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Volume 30 (2010)
- Issue 119 Pages 03-
- Issue 118 Pages 01-
- Issue 117 Pages 1-
- Issue 116 Pages 2-
Volume 30, Issue 116
Displaying 1-6 of 6 articles from this issue
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Reviews
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Shigeyuki TOMIMATSU2010 Volume 30 Issue 116 Pages 2
Published: 2010
Released on J-STAGE: March 03, 2012
JOURNAL FREE ACCESSDownload PDF (153K) -
Chisachi KATO2010 Volume 30 Issue 116 Pages 3-8
Published: 2010
Released on J-STAGE: March 03, 2012
JOURNAL FREE ACCESSafter reviewing the progress in Computational Fluid Dynamics(CFD) that have take place for the past two decades, this article describes the present status of the leading-edge applications of CFD in engineering fields, and provides the author's personal forecast how CFD will develop in the coming decade, Even larger-scale computations that utilize several tenth billion computational grids will become feasible where such computations are expected to give the same level of accuracy that DNS(Direct Numerical Simulation) does. Along with this progress in the large-scale computations, the mathematical model for multi-scale physical phenomena such as aeroacoustics, cavitation, and combusting flows will also be advanced.Another progress expected for CFD is the achievement of very-fast computations of RANS (Reynolds Averaged Navier Stokes Simulation) and this will enable the full optimization of product design based on the results of CFD. This article also gives comments on those problems that have to be overcome in order to realize the expected achievements for CFD.View full abstractDownload PDF (3658K) -
Kyoji KAMEMOTO2010 Volume 30 Issue 116 Pages 9-14
Published: 2010
Released on J-STAGE: March 03, 2012
JOURNAL FREE ACCESSIn this paper, it is described that the view point of Lagrangian observation is usually more suitable than that of Eulerian observation for understanding of complex and unsteady vortex -flows. In order to investigate separation of boundary layers and formation of vortices, knowledge of physical meanings of vorticitiy is important. Fundamental factors in vortex fluid dynamics and essential concept of vortex method are explained from the view point of Lagrangian observation. Furthermore, results of numerical experience of starting flow vortex formation from an aerofoil and vortical flow around a swimming fish are introduced.View full abstractDownload PDF (1643K) -
Makoto YAMAMOTO2010 Volume 30 Issue 116 Pages 15-20
Published: 2010
Released on J-STAGE: March 03, 2012
JOURNAL FREE ACCESSVortical flow is one of the major sources for generating aerodynamic losses in a turbine blade passage. Therefore, a great number of numerical and experimental studies have been made to suppress the vortices actively or passively. In the present article, the vortices in a turbine and the losses were briefly introduced, and then the computational investigation on the effect of the slot injection from the tip platform of a turbine blade was described. It was indicated that (1) the slot injection has some potential to control the tip leakage vortex, (2) the small amount of injection flow rate can weaken the strength of the tip vortex, but the total loss increases, and (3) the large amount of injection flow rate can make the tip vortex disappear, but the loss near the casing wall increase.View full abstractDownload PDF (4922K) -
Kenichiro TAKEISHI, Masaaki MATSUURA, Masaharu KOMIYAMA2010 Volume 30 Issue 116 Pages 21-27
Published: 2010
Released on J-STAGE: March 03, 2012
JOURNAL FREE ACCESSToday, the turbine inlet temperature of an industrial gas turbine reaches a level of 1500 degree C. And the complicated cooling structure was adopted for turbine vanes and blades to maintain their lives. Complicated vortices system and strong secondary flow were generated in the flow passage of turbine nozzles and blades. These flow fields affect the heat transfer of an airfoil and endwall, and it is very important to understand these phenomena to design high temperature turbine blade and vanes. Turbine flow and heat transfer tests have been conducted using stationary cascade test facilities and rotating rigs. In this commentary, the visualization methods to apply turbine cascade tests to visualize vortices system, secondary flow and mixing phenomena of film cooling air with main stream and their typical visualization test results are presented.View full abstractDownload PDF (8289K) -
Lingjia ZHAO2010 Volume 30 Issue 116 Pages 28-33
Published: 2010
Released on J-STAGE: March 03, 2012
JOURNAL FREE ACCESSLarge pump and axial pump are sensitive to adverse vortices in pump sump. The sump should be designed to prevent free-surface and submerged vortices within the fixed limits, and allow the pump to achieve its optimum hydraulic performances. This paper illustrates the visualization methods and examples of vortices in pump sump by experiment and CFD. In TSJ standard for model test vortex types are identified by the naked eye, while in HI standard vortices are visualized with the help of dye and artificial debris. Both in these standards, free-surface and submerged vortices entering the pump must be less severe than the acceptance criteria. Recently CFD for vortex prediction in pump sump has developed rapidly. RANS and LES methods can be classified according to the difference of viscosity model. RANS method has important achievements due to the actual calculation cost.View full abstractDownload PDF (4535K)
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