The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform
Paul A. Brandner - One of the best experts on this subject based on the ideXlab platform.
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cloud cavitation behaviour on a Hydrofoil due to fluid structure interaction
Journal of Fluids Engineering-transactions of The Asme, 2019Co-Authors: Samuel Smith, Paul A. Brandner, B W Pearce, J A Venning, Dean R Giosio, Yin Lu YoungAbstract:Despite recent extensive research into fluid–structure interaction (FSI) of cavitating Hydrofoils, there remain insufficient experimental data to explain many of the observed phenomena. The cloud cavitation behavior around a Hydrofoil due to the effect of FSI is investigated, utilizing rigid and compliant three-dimensional (3D) Hydrofoils held in a cantilevered configuration in a cavitation tunnel. The Hydrofoils have identical undeformed geometry of tapered planform with a constant modified NACA0009 profile. The rigid model is made of stainless steel and the compliant model of a carbon and glass fiber-reinforced epoxy resin with the structural fibers aligned along the spanwise direction to avoid material bend-twist coupling. Tests were conducted at an incidence of 6 deg, a mean chord-based Reynolds number of 0.7 × 106 and cavitation number of 0.8. Force measurements were simultaneously acquired with high-speed imaging to enable correlation of forces with tip bending deformations and cavity physics. Hydrofoil compliance was seen to dampen the higher frequency force fluctuations while showing strong correlation between normal force and tip deflection. The 3D nature of the flow field was seen to cause complex cavitation behavior with two shedding modes observed on both models.
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experimental investigation of a Hydrofoil designed via hydrostructural optimization
Journal of Fluids and Structures, 2019Co-Authors: Nitin Garg, ANDREW W PHILLIPS, Paul A. Brandner, B W Pearce, Joaquim R R A Martins, Yin Lu YoungAbstract:Abstract In the last decade, there has been an increased interest in the use of multidisciplinary optimization techniques for the design of aerospace, maritime, and wind engineering systems. However, validation of numerically optimized results using experimental measurements has been scarce. In this paper, numerical predictions are compared with experimental measurements of the hydrodynamic forces, deformations, and cavitation performance for a baseline NACA 0009 Hydrofoil and an optimized Hydrofoil. Both Hydrofoils are made of solid aluminum, and are cantilevered at the root. One of the Hydrofoils is optimized using a high-fidelity hydrostructural solver combined with a gradient-based optimizer, as detailed by Garg et al. (2017). The numerical predictions agree well with experimental measurements for both the baseline NACA 0009 and the optimized Hydrofoils. For the optimized Hydrofoil, the mean differences between the predicted and measured values for mean lift, drag coefficient, and moment coefficients, are 2.9%, 5.1%, and 3.0%, respectively. For the non-dimensional tip bending deflection, the mean difference is 3.4%. Although the optimized Hydrofoil is significantly thicker to withstand higher loads than the baseline, it yields an overall measured increase in the lift-to-drag ratio of 29% for lift coefficients ranging from − 0 . 15 to 0.75 and exhibits significantly delayed cavitation inception compared to the baseline. The improvement in hydroelastic and cavitation performance is attributed to the changes in the distribution of camber, twist, thickness, and the leading edge radius of the optimized Hydrofoil. The results validate the analysis and optimization of the high-fidelity hydrostructural design optimization approach, and opens up new possibilities for the design of high-performance Hydrofoils, marine propellers, and turbines.
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cloud cavitation behaviour on a Hydrofoil due to fluid structure interaction
International Symposium on Transport Phenomena and Dynamics of Rotating Machinery (ISROMAC2017), 2017Co-Authors: Samuel Smith, Paul A. Brandner, B W Pearce, J A Venning, Dean R Giosio, Yin Lu YoungAbstract:Despite recent extensive research into fluid-structure interaction (FSI) of cavitating Hydrofoils there remains insufficient experimental data to explain many of these observed phenomena. The cloud cavitation behaviour around a Hydrofoil due to the effect of FSI is investigated utilizing rigid and compliant 3D Hydrofoils held in a cantilevered configuration in a cavitation tunnel. The Hydrofoils have identical undeformed geometry of tapered planform with constant NACA0009 section. The rigid model is made of stainless steel and the compliant model of carbon and glass fibre reinforced epoxy resin with the structural fibres aligned along the span-wise direction to avoid material bend-twist coupling. Tests were conducted at an incidence of 6°, a mean chord based Reynolds number of 0:7 _ 106, and cavitation number of 0.8. Force measurements were simultaneously acquired with high-speed imaging to enable correlation of forces with tip bending deformations and cavity physics. Hydrofoil compliance was seen to dampen the higher frequency force fluctuations while showing strong correlation between normal force and tip deflection. The 3D nature of the flow field was seen to cause complex cavitation behaviour with two shedding modes observed on both models.
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Numerical analysis of basic base-ventilated supercavitating Hydrofoil sections
Journal of Engineering for the Maritime Environment, 2015Co-Authors: Bryce W. Pearce, Paul A. BrandnerAbstract:A numerical analysis of the inviscid flow over base-ventilated intercepted Hydrofoils is presented. The low-order, non- linear boundary element formulation used is described along with the significant issues concerning the modelling of supercavities with this method. The use of transom-mounted interceptors is well established for the manoeuvring and trim control of high-speed vessels. The flow field over a forward-facing step at the trailing edge of a blunt-based Hydrofoil section, with consequent cavity detachment from the outer edge of the step, is similar to that of the transom-mounted interceptor operating at high speed with free surface detachment from the outer edge. Due to this similarity, the term ‘intercepted’ Hydrofoil is used to describe this arrangement. The results presented show that a number of geometric parameters, in particular thickness, leading-edge radius and trailing-edge slope, have a significant effect on the hydrody- namic performance of base-ventilated intercepted Hydrofoils.
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Experimental study of the steady fluid-structure interaction of flexible Hydrofoils
Journal of Fluids and Structures, 2014Co-Authors: Gustavo A. Zarruk, Paul A. Brandner, Bryce W. Pearce, ANDREW W PHILLIPSAbstract:This paper presents results from an experimental study of the hydrodynamic and hydroelastic performance of six different flexible Hydrofoils of similar geometry; four metal Hydrofoils of stainless steel (SS) and aluminum (AL), and two composite Hydrofoils of carbon-fiber reinforced plastic (CFRP). The two CFRP Hydrofoils had differing layups, one with fibers at 0° and the other at 30° relative to the spanwise axis of the Hydrofoil. All Hydrofoil models have the same unswept trapezoidal planform of aspect ratio 3.33. Two section profiles were chosen, a standard NACA0009 (Type I) and a modified NACA0009 (Type II) with a thicker trailing edge for improved manufacture of CFRP Hydrofoils. Hydrofoils were tested in a water tunnel mounted from a six-component force balance. Forces and deformations were measured at several chord-based Reynolds numbers up to Rec=1.0×106 and incidences beyond stall. Hysteresis, force fluctuations, and the natural frequency of the Hydrofoils in air and in water were also investigated. Pre-stall forces on the metal Hydrofoils were observed to be Reynolds number dependent for low values but became independent at 0.8×106 and greater. Forces on the CFRP Hydrofoils presented an increasing or decreasing lift slope for all Rec depending on the orientation of the carbon unidirectional layers. The change in loading pattern is due to the coupled bend-twist deformation experienced by the Hydrofoils under hydrodynamic loading. Forces and deflections in the Type I Hydrofoils were observed to be stable up to stall and non-dimensional tip deflections were found to be independent of incidence and Rec. Type II metal Hydrofoils had a mild Rec dependence, attributed to the blunt trailing edge, and Type II CFRP Hydrofoils had a stronger incidence and Rec dependence. The natural frequency under stall conditions of all but one of the CFRP Hydrofoils was in agreement with added mass and finite element analysis estimates. The disagreement was observed in the CFRP Hydrofoil with layers aligned at 30° and is attributed to the complex behavior of the carbon layers and to the coupled bend-twist deformation experienced under hydrodynamic loading of the Hydrofoil.
Yin Lu Young - One of the best experts on this subject based on the ideXlab platform.
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the hydroelastic response of a surface piercing Hydrofoil in multi phase flows part 1 passive hydroelasticity
Journal of Fluid Mechanics, 2019Co-Authors: Casey M Harwood, Mario Felli, M Falchi, Steven L Ceccio, Yin Lu YoungAbstract:Compliant lift-generating surfaces have widespread applications as marine propellers, Hydrofoils and control surfaces, and the fluid–structure interactions (FSI) of such systems have important effects upon their performance and stability. Multi-phase flows like cavitation and ventilation alter the hydrodynamic and hydroelastic behaviours of lifting surfaces in ways that are not yet completely understood. This paper describes experiments on one rigid and two flexible variants of a vertical surface-piercing Hydrofoil in wetted, ventilating and cavitating conditions. Tests were conducted in a towing tank and a free-surface cavitation channel. This work, which is Part 1 of a two-part series, examines the passive, or flow-induced, fluid–structure interactions of the Hydrofoils. Four characteristic flow regimes are described: fully wetted, partially ventilated, partially cavitating and fully ventilated. Hydroelastic coupling is shown to increase the hydrodynamic lift and yawing moments across all four flow regimes by augmenting the effective angle of attack. The effective angle of attack, which was derived using a beam model to account for the effect of spanwise twisting deflections, effectively collapses the hydrodynamic load coefficients for the three Hydrofoils. A generalized cavitation parameter, using the effective angle of attack, is used to collapse the lift and moment coefficients for all trials at a single immersed aspect ratio, smoothly bridging the four distinct flow regimes. None of the Hydrofoils approached the static divergence condition, which occurs when the hydrodynamic stiffness negates the structural stiffness, but theory and experiments both show that ventilation increases the divergence speed by reducing the hydrodynamic twisting moment about the elastic axis. Coherent vortex shedding from the blunt trailing edge of the Hydrofoil causes vortex-induced vibration at an approximately constant Strouhal number of 0.275 (based on the trailing edge thickness), and leads to amplified response at lock-in, when the vortex-shedding frequency approaches one of the resonant modal frequencies of the coupled fluid–structure system.
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cloud cavitation behaviour on a Hydrofoil due to fluid structure interaction
Journal of Fluids Engineering-transactions of The Asme, 2019Co-Authors: Samuel Smith, Paul A. Brandner, B W Pearce, J A Venning, Dean R Giosio, Yin Lu YoungAbstract:Despite recent extensive research into fluid–structure interaction (FSI) of cavitating Hydrofoils, there remain insufficient experimental data to explain many of the observed phenomena. The cloud cavitation behavior around a Hydrofoil due to the effect of FSI is investigated, utilizing rigid and compliant three-dimensional (3D) Hydrofoils held in a cantilevered configuration in a cavitation tunnel. The Hydrofoils have identical undeformed geometry of tapered planform with a constant modified NACA0009 profile. The rigid model is made of stainless steel and the compliant model of a carbon and glass fiber-reinforced epoxy resin with the structural fibers aligned along the spanwise direction to avoid material bend-twist coupling. Tests were conducted at an incidence of 6 deg, a mean chord-based Reynolds number of 0.7 × 106 and cavitation number of 0.8. Force measurements were simultaneously acquired with high-speed imaging to enable correlation of forces with tip bending deformations and cavity physics. Hydrofoil compliance was seen to dampen the higher frequency force fluctuations while showing strong correlation between normal force and tip deflection. The 3D nature of the flow field was seen to cause complex cavitation behavior with two shedding modes observed on both models.
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experimental investigation of a Hydrofoil designed via hydrostructural optimization
Journal of Fluids and Structures, 2019Co-Authors: Nitin Garg, ANDREW W PHILLIPS, Paul A. Brandner, B W Pearce, Joaquim R R A Martins, Yin Lu YoungAbstract:Abstract In the last decade, there has been an increased interest in the use of multidisciplinary optimization techniques for the design of aerospace, maritime, and wind engineering systems. However, validation of numerically optimized results using experimental measurements has been scarce. In this paper, numerical predictions are compared with experimental measurements of the hydrodynamic forces, deformations, and cavitation performance for a baseline NACA 0009 Hydrofoil and an optimized Hydrofoil. Both Hydrofoils are made of solid aluminum, and are cantilevered at the root. One of the Hydrofoils is optimized using a high-fidelity hydrostructural solver combined with a gradient-based optimizer, as detailed by Garg et al. (2017). The numerical predictions agree well with experimental measurements for both the baseline NACA 0009 and the optimized Hydrofoils. For the optimized Hydrofoil, the mean differences between the predicted and measured values for mean lift, drag coefficient, and moment coefficients, are 2.9%, 5.1%, and 3.0%, respectively. For the non-dimensional tip bending deflection, the mean difference is 3.4%. Although the optimized Hydrofoil is significantly thicker to withstand higher loads than the baseline, it yields an overall measured increase in the lift-to-drag ratio of 29% for lift coefficients ranging from − 0 . 15 to 0.75 and exhibits significantly delayed cavitation inception compared to the baseline. The improvement in hydroelastic and cavitation performance is attributed to the changes in the distribution of camber, twist, thickness, and the leading edge radius of the optimized Hydrofoil. The results validate the analysis and optimization of the high-fidelity hydrostructural design optimization approach, and opens up new possibilities for the design of high-performance Hydrofoils, marine propellers, and turbines.
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cloud cavitation behaviour on a Hydrofoil due to fluid structure interaction
International Symposium on Transport Phenomena and Dynamics of Rotating Machinery (ISROMAC2017), 2017Co-Authors: Samuel Smith, Paul A. Brandner, B W Pearce, J A Venning, Dean R Giosio, Yin Lu YoungAbstract:Despite recent extensive research into fluid-structure interaction (FSI) of cavitating Hydrofoils there remains insufficient experimental data to explain many of these observed phenomena. The cloud cavitation behaviour around a Hydrofoil due to the effect of FSI is investigated utilizing rigid and compliant 3D Hydrofoils held in a cantilevered configuration in a cavitation tunnel. The Hydrofoils have identical undeformed geometry of tapered planform with constant NACA0009 section. The rigid model is made of stainless steel and the compliant model of carbon and glass fibre reinforced epoxy resin with the structural fibres aligned along the span-wise direction to avoid material bend-twist coupling. Tests were conducted at an incidence of 6°, a mean chord based Reynolds number of 0:7 _ 106, and cavitation number of 0.8. Force measurements were simultaneously acquired with high-speed imaging to enable correlation of forces with tip bending deformations and cavity physics. Hydrofoil compliance was seen to dampen the higher frequency force fluctuations while showing strong correlation between normal force and tip deflection. The 3D nature of the flow field was seen to cause complex cavitation behaviour with two shedding modes observed on both models.
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high fidelity multipoint hydrostructural optimization of a 3 d Hydrofoil
Journal of Fluids and Structures, 2017Co-Authors: Nitin Garg, Joaquim R R A Martins, Gaetan K W Kenway, Yin Lu YoungAbstract:Abstract The design optimization of flexible Hydrofoils and propellers requires coupled hydrodynamic and structural analysis to achieve truly optimal, physically realizable, and structurally sound designs. To address this need, we develop an efficient high-fidelity hydrostructural design optimization approach that can handle large numbers of design variables, multiple design points, as well as design constraints on cavitation, maximum von Mises stress, and manufacturing tolerances. The hydrostructural solver couples a 3-D nearly incompressible Reynolds-averaged Navier–Stokes solver with a 3-D structural finite-element solver. We validate the solver by comparing the hydrodynamic load coefficients and tip bending deformations of a cantilevered aluminum alloy Hydrofoil with a NACA 0009 cross section and a trapezoidal planform. We use a coupled adjoint approach for efficient computation of the performance and constraint function derivatives with respect to 210 shape design variables. A single-point hydrostructural optimization of the NACA 0009 baseline Hydrofoil yields a 12.4% increase in lift-to-drag ratio, a 2.5% reduction in mass, and a 45% increase in the cavitation inception speed. However, the performance of the single-point optimized Hydrofoil is found to be worse than the baseline at off-design conditions. On the other hand, a multipoint optimization yields improved performance over the entire range of expected operating conditions with a weighted average increase in lift-to-drag ratio of 8.5%, and an increased cavitation inception speed of 38%. We compare the hydrostructural optimal result to an equivalent hydrodynamic-only optimization, and we show that only the hydrostructural optimized design satisfies the stress constraint up to the highest expected loading condition, highlighting the need for coupled hydrostructural optimization. The proposed approach enables multipoint optimization of hydrodynamic performance for Hydrofoils and marine propulsors with respect to detailed shape while enforcing design constraints. This constitutes a powerful new tool for improving existing designs, and exploring new concepts.
ANDREW W PHILLIPS - One of the best experts on this subject based on the ideXlab platform.
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experimental investigation of a Hydrofoil designed via hydrostructural optimization
Journal of Fluids and Structures, 2019Co-Authors: Nitin Garg, ANDREW W PHILLIPS, Paul A. Brandner, B W Pearce, Joaquim R R A Martins, Yin Lu YoungAbstract:Abstract In the last decade, there has been an increased interest in the use of multidisciplinary optimization techniques for the design of aerospace, maritime, and wind engineering systems. However, validation of numerically optimized results using experimental measurements has been scarce. In this paper, numerical predictions are compared with experimental measurements of the hydrodynamic forces, deformations, and cavitation performance for a baseline NACA 0009 Hydrofoil and an optimized Hydrofoil. Both Hydrofoils are made of solid aluminum, and are cantilevered at the root. One of the Hydrofoils is optimized using a high-fidelity hydrostructural solver combined with a gradient-based optimizer, as detailed by Garg et al. (2017). The numerical predictions agree well with experimental measurements for both the baseline NACA 0009 and the optimized Hydrofoils. For the optimized Hydrofoil, the mean differences between the predicted and measured values for mean lift, drag coefficient, and moment coefficients, are 2.9%, 5.1%, and 3.0%, respectively. For the non-dimensional tip bending deflection, the mean difference is 3.4%. Although the optimized Hydrofoil is significantly thicker to withstand higher loads than the baseline, it yields an overall measured increase in the lift-to-drag ratio of 29% for lift coefficients ranging from − 0 . 15 to 0.75 and exhibits significantly delayed cavitation inception compared to the baseline. The improvement in hydroelastic and cavitation performance is attributed to the changes in the distribution of camber, twist, thickness, and the leading edge radius of the optimized Hydrofoil. The results validate the analysis and optimization of the high-fidelity hydrostructural design optimization approach, and opens up new possibilities for the design of high-performance Hydrofoils, marine propellers, and turbines.
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Structural strength and laminate optimization of self-twisting composite Hydrofoils using a Genetic Algorithm
Composite Structures, 2017Co-Authors: Manudha T. Herath, ANDREW W PHILLIPS, B. Gangadhara Prusty, Nigel JohnAbstract:This paper presents a novel optimisation scheme using a Genetic Algorithm (GA) to produce a shape-adaptable composite Hydrofoil. Importantly the scheme included additional constraints that ensure that the Hydrofoils produced were able to be manufactured and have sufficient structural integrity to allow hydrodynamic testing in a cavitation tunnel. Hydrofoils optimised by this scheme were then manufactured using a closed mould Resin Transfer Moulding (RTM) process. Experimental modal analysis (EMA) as well as static cantilever load tests was then performed on the Hydrofoils to characterise their mechanical response. The EMA results showed that the Hydrofoils could be produced with excellent reproducibility with differences in natural frequencies in the order of 1%. The static cantilever results showed the predicted shape change occurred under load and that the Hydrofoils had sufficient strength to permit hydrodynamic testing. The results obtained were also used to validate the Finite Element Analysis (FEA) approached used to predict the Hydrofoils structural response.
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Experimental study of the steady fluid-structure interaction of flexible Hydrofoils
Journal of Fluids and Structures, 2014Co-Authors: Gustavo A. Zarruk, Paul A. Brandner, Bryce W. Pearce, ANDREW W PHILLIPSAbstract:This paper presents results from an experimental study of the hydrodynamic and hydroelastic performance of six different flexible Hydrofoils of similar geometry; four metal Hydrofoils of stainless steel (SS) and aluminum (AL), and two composite Hydrofoils of carbon-fiber reinforced plastic (CFRP). The two CFRP Hydrofoils had differing layups, one with fibers at 0° and the other at 30° relative to the spanwise axis of the Hydrofoil. All Hydrofoil models have the same unswept trapezoidal planform of aspect ratio 3.33. Two section profiles were chosen, a standard NACA0009 (Type I) and a modified NACA0009 (Type II) with a thicker trailing edge for improved manufacture of CFRP Hydrofoils. Hydrofoils were tested in a water tunnel mounted from a six-component force balance. Forces and deformations were measured at several chord-based Reynolds numbers up to Rec=1.0×106 and incidences beyond stall. Hysteresis, force fluctuations, and the natural frequency of the Hydrofoils in air and in water were also investigated. Pre-stall forces on the metal Hydrofoils were observed to be Reynolds number dependent for low values but became independent at 0.8×106 and greater. Forces on the CFRP Hydrofoils presented an increasing or decreasing lift slope for all Rec depending on the orientation of the carbon unidirectional layers. The change in loading pattern is due to the coupled bend-twist deformation experienced by the Hydrofoils under hydrodynamic loading. Forces and deflections in the Type I Hydrofoils were observed to be stable up to stall and non-dimensional tip deflections were found to be independent of incidence and Rec. Type II metal Hydrofoils had a mild Rec dependence, attributed to the blunt trailing edge, and Type II CFRP Hydrofoils had a stronger incidence and Rec dependence. The natural frequency under stall conditions of all but one of the CFRP Hydrofoils was in agreement with added mass and finite element analysis estimates. The disagreement was observed in the CFRP Hydrofoil with layers aligned at 30° and is attributed to the complex behavior of the carbon layers and to the coupled bend-twist deformation experienced under hydrodynamic loading of the Hydrofoil.
Bryce W. Pearce - One of the best experts on this subject based on the ideXlab platform.
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Numerical analysis of basic base-ventilated supercavitating Hydrofoil sections
Journal of Engineering for the Maritime Environment, 2015Co-Authors: Bryce W. Pearce, Paul A. BrandnerAbstract:A numerical analysis of the inviscid flow over base-ventilated intercepted Hydrofoils is presented. The low-order, non- linear boundary element formulation used is described along with the significant issues concerning the modelling of supercavities with this method. The use of transom-mounted interceptors is well established for the manoeuvring and trim control of high-speed vessels. The flow field over a forward-facing step at the trailing edge of a blunt-based Hydrofoil section, with consequent cavity detachment from the outer edge of the step, is similar to that of the transom-mounted interceptor operating at high speed with free surface detachment from the outer edge. Due to this similarity, the term ‘intercepted’ Hydrofoil is used to describe this arrangement. The results presented show that a number of geometric parameters, in particular thickness, leading-edge radius and trailing-edge slope, have a significant effect on the hydrody- namic performance of base-ventilated intercepted Hydrofoils.
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Experimental study of the steady fluid-structure interaction of flexible Hydrofoils
Journal of Fluids and Structures, 2014Co-Authors: Gustavo A. Zarruk, Paul A. Brandner, Bryce W. Pearce, ANDREW W PHILLIPSAbstract:This paper presents results from an experimental study of the hydrodynamic and hydroelastic performance of six different flexible Hydrofoils of similar geometry; four metal Hydrofoils of stainless steel (SS) and aluminum (AL), and two composite Hydrofoils of carbon-fiber reinforced plastic (CFRP). The two CFRP Hydrofoils had differing layups, one with fibers at 0° and the other at 30° relative to the spanwise axis of the Hydrofoil. All Hydrofoil models have the same unswept trapezoidal planform of aspect ratio 3.33. Two section profiles were chosen, a standard NACA0009 (Type I) and a modified NACA0009 (Type II) with a thicker trailing edge for improved manufacture of CFRP Hydrofoils. Hydrofoils were tested in a water tunnel mounted from a six-component force balance. Forces and deformations were measured at several chord-based Reynolds numbers up to Rec=1.0×106 and incidences beyond stall. Hysteresis, force fluctuations, and the natural frequency of the Hydrofoils in air and in water were also investigated. Pre-stall forces on the metal Hydrofoils were observed to be Reynolds number dependent for low values but became independent at 0.8×106 and greater. Forces on the CFRP Hydrofoils presented an increasing or decreasing lift slope for all Rec depending on the orientation of the carbon unidirectional layers. The change in loading pattern is due to the coupled bend-twist deformation experienced by the Hydrofoils under hydrodynamic loading. Forces and deflections in the Type I Hydrofoils were observed to be stable up to stall and non-dimensional tip deflections were found to be independent of incidence and Rec. Type II metal Hydrofoils had a mild Rec dependence, attributed to the blunt trailing edge, and Type II CFRP Hydrofoils had a stronger incidence and Rec dependence. The natural frequency under stall conditions of all but one of the CFRP Hydrofoils was in agreement with added mass and finite element analysis estimates. The disagreement was observed in the CFRP Hydrofoil with layers aligned at 30° and is attributed to the complex behavior of the carbon layers and to the coupled bend-twist deformation experienced under hydrodynamic loading of the Hydrofoil.
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Experimental Modelling of Steady Hydrofoil Fluid-Structure Interaction
18th Australasian Fluid Mechanics Conference, 2012Co-Authors: Paul A. Brandner, Bryce W. PearceAbstract:Static hydroelastic behaviour of two geometrically identical flexible metal Hydrofoils of Aluminium and Stainless Steel are investigated in a water tunnel. The Hydrofoils are of unswept trapezoidal planform, aspect ratio 3.33, NACA0009 section and were oriented vertically in the water tunnel mounted on a force balance through the test section ceiling. Forces and deflections were measured at several chord-based Reynolds numbers up to 106 and incidences beyond stall. Hysteresis and the effect of test section ceiling boundary layer thickness were investigated. Pre- stall forces where observed to be Reynolds number dependent for low values but became independent at 0.8×106 and greater. Tip deflections up to 4.5% of span were measured for the Alu- minium Hydrofoil. Forces and deflections were observed to be stable up to stall. Non-dimensional tip deflections of both hy- drofoils were found to be independent of incidence. Forces for both Hydrofoils compare closely for all incidences andReynolds numbers tested, within uncertainties, showing these to be inde- pendent of deformation.
Y-d Choi - One of the best experts on this subject based on the ideXlab platform.
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Shape design and numerical analysis on a 1MW tidal current turbine for the south-western coast of Korea
Renewable Energy, 2014Co-Authors: P.m. Singh, Y-d ChoiAbstract:The study concentrates on the shape design and numerical analysis of a 1MW horizontal axis tidal current turbine (HATCT), which can be applied near the southwest regions of Korea. On the basis of actual tidal current conditions of south-western region of Korea, configuration design of 1MW class turbine rotor blade is carried out by blade element momentum theory (BEMT). The hydrodynamic performance including the lift and drag forces, is conducted with the variation of the angle of attack using an open source code of X-Foil. The optimized blade geometry is used for Computational Fluid Dynamics (CFD) analysis with hexahedral numerical grids. This study focuses on developing a new Hydrofoil and designing a blade with relatively shorter chord length in contrast to a typical TCT blade. Therefore, after a thorough study of two common Hydrofoils, (S814 and DU-91-W2-250, which show good performance for rough conditions), a new Hydrofoil, MNU26, is developed. The new Hydrofoil has a 26% thickness that can be applied throughout the blade length, giving good structural strength. Power coefficient, pressure and velocity distributions are investigated according to Tip Speed Ratio by CFD analysis. As cavitation analysis is also an important part of the study, it is investigated for all the three Hydrofoils. Due to the shorter chord length of the new turbine blade in contrast to a typical TCT blade design, a Fluid Structure Interaction (FSI) analysis is also done. Concrete conclusions have been made after comparing the three Hydrofoils, considering their performance, efficiency, occurrence of cavitation and structural feasibility. © 2014 Elsevier Ltd.
