Examinando por Autor "Garcia, M.J."

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    Flow behaviour over a 2D body using the moving particle semi-implicit method with free surface stabilisation
    (Springer-Verlag France, 2017-08-01) Perez, C.A.; Garcia, M.J.; Barbosa Perez, Jaime L.; Orrego, Santiago; Quintero, Santiago; Mecánica Aplicada
    The Moving Particle Semi-implicit (MPS) method is a Lagrangian particle method based on the prediction-correction calculation of the velocity field and the Helmhotz-Hodge decomposition. Initially the predicted velocity is calculated with the viscous and external forces terms and then corrected by the gradient of the pressure which is obtained by the solution of the Poisson Pressure's equation. The MPS was developed for non-compressible bodies and it is adequate for free surface problems. However, when used to simulate fluid structure interaction problems, like ship resistance, the original formulation of the method can not accurately compute the pressure distribution over the bodies. This paper proposes a modified MPS method for modelling immerse bodies in an free surface flow. It was found that small variations in the source term of the Poisson Pressure's equation can destabilise simulations. Therefore, a reformulation of the Poisson pressure equation was developed. The results show that the proposed variation produced numerical stabilisation. The free surface particles behave in a good agreement with experimental observations. Also, although pressure fluctuations were still present, satisfactory results were obtained when comparing the drag coefficient with those reported values in the literature.
  • No hay miniatura disponible
    Ítem
    Flow behaviour over a 2D body using the moving particle semi-implicit method with free surface stabilisation
    (Springer-Verlag France, 2017-08-01) Perez, C.A.; Garcia, M.J.; Barbosa Perez, Jaime L.; Orrego, Santiago; Quintero, Santiago; Universidad EAFIT. Departamento de Ingeniería Mecánica; Estudios en Mantenimiento (GEMI)
    The Moving Particle Semi-implicit (MPS) method is a Lagrangian particle method based on the prediction-correction calculation of the velocity field and the Helmhotz-Hodge decomposition. Initially the predicted velocity is calculated with the viscous and external forces terms and then corrected by the gradient of the pressure which is obtained by the solution of the Poisson Pressure's equation. The MPS was developed for non-compressible bodies and it is adequate for free surface problems. However, when used to simulate fluid structure interaction problems, like ship resistance, the original formulation of the method can not accurately compute the pressure distribution over the bodies. This paper proposes a modified MPS method for modelling immerse bodies in an free surface flow. It was found that small variations in the source term of the Poisson Pressure's equation can destabilise simulations. Therefore, a reformulation of the Poisson pressure equation was developed. The results show that the proposed variation produced numerical stabilisation. The free surface particles behave in a good agreement with experimental observations. Also, although pressure fluctuations were still present, satisfactory results were obtained when comparing the drag coefficient with those reported values in the literature.
  • No hay miniatura disponible
    Ítem
    Flow behaviour over a 2D body using the moving particle semi-implicit method with free surface stabilisation
    (Springer-Verlag France, 2017-08-01) Perez, C.A.; Garcia, M.J.; Barbosa Perez, Jaime L.; Orrego, Santiago; Quintero, Santiago; Perez, C.A.; Garcia, M.J.; Barbosa Perez, Jaime L.; Orrego, Santiago; Quintero, Santiago; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecatrónica y Diseño de Máquinas
    The Moving Particle Semi-implicit (MPS) method is a Lagrangian particle method based on the prediction-correction calculation of the velocity field and the Helmhotz-Hodge decomposition. Initially the predicted velocity is calculated with the viscous and external forces terms and then corrected by the gradient of the pressure which is obtained by the solution of the Poisson Pressure's equation. The MPS was developed for non-compressible bodies and it is adequate for free surface problems. However, when used to simulate fluid structure interaction problems, like ship resistance, the original formulation of the method can not accurately compute the pressure distribution over the bodies. This paper proposes a modified MPS method for modelling immerse bodies in an free surface flow. It was found that small variations in the source term of the Poisson Pressure's equation can destabilise simulations. Therefore, a reformulation of the Poisson pressure equation was developed. The results show that the proposed variation produced numerical stabilisation. The free surface particles behave in a good agreement with experimental observations. Also, although pressure fluctuations were still present, satisfactory results were obtained when comparing the drag coefficient with those reported values in the literature.
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    Ítem
    Low altitude wind simulation over mount saint helens using NASA SRTM digital terrain model
    (2007-01-01) Garcia, M.J.; Boulanger, P.; Garcia, M.J.; Boulanger, P.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Mecánica Aplicada
    On February 11, 2000, the Shuttle Radar Topography Mission (SRTM) was launched into space as part of one of the pay load of the Shuttle Endeavor. Using a new radar sweeping technique most of the Earth's surfaces was digitized in 3D in approximately 10 days. SRTM acquired enough data during its mission to obtain a near-global high-resolution database of the Earth's topography. This paper describe how this revolutionary data set can be used to simulate anywhere around the Earth low altitude wind conditions for various atmospheric conditions. More specifically, we will describe the various processing steps necessary to convert this high-resolution terrain model provided by the SRTM database into a Computational Fluid Dynamic (CFD) volumetric mesh that is compatible with an open source CFD solver called OpenFOAM running in parallel on large West-Grid supercomputers. This work is the result of a new virtual wind-tunnel under development at the University of Alberta. In the paper, we present wind flow over the MountSaint Helens in the United States for a simple wind flow boundary condition. © 2006 IEEE.
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    ParaVoxel: A domain decomposition based fixed grid preprocessor
    (WORLD SCIENTIFIC PUBL CO PTE LTD, 2015-06-01) Garcia, M.J.; Duque, J.; Henao, M.; Boulanger, P.; Mecánica Aplicada
    In this paper, a parallel cartesian fixed grid mesh generator for structural and fluid dynamics problems is presented. The method uses the boundary representation of a body and produces a set of equal sized cells which are classified in three different types according to its location with respect to the body. Cells are inside, outside or intersecting the boundary of the body. This classification is made by knowing the number of nodes of a cell that are inside body. That process is accomplished very efficiently as the nodes can be classified in batch. Once boundary cells are identified, its geometry is approximated by the convex hull of the nodes inside the body and the intersection points of the boundary against the cell edges. This paper presents the basics of the Fixed Grid Meshing algorithm, followed by some domain decomposition modifications and the data structures required for its parallel implementation. A set of examples and a brief discussion on the possibility of applying this algorithm together with other approaches is presented. © 2015 World Scientific Publishing Company.