Publications
137 results found
Murua J, Palacios R, Peiro J, 2010, Camber effects in the dynamic aeroelasticity of compliant airfoils, International Forum of Aeroelasticity and Structural Dynamics, Seattle, Washington, USA, Publisher: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD, Pages: 527-543
This paper numerically investigates the effect of chordwise flexibility on the dynamic stability of compliant airfoils. A classical two-dimensional aeroelastic model is expanded with an additional degree of freedom to capture time-varying camber deformations, defined by a parabolic bending profile of the mean aerodynamic chord. Aerodynamic forces are obtained from unsteady thin airfoil theory and the corresponding compliant-airfoil inertia and stiffness from finite-element analysis. V g and state-space stability methods have been implemented in order to compute flutter speeds. The study looks at physical realizations with an increasing number of degrees of freedom, starting with a camber-alone system. It is shown that single camber leads to flutter, which occurs at a constant reduced frequency and is due to the lock in between the shed wake and the camber motion. The different combinations of camber deformations with pitch and plunge motions are also studied, including parametric analyses of their aeroelastic stability characteristics. A number of situations are identified in which the flutter boundary of the compliant airfoil exhibits a significant dip with respect to the rigid airfoil models. These results can be used as a first estimation of the aeroelastic stability boundaries of membrane-wing micro air vehicles. (C) 2010 Elsevier Ltd. All rights reserved.
Radaelli AG, Peiró J, 2010, On the segmentation of vascular geometries from medical images, International Journal Numerical Methods Bioengineering, Vol: 26, Pages: 3-34
Alastruey J, Nagel SR, Nier BA, et al., 2009, Modelling pulse wave propagation in the rabbit systemic circulation to assess the effects of altered nitric oxide synthesis, JOURNAL OF BIOMECHANICS, Vol: 42, Pages: 2116-2123, ISSN: 0021-9290
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- Citations: 22
Alastruey J, Parker KH, Peiro J, et al., 2009, Analysing the pattern of pulse waves in arterial networks: a time-domain study, JOURNAL OF ENGINEERING MATHEMATICS, Vol: 64, Pages: 331-351, ISSN: 0022-0833
Whelan JI, Graham JMR, Peiro J, 2009, A free-surface and blockage correction for tidal turbines, JOURNAL OF FLUID MECHANICS, Vol: 624, Pages: 281-291, ISSN: 0022-1120
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- Citations: 166
Endruweit A, Matthys KS, Peiro J, et al., 2009, Effect of differential compression on in-plane permeability tensor of heterogeneous multi-layer carbon fibre preforms, PLASTICS RUBBER AND COMPOSITES, Vol: 38, Pages: 1-9, ISSN: 1465-8011
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- Citations: 6
Arimon JA, Balossino R, D'Angelo C, et al., 2009, Applications and test cases, CARDIOVASCULAR MATHEMATICS: MODELING AND SIMULATION OF THE CIRCULATORY SYSTEM, Editors: Formaggia, Quarteroni, Veneziani, Publisher: SPRINGER, Pages: 447-475, ISBN: 978-88-470-1151-9
Peiro J, Veneziani A, 2009, Reduced models of the cardiovascular system, CARDIOVASCULAR MATHEMATICS: MODELING AND SIMULATION OF THE CIRCULATORY SYSTEM, Editors: Formaggia, Quarteroni, Veneziani, Publisher: SPRINGER, Pages: 347-394, ISBN: 978-88-470-1151-9
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- Citations: 31
Antiga L, Peiro J, Steinman DA, 2009, From image data to computational domains, CARDIOVASCULAR MATHEMATICS: MODELING AND SIMULATION OF THE CIRCULATORY SYSTEM, Editors: Formaggia, Quarteroni, Veneziani, Publisher: SPRINGER, Pages: 123-175, ISBN: 978-88-470-1151-9
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- Citations: 10
Peiro J, Sherwin SJ, Giordana S, 2008, Automatic reconstruction of a patient-specific high-order surface representation and its application to mesh generation for CFD calculations, MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING, Vol: 46, Pages: 1069-1083, ISSN: 0140-0118
Gambaruto AM, Peiro J, Doorly DJ, et al., 2008, Reconstruction of shape and its effect on flow in arterial conduits, INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Vol: 57, Pages: 495-517, ISSN: 0271-2091
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- Citations: 20
Galvanetto U, Peiro J, Chantharasenawong C, 2008, An assessment of some effects of the nonsmoothness of the Leishman-Beddoes dynamic stall model on the nonlinear dynamics of a typical aerofoil section, JOURNAL OF FLUIDS AND STRUCTURES, Vol: 24, Pages: 151-163, ISSN: 0889-9746
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- Citations: 20
Alastruey J, Parker KH, Peiro J, et al., 2008, Lumped parameter outflow models for 1-D blood flow simulations: Effect on pulse waves and parameter estimation, Commun. Comput. Phys., Vol: 4, Pages: 317-336
Several lumped parameter, or zero-dimensional (0-D), models of the micro-circulation are coupled in the time domain to the nonlinear, one-dimensional (1-D) equations of blood flow in large arteries. A linear analysis of the coupled system, together with in-vivo observations, shows that: (i) an inflow resistance that matches the characteristic impedance of the terminal arteries is required to avoid non-physiological wave reflections; (ii) periodic mean pressures and flow distributions in large arteries depend on arterial and peripheral resistances, but not on the compliances and inertias of the system, which only affect instantaneous pressure and flow waveforms; (iii) peripheral inertias have a minor effect on pulse waveforms under normal conditions; and (iv) the time constant of the diastolic pressure decay is the same in any 1-D model artery, if viscous dissipation can be neglected in these arteries, and it depends on all the peripheral compliances and resistances of the system. Following this analysis, we propose an algorithm to accurately estimate peripheral resistances and compliances from in-vivo data. This algorithm is verified against numerical data simulated using a 1-D model network of the 55 largest human arteries, in which the parameters of the peripheral windkessel outflow models are known a-priori. Pressure and flow waveforms in the aorta and the first generation of bifurcations are reproduced with relative root-mean-square errors smaller than 3%.
Alastruey J, Moore SM, Parker KH, et al., 2008, Reduced modelling of blood flow in the cerebral circulation: Coupling 1-D, 0-D and cerebral auto-regulation models, Int. J. Numer. Meth. Fluids, Vol: 56, Pages: 1061-1067
Galvanetto U, Peiro J, Chantharasenawong C, 2007, Remarks on the nonlinear dynamics of a typical aerofoil section in dynamic stall, AERONAUTICAL JOURNAL, Vol: 111, Pages: 731-739, ISSN: 0001-9240
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- Citations: 6
Peiro J, Formaggia L, Gazzola M, et al., 2007, Shape reconstruction from medical images and quality mesh generation via implicit surfaces, 13th International Conference on Finite Elements for Flow Problems, Publisher: WILEY, Pages: 1339-1360, ISSN: 0271-2091
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- Citations: 16
Alastruey J, Parker KH, Peiro J, et al., 2007, Modelling the circle of Willis to assess the effects of anatomical variations and occlusions on cerebral flows, JOURNAL OF BIOMECHANICS, Vol: 40, Pages: 1794-1805, ISSN: 0021-9290
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- Citations: 298
Matthys KS, Alastruey J, Peiro J, et al., 2007, Pulse wave propagation in a model human arterial network: Assessment of 1-D numerical simulations against in vitro measurements, J. Biomech., Vol: 40, Pages: 3476-3486
A numerical model based on the nonlinear, one-dimensional (1-D) equations of pressure and flow wave propagation in conduit arteries is tested against a well-defined experimental 1:1 replica of the human arterial tree. The tree consists of 37 silicone branches representing the largest central systemic arteries in the human, including the aorta, carotid arteries and arteries that perfuse the upper and lower limbs and the main abdominal organs. The set-up is mounted horizontally and connected to a pulsatile pump delivering a periodic output similar to the aortic flow. Terminal branches end in simple resistance models, consisting of stiff capillary tubes leading to an overflow reservoir that reflects a constant venous pressure. The parameters required by the numerical algorithm are directly measured in the \emph{in-vitro} set-up and no data fitting is involved. Comparison of experimental and numerical pressure and flow waveforms shows the ability of the 1-D time-domain formulation to capture the main features of pulse wave propagation measured throughout the system test. As a consequence of the simple resistive boundary conditions used to reduce the uncertainty of the parameters involved in the simulation, the experimental set-up generates waveforms at terminal branches with additional non-physiological oscillations. The frequencies of these oscillations are well captured by the 1-D model, even though amplitudes are overestimated. Adding energy losses in bifurcations and including fluid inertia and compliance to the purely resistive terminal models does not reduce the underdamped effect, suggesting that wall visco-elasticity might play an important role in the experimental results. Nevertheless, average relative root-mean-square errors between simulations and experimental waveforms are smaller than 4% for pressure and 19% for the flow at all 70 locations studied.
Alastruey J, Parker KH, Peiró J, et al., 2006, Can the modified Allen's test always detect sufficient collateral flow in the hand? A computational study., Comput Methods Biomech Biomed Engin, Vol: 9, Pages: 353-361, ISSN: 1025-5842
Blood flow in the largest arteries of the arm up to the digital arteries is numerically modelled using the one-dimensional equations of pressure and flow wave propagation in compliant vessels. The model can be applied to different anatomies of arterial networks and can simulate compression of arteries, these allowing us to simulate the modified Allen's test (MAT) and to assess its suitability for the detection of sufficient collateral flow in the hand if radial blood supply is interrupted. The test measures blood flow in the superficial palmar arch before and during compression of the radial artery. The absence of reversal flow in the palmar arch with the compression indicates insufficient collateral flow and is referred to as a positive MAT. This study shows that small calibres of the superficial palmar arch and insufficient compression of the radial artery can lead to false-positive results. Measurement of the drop in digital systolic pressures with compression of the radial artery has proved to be a more sensitive test to predict the presence of sufficient ulnar collateral flow in networks with small calibres of the superficial palmar arch. However, this study also shows that digital pressure measurements can fail in detecting enough collateral flow if the radial artery is insufficiently compressed.
Sherwin SJ, Kirby RM, Peiró J, et al., 2006, On 2D elliptic discontinuous Galerkin methods, INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Vol: 65, Pages: 752-784, ISSN: 0029-5981
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- Citations: 31
Gambaruto AM, Radaelli A, Doorly DJ, et al., 2005, Sensitivity study on by-pass graft reconstruction with emphasis on flow solutions, Pages: 832-833
Giordana S, Sherwin SJ, Peiró J, et al., 2005, Local and global geometric influence on steady flow in distal anastomoses of peripheral bypass grafts, JOURNAL OF BIOMECHANICAL ENGINEERING-TRANSACTIONS OF THE ASME, Vol: 127, Pages: 1087-1098, ISSN: 0148-0731
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- Citations: 39
Giordana S, Sherwin SJ, Peiró J, et al., 2005, Automated classification of peripheral distal by-pass geometries reconstructed from medical data, JOURNAL OF BIOMECHANICS, Vol: 38, Pages: 47-62, ISSN: 0021-9290
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- Citations: 24
Sherwin SJ, Peiro J, 2005, Finite difference, finite element and finite volume methods for partial differential equations, Handbook of materials modeling, Editors: Yip, Yip, Berlin, Publisher: Springer, Pages: 1-30, ISBN: 9781402032875
Giordana S, Radaelli A, Peiro J, et al., 2004, Geometry reconstruction and CFD modeling of arterial flows, Proceedings ICFD conference on numerical methods for fluid dynamics, Oxford, England, 29 March - 1 April 2004
Sherwin SJ, Franke V, Peiró J, et al., 2003, One-dimensional modelling of a vascular network in space-time variables, JOURNAL OF ENGINEERING MATHEMATICS, Vol: 47, Pages: 217-250, ISSN: 0022-0833
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- Citations: 311
Sherwin SJ, Formaggia L, Peiró J, et al., 2003, Computational modelling of 1D blood flow with variable mechanical properties and its application to the simulation of wave propagation in the human arterial system, INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Vol: 43, Pages: 673-700, ISSN: 0271-2091
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- Citations: 215
Zienkiewicz OC, Taylor RL, Sherwin SJ, et al., 2003, On discontinuous Galerkin methods, INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Vol: 58, Pages: 1119-1148, ISSN: 0029-5981
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- Citations: 63
Jackson MJ, Bicknell CD, Zervas V, et al., 2003, Three-dimensional reconstruction of autologous vein bypass graft distal anastomoses imaged with magnetic resonance:: Clinical and research applications, JOURNAL OF VASCULAR SURGERY, Vol: 38, Pages: 621-625, ISSN: 0741-5214
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- Citations: 11
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