Examinando por Materia "Fluid structure interaction"

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    Ítem
    Acoustic displacement tetrahedra developed using the IET rules
    (PERGAMON-ELSEVIER SCIENCE LTD, 2010-09-01) Correa, S.; Militello, C.; Recuero, M.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)
    A four node, displacement based, acoustic element is developed. In order to avoid spurious rotational modes, a higher order stiffness is introduced. The higher order stiffness is developed from an incompatible strain field which computes element volume changes under nodal rotational displacements fields. The higher order strain satisfies the IET requirements, non affecting convergence. The higher order stiffness is modulated, element by element, with a factor. Thus, the displacement based formulation is capable of placing the spurious rotational modes over the range of physical compressional modes that can be accurately captured by the mesh. © 2010 Elsevier Ltd. All rights reserved.
  • No hay miniatura disponible
    Ítem
    Acoustic displacement tetrahedra developed using the IET rules
    (PERGAMON-ELSEVIER SCIENCE LTD, 2010-09-01) Correa, S.; Militello, C.; Recuero, M.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)
    A four node, displacement based, acoustic element is developed. In order to avoid spurious rotational modes, a higher order stiffness is introduced. The higher order stiffness is developed from an incompatible strain field which computes element volume changes under nodal rotational displacements fields. The higher order strain satisfies the IET requirements, non affecting convergence. The higher order stiffness is modulated, element by element, with a factor. Thus, the displacement based formulation is capable of placing the spurious rotational modes over the range of physical compressional modes that can be accurately captured by the mesh. © 2010 Elsevier Ltd. All rights reserved.
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    Ítem
    Hydraulic and rotor-dynamic interaction for performance evaluation on a Francis turbine
    (Springer-Verlag France, 2017-08-01) Garcia, M.; Laín, S.; Orrego, S.; Barbosa, J.; Quintero, B.; Garcia, M.; Laín, S.; Orrego, S.; Barbosa, J.; Quintero, B.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecatrónica y Diseño de Máquinas
    This paper proposes a new methodology to evaluate the technical state of a Francis turbine installed in a hydroelectric plant by coupling computational fluid dynamics (CFD) and rotor-dynamic analysis. CFD simulations predicted the hydraulic performance of the turbine. The obtained field forces, due to the fluid-structure interaction over the blades of the runner, were used as boundary condition in the shaft rotor-dynamic numerical model, which accurately predicted the dynamic behavior of the turbine's shaft. Both numerical models were validated with in situ experimental measurements. The CFD model was validated measuring the pressure fluctuations near the rotor-stator interaction area and the torque and radial force in the shaft using strain gages. The rotor-dynamic model was validated using accelerometers installed over the bearings supporting the shaft. Results from both numerical models were in agreement with experimental measurements and provided a full diagnose of the dynamic working condition of the principal systems of the turbine. Implementation of this methodology can be applied to further identify potential failure and improve future designs.
  • No hay miniatura disponible
    Ítem
    Hydraulic and rotor-dynamic interaction for performance evaluation on a Francis turbine
    (Springer-Verlag France, 2017-08-01) Garcia, M.; Laín, S.; Orrego, S.; Barbosa, J.; Quintero, B.; Mecánica Aplicada
    This paper proposes a new methodology to evaluate the technical state of a Francis turbine installed in a hydroelectric plant by coupling computational fluid dynamics (CFD) and rotor-dynamic analysis. CFD simulations predicted the hydraulic performance of the turbine. The obtained field forces, due to the fluid-structure interaction over the blades of the runner, were used as boundary condition in the shaft rotor-dynamic numerical model, which accurately predicted the dynamic behavior of the turbine's shaft. Both numerical models were validated with in situ experimental measurements. The CFD model was validated measuring the pressure fluctuations near the rotor-stator interaction area and the torque and radial force in the shaft using strain gages. The rotor-dynamic model was validated using accelerometers installed over the bearings supporting the shaft. Results from both numerical models were in agreement with experimental measurements and provided a full diagnose of the dynamic working condition of the principal systems of the turbine. Implementation of this methodology can be applied to further identify potential failure and improve future designs.
  • No hay miniatura disponible
    Ítem
    Hydraulic and rotor-dynamic interaction for performance evaluation on a Francis turbine
    (Springer-Verlag France, 2017-08-01) Garcia, M.; Laín, S.; Orrego, S.; Barbosa, J.; Quintero, B.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Estudios en Mantenimiento (GEMI)
    This paper proposes a new methodology to evaluate the technical state of a Francis turbine installed in a hydroelectric plant by coupling computational fluid dynamics (CFD) and rotor-dynamic analysis. CFD simulations predicted the hydraulic performance of the turbine. The obtained field forces, due to the fluid-structure interaction over the blades of the runner, were used as boundary condition in the shaft rotor-dynamic numerical model, which accurately predicted the dynamic behavior of the turbine's shaft. Both numerical models were validated with in situ experimental measurements. The CFD model was validated measuring the pressure fluctuations near the rotor-stator interaction area and the torque and radial force in the shaft using strain gages. The rotor-dynamic model was validated using accelerometers installed over the bearings supporting the shaft. Results from both numerical models were in agreement with experimental measurements and provided a full diagnose of the dynamic working condition of the principal systems of the turbine. Implementation of this methodology can be applied to further identify potential failure and improve future designs.
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    Ítem
    Non-invasive detection of vortex street cavitation
    (Pontificia Universidad Javeriana, 2017-01-01) Castro, A.; Botero, F.; Mecánica Aplicada
    Objective: This paper introduces a methodology for the non-intrusive detection of von Kármán vortex street cavitation. It is based on the cyclostationary analysis of the airborne noise radiated by the collapsing bubbles. Materials and methods: A hydrodynamic profile is mounted in the test section of a high-speed cavitation tunnel, and the phenomenon is reproduced under controlled conditions of flow and pressure. The angle of incidence is kept constant. Flow velocity is varied to regulate the vortex generation frequency, and the pressure is adjusted to control the cavitation onset. Highspeed photography is used to confirm the occurrence of cavitation in the core of the vortices. A laser vibrometer pointing to the upper surface of the profile validates the fluid-structure interaction due to the vortex shedding. A microphone is used to sense the sound produced by the phenomenon and transmitted to the environment. Results and discussion: The cyclic coherence showed uncoupled evidence of the periodic detachment of vortices and the presence or absence of cavitation in their cores, reaching values close to 0.7 for specific frequencies. Conclusion: A non-intrusive monitoring approach and a statistical indicator were implemented to allow the diagnosis of such phenomena. © 2017, Pontificia Universidad Javeriana. All rights reserved.