• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.112-115
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• 2009

In this paper, flow simulation algorithms for utilizing unstructured hybrid meshes are introduced. First, various types of meshes are introduced. Advantages and disadvantages of each type of meshes are discussed. Unstructured hybrid mesh approach, that is best suited for high speed viscous flow simulation, is presented. Lastly, various types of flow simulations using unstructured hybrid meshes are introduced.

• Journal of the Society of Naval Architects of Korea
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• v.54 no.2
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• pp.83-89
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• 2017

Numerical simulations of ship resistance have been performed to compare spatial characteristics of Courant number when using structured and unstructured meshes. When Euler scheme was used for time integration, the structured mesh provided a more efficient calculation because the calculation time interval was larger than that of unstructured mesh. The automatic generation of very small meshes in the unstructured mesh was mainly responsible for the limitation of calculation time interval. When local time stepping Euler scheme was applied, however, the ship resistance of unstructured mesh showed a rapid convergence while a slow convergence of ship resistance in structured mesh was caused by the small time interval in bulbous bow.

• 한국전산유체공학회:학술대회논문집
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• 2006.10a
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• pp.24-25
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• 2006

An unstructured mesh method has been developed for the simulation of steady and time-accurate flows around helicopter rotors. A dynamic and quasi-unsteady solution-adaptive mesh refinement technique was adopted for the enhancement of the solution accuracy in the local region of interest involving highly vortical flows. Applications were made to the 2-D blade-vortex interaction aerodynamics and the 3-D rotor blades in hover. The interaction between the rotor and the airframe in forward flight was investigated by introducing an overset mesh technique.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.27-32
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• 2008

In the present study, a conservative overset mesh technique has been developed on 2-D unstructured meshes. A new domain connection technique between independent mesh blocks was proposed to satisfy the conservation of mass, momentum, or energy in entire computational domain. The present technique was applied to several classical computational problems to validate the superiority of the conservative method to the non-conservative method.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.27-32
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• 2008

In the present study, a conservative overset mesh technique has been developed on 2-D unstructured meshes. A new domain connection technique between independent mesh blocks was proposed to satisfy the conservation of mass, momentum, or energy in entire computational domain. The present technique was applied to several classical computational problems to validate the superiority of the conservative method to the non-conservative method.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.55-55
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• 2003

• 한국전산유체공학회:학술대회논문집
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• 1998.11a
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• pp.42-47
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• 1998

The pressure-based methods are very popular in CFD because it requires less computer core memory compared to other coupled or density-based solvers. Currently structured-mesh methodology based on pressure-based algorithm is quite mature to apply to the practical problems. The unstructured mesh method needs much more computer memory than the structured-mesh method. However the pressure-based method utilizing the sequential approach does not require very large memory used for unstructured-mesh density-based solvers. The present study has developed the unstructured grid pressure-based method. Cell-centered finite volume method was selected due to robustness for imposing various boundary conditions and easy implementation of higher-order upwind scheme. The predictive capability of present method has validated against several benchmark problems.

• 대한방사선방어학회:학술대회논문집
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• 2011.11a
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• pp.174-175
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• 2011

• International Journal of Aeronautical and Space Sciences
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• v.10 no.1
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• pp.104-111
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• 2009

An unstructured overset mesh method has been developed for the simulation of unsteady flow fields around isolated rotors and rotor-fuselage configurations. The flow solver was parallelized for the efficient calculation of complicated flows requiring a large number of cells. A quasi-unsteady mesh adaptation technique was adopted to enhance the spatial accuracy of the solution and to better resolve the rotor wake. The method has been applied to calculate the flow fields around rotor-alone and rotor-fuselage configurations in forward flight. Validations were made by comparing the predicted results with those of measurements. It was demonstrated that the present method is efficient and robust for the prediction of unsteady time-accurate flow fields involving multiple bodies in relative motion.

• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.592-601
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• 2001

An automatic mesh generation scheme with unstructured quadrilateral elements on trimmed NURBS surfaces has been developed. In this paper NURBS surface geometries in the IGES format have been employed to represent geometric models. For unstructured mesh generation with quadrilateral elements, a domain decomposition algorithm employing loop operators has been modified. As for the surface meshing, an indirect 2D approach is proposed in which both quasi-expanded planes and projection planes are employed. Sampled meshes for complex models are presented to demonstrate the robustness of the algorithm.