http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
A STABILIZED FINITE ELEMENT COMPUTATION OF FLOW AROUND OSCILLATING 2D BODIES
안형택(Hyung Taek Ahn),라술 라힐(Raheel Rasool) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.5
Numerical study of an oscillating body in incompressible fluid is performed. Stabilized finite element method comprising of Streamline-Upwind/Petrov-Galerkin (SUPG) and Pressure-Stabilizing/Petrov-Galerkin (PSPG) formulations of linear triangular elements was employed to solve 2D incompressible Navier-Stokes equations whereas the motion of the body was considered by incorporating the arbitrary Langrangian-Eulerian(ALE) formulation. An algebraic moving mesh strategy is utilized for obtaining body conforming mesh deformation at each time step. Two tests cases, namely motion of a circular cylinder and of an airfoil in incompressible flow were analyzed. The model is first validated against the stationary cases and then the capability to handle moving boundaries is demonstrated.
시뮬레이션 기반 수중 운동체의 유체력 미계수 결정 및 6자유도 운동해석
고광수(Gwangsoo Go),안형택(Hyung Taek Ahn),안진형(Jin-Hyeong Ahn) 한국해양공학회 2017 韓國海洋工學會誌 Vol.31 No.5
This paper introduces a simulation-based determination method for hydrodynamic derivatives and 6DOF (degrees-offreedom) motion analysis for an underwater vehicle. Hydrodynamic derivatives were derived from second-order modulus expansion and composed of the added mass, and linear and nonlinear damping coefficients. The added mass coefficients were analytically obtained using the potential theory. All of the linear and nonlinear damping coefficients were determined using CFD simulation, which were performed for various cases based on the actual operating condition. Then, the linear and nonlinear damping coefficients were determined by fitting the CFD results, which referred to 6DOF forces and moments acting on an underwater vehicle, with the least square method. To demonstrate the applicability of the current study, 6DOF simulations for three different scenarios (L-, U-, and S-turn) were carried out, and the results were validated on the basis of physical plausibility.
직교격자 기반 비압축성 솔버(ULSAN3D-Cart) 소개
고광수(Gwangsoo Go),안형택(Hyung Taek Ahn) 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.12
The Cartesian grid based-incompressible flow solver, namely ULSAN3D-Cart, is introduced in this paper. ULSAN3D-Cart involves two algorithm breakthroughs for Cartesian mesh-based flow simulations. The first is a novel efficient and reliable determination procedure of the signed distance function (SDF) based on an adaptive mesh refinement (AMR) strategy. In order to represent the body shape in Cartesian mesh, the SDF, which is 0 at the interface, positive at the exterior, negative at the interior, should be computed instead of grid generation. This new AMR-based algorithm proved to be an order of magnitude faster than a naive SDF computation on a uniform mesh. The second is an application of geometric multigrid on arbitrary complex domain. The geometric multigrid is known as the fastest solution algorithm for elliptic-type boundary value problems on regular domain. However, it is not clear whether geometric multigrid is the fastest on irregular domain or not. Based on current study, we confirmed that the optimal convergence, i.e. O(N) complexity, of multigrid was obtained on irregular domain as well. To demonstrate applicability of current solution algorithm, well-known benchmark problems were solved, and all results were validated by previous experimental and computational results.
STABILIZED FINITE ELEMENT METHOD FOR 3D VORTEX-INDUCED VIBRATION SIMULATION
Raheel Rasool(라힐 라술),Hyung Taek Ahn(안형택) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.11
Vortex-induced vibration of a circular cylinder is simulated within the finite element framework. A stabilized finite element method is employed for the fluid flow and beam structural element is used for the motion of a flexible cylinder. Various coupling strategies between the fluid and structural solvers are discussed. The viability of the approach is presented for the 3D incompressible flow around a flexible circular cylinder.
이은택(Euntaek LEE),권순은(SunEun Kwon),안형택(Hyung Taek AHN) 한국전산유체공학회 2014 한국전산유체공학회 학술대회논문집 Vol.2014 No.11
In Shipbuilding fields, there are strong demands for the CFD code which could simulate flow around a complex geometry, for example a marine propeller, perhaps the most complex shape among the parts of ship. In this paper, we discussed the way to simulate flow around a complex geometry with high-order accuracy. We solved the incompressible flow using artificial compressibility formulation. And High-order(>2nd order) solution is obtained by using a high-order solution reconstruction. We simulated various kind of simulations. And we showed the numerical results.