FLOW AROUND A BEE, UNSTRUCTURED GRID GENERATION

K. Nakahashi 한국전산유체공학회 2003 한국전산유체공학회 학술대회논문집 Vol.2003 No.10

Regulation of Immune Responses by the Activating and Inhibitory Myeloid-Associate Immunoglobuline-Like Receptors (MAIR) (CD300)

Shibuya, Akira,Nakahashi-Oda, Chigusa,Tahara-Hanaoka, Satoko The Korean Association of Immunobiologists 2009 Immune Network Vol.9 No.2

Activating and inhibitory cell surface receptors play important roles in regulation of immune responses. Recent progress has demonstrated that many inhibitory receptors pair with activating, as well as inhibitory, isoforms, both of whose genes are located in small clusters on a chromosome. We and others identified paired activating and inhibitory immunoglobulin-like receptors, designated myeloid-associated immunoglobulin-like receptors (MAIR) (CD300). MAIR is a multigene family consisting of nine genes on a small segment of mouse chromosome 11. MAIR family receptors are preferentially expressed on myeloid cells, including macrophages, dendritic cells, granulocytes, and bone-marrow-derived cultured mast cells, and a subset of B cells and regulate activation of these cells. Thus, MAIR plays an important role in innate immunity mediated by myeloid cells.

Three-Dimensional Building-Cube Method for Inviscid Compressible Flow Computations

김래성,Kazuhiro Nakahashi,Zhe-Zhu Xu,Hong Xiao,류성기 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.13

In this study, the Building-Cube method (BCM) devised for calculating large-scale flows and getting rid of the grid dependencies of computational results is extended to perform 3D inviscid compressible fluid flow simulations. The proposed scheme divides a computational domain into a large number of cubes with different sizes, and each individual cube is a sub-flow field simulated with a Cartesian grid of uniform spacing and an equal number of cells and nodes. Through the proposed scheme, we determine the geometric size of individual cube by Adapting the flow characteristics and geometrical shapes using an adaptively refining Cartesian grid approaches. The uniform spacing and equal number of cells and nodes in the Cartesian grid of individual cubes ensure a good performance for parallel computations; large result data can be handled efficiently. Further, an algorithm to solve the inviscid flow equations on the Building-Cube mesh for three-dimensional (3D) geometries is presented. The validation and performance of the proposed 3D BCM are demonstrated through comparisons of the computed results with the experimental data for the ONERA M6 wing and ONERA M5 wing-fuselage configurations.

Adaptive Mesh Refinement Using Viscous Adjoint Method for Single- and Multi-Element Airfoil Analysis

Yamahara, Toru,Nakahashi, Kazuhiro,Kim, Hyoungjin The Korean Society for Aeronautical and Space Scie 2017 International Journal of Aeronautical and Space Sc Vol.18 No.4

An adjoint-based error estimation and mesh adaptation study is conducted for two-dimensional viscous flows on unstructured hybrid meshes. The error in an integral output functional of interest is estimated by a dot product of the residual vector and adjoint variable vector. Regions for the mesh to be adapted are selected based on the amount of local error at each nodal point. Triangular cells in the adaptive regions are refined by regular refinement, and quadrangular cells near viscous walls are bisected accordingly. The present procedure is applied to single-element airfoils such as the RAE2822 at a transonic regime and a diamond-shaped airfoil at a supersonic regime. Then the 30P30N multi-element airfoil at a low subsonic regime with a high incidence angle (${\alpha}=21deg.$) is analyzed. The same level of prediction accuracy for lift and drag is achieved with much less mesh points than the uniform mesh refinement approach. The detailed procedure of the adjoint-based mesh refinement for the multi-element airfoil case show that the basic flow features around the airfoil should be resolved so that the adjoint method can accurately estimate an output error.

Adaptive Mesh Refinement Using Viscous Adjoint Method for Single- and Multi-Element Airfoil Analysis

Toru Yamahara,Kazuhiro Nakahashi,김형진 한국항공우주학회 2017 International Journal of Aeronautical and Space Sc Vol.18 No.4

An adjoint-based error estimation and mesh adaptation study is conducted for two-dimensional viscous flows on unstructured hybrid meshes. The error in an integral output functional of interest is estimated by a dot product of the residual vector and adjoint variable vector. Regions for the mesh to be adapted are selected based on the amount of local error at each nodal point. Triangular cells in the adaptive regions are refined by regular refinement, and quadrangular cells near viscous walls are bisected accordingly. The present procedure is applied to single-element airfoils such as the RAE2822 at a transonic regime and a diamond-shaped airfoil at a supersonic regime. Then the 30P30N multi-element airfoil at a low subsonic regime with a high incidence angle (α=21deg.) is analyzed. The same level of prediction accuracy for lift and drag is achieved with much less mesh points than the uniform mesh refinement approach. The detailed procedure of the adjoint-based mesh refinement for the multi-element airfoil case show that the basic flow features around the airfoil should be resolved so that the adjoint method can accurately estimate an output error.

Regulation of Immune Responses by the Activating and Inhibitory Myeloid-Associate Immunoglobuline-Like Receptors (MAIR) (CD300)

Akira Shibuya,Chigusa Nakahashi-Oda,Satoko Tahara-Hanaoka 대한면역학회 2009 Immune Network Vol.9 No.2

Activating and inhibitory cell surface receptors play important roles in regulation of immune responses. Recent progress has demonstrated that many inhibitory receptors pair with activating, as well as inhibitory, isoforms, both of whose genes are located in small clusters on a chromosome. We and others identified paired activating and inhibitory immunoglobulin- like receptors, designated myeloid-associated immunoglobulin-like receptors (MAIR) (CD300). MAIR is a multigene family consisting of nine genes on a small segment of mouse chromosome 11. MAIR family receptors are preferentially expressed on myeloid cells, including macrophages, dendritic cells, granulocytes, and bone-marrow-derived cultured mast cells, and a subset of B cells and regulate activation of these cells. Thus, MAIR plays an important role in innate immunity mediated by myeloid cells. Activating and inhibitory cell surface receptors play important roles in regulation of immune responses. Recent progress has demonstrated that many inhibitory receptors pair with activating, as well as inhibitory, isoforms, both of whose genes are located in small clusters on a chromosome. We and others identified paired activating and inhibitory immunoglobulin- like receptors, designated myeloid-associated immunoglobulin-like receptors (MAIR) (CD300). MAIR is a multigene family consisting of nine genes on a small segment of mouse chromosome 11. MAIR family receptors are preferentially expressed on myeloid cells, including macrophages, dendritic cells, granulocytes, and bone-marrow-derived cultured mast cells, and a subset of B cells and regulate activation of these cells. Thus, MAIR plays an important role in innate immunity mediated by myeloid cells.

High-Density Mesh Flow Computations by Building-Cube Method

L. S. Kim,K. Nakahashi,H. K. Jeong,M. Y. Ha 대한기계학회 2007 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.21 No.8

With the conventional computational fluid dynamics (CFD) approaches like unstructured high-density mesh method, the problem about the solution dependencies on the grid and on the physical models isn't completely resolved. In this study, thus, a new approach named Building-Cube Method based on a Cartesian mesh is proposed using a high-density mesh in order to solve the problem of the current CFD approaches. In the present method, a flow field is divided into a number of cubes (squares in 2D) of various sizes. Each cube is a computational sub-domain with Cartesian mesh of equal spacing and equal number of nodes. The geometrical size of each cube is determined by adapting to geometry and flow features so as to cope with broadband characteristic lengths of the flow. Equal spacing and equal number of Cartesian mesh in each cube make it easy to parallelize the flow solver and to handle huge data output. The method is applied to several airfoils including NACA0012 and two-element airfoils at relatively low Reynolds number, RAE2822 airfoil with transition trip at high Reynolds number and a four-element airfoil at high Reynolds number. These results validate the capability of the present approach.

SUPERSONIC WING-NACELLE CONFIGURATION DESIGN USING AN UNSTRUCTURED ADJOINT METHOD

Kim Hyoung-Jin,Obayashi Shigeru,Nakahashi Kazuhiro Korea Society of Computational Fluids Engineering 2000 한국전산유체공학회지 Vol.5 No.3

3차원 Euler 방정식과 adjoint법을 이용한 공력설계코드를 개발하였으며, 이를 초음속수송기의 주날개 설계에 적용하였다. 표면형상의 변화를 위해 Hicks-Henne함수를 사용하였으며, 내부격자점의 수정을 위해 타원형방정식법을 이용하였다. 나셀의 수직이동과 관련되지 않은 설계변수에 대해서는 내부격자점의 이동을 무시함으로써 계산시간을 크게 단축할 수 있었다. 양력과 날개단면두께를 일정하게 유지하면서 항력을 최소화하도록 단면형상을 최적화하였으며, 성공적인 결과를 얻음으로써 본 설계시스템의 타당성 및 효율성을 확인하였다.

AERODYNAMIC OPTIMIZATION OF SUPERSONIC WING-NACELLE CONFIGURATION USING AN UNSTRUCTURED ADJOINT METHOD

Hyoung-Jin Kim,Shigeru Obayashi,Kazuhiro Nakahashi 한국전산유체공학회 2000 한국전산유체공학회 학술대회논문집 Vol.2000 No.5

An aerodynamic design method has been developed by using a three-dimensional unstructured Euler code and an adjoint code with a discrete approach. The resulting adjoint code is applied to a wing design problem of supersonic transport with a wing-body-nacelle configuration. Hicks-Henne shape functions are adopted for the surface geometry perturbation, and the elliptic equation method is employed for the interior grid modification during the design process. Interior grid sensitivities are neglected except those for design parameters associated with nacelle translation. The Sequential Quadratic Programming method is used to minimize the drag with constraints on the lift and airfoil thickness. Successful design results confirm validity and efficiency of the present design method.

FLAP DEFLECTION OPTIMZATION FOR TRANSONIC CRUISE PERFORMANCE IMPROVEMENT OF SUPERSONIC TRANSPORT WING

Hyoung-Jin Kim,Shigeru Obayashi,Kazuhiro Nakahashi 한국전산유체공학회 2000 한국전산유체공학회 학술대회논문집 Vol.2000 No.10

Wing flap deflection angles of a supersonic transport are optimized to improve transonic cruise performance. For this end, a numerical optimization method is adopted using a three-dimensional unstructured Euler code and a discrete adjoint code. Deflection angles often flaps; five for leading edge and five for trailing edge, are employed as design variables. The elliptic equation method is adopted for the interior grid modification during the design process. Interior grid sensitivities are neglected for efficiency. Also tested is the validity of the approximate gradient evaluation method for the present design problem and found that it is applicable for leading edge flap design in cases of no shock waves on the wing surface. The BFGS method is used to minimize the drag with constraints on the lift and upper surface Mach numbers. Two design examples are conducted; one is leading edge flap design, and the other is simultaneous design of leading edge and trailing edge flaps. The latter gave a smaller drag than the former by about two counts.