in perpetual crises because enough time is provided the cells to escape microcirculation while keeping the residual reaction at the minimum. Sensitivity analysis was carried out to obviate the limitations encountered in the course of the work. Results showed the onset of occlusion to be most sensitive to the diameter of the blood vessel.

Design Parameters Analysis of Point Absorber WEC via an evolutionary-algorithm-based Dimensioning Tool

Wave energy conversion has an essential difference from other renewable energies since the dependence between the devices design and the energy resource is stronger. Dimensioning is therefore considered a key stage when a design project of Wave Energy Converters (WEC) is undertaken. Location, WEC concept, Power Take-Off (PTO) type, control strategy and hydrodynamic resonance considerations are some of the critical aspects to take into account to achieve a good performance. The paper proposes an automatic dimensioning methodology to be accomplished at the initial design project stages and the following elements are described to carry out the study: an optimization design algorithm, its objective functions and restrictions, a PTO model, as well as a procedure to evaluate the WEC energy production. After that, a parametric analysis is included considering different combinations of the key parameters previously introduced. A variety of study cases are analysed from the point of view of energy production for different design-parameters and all of them are compared with a reference case. Finally, a discussion is presented based on the results obtained, and some recommendations to face the WEC design stage are given.

Geometrical Shape Optimization of a Cavity Receiver Using Coupled Radiative and Hydrodynamic Modeling

Abstract By using a two-stage optimisation process we maximise the heat rate output of afour-parameter axisymmetric direct steam generation cavity receiver. The model includes radiative and hydrodynamic considerations. We show that a significant range of geometrical shapes show similar efficiencies while having different wall flux and temperature profiles.