Michael Ortiz是加州理工学院航窄与机械工程Dotty和DickHayman教授，关国文理研究院院上，由于其存1998—2007年间的出色研究成果荣获ICTAM2008年度RodneyHill奖．RodneyHill固体力学奖和Batch-elor流体力学奖是国际理论与应用力学联...Michael Ortiz是加州理工学院航窄与机械工程Dotty和DickHayman教授，关国文理研究院院上，由于其存1998—2007年间的出色研究成果荣获ICTAM2008年度RodneyHill奖．RodneyHill固体力学奖和Batch-elor流体力学奖是国际理论与应用力学联合会（International Union of Theoretical and Applied Mechanics，IUTAM）设立的，旨在表彰获奖者过去10年中存其力学分支学科研究中所取得的重要贞献．Ortiz教授是RodneyHill奖的第一位获奖人．展开更多
Current methodologies used for the inference of thin film stress through curvature measurements are strictly restricted to stress and curvature states which are assumed to remain uniform over the entire film/substrate...Current methodologies used for the inference of thin film stress through curvature measurements are strictly restricted to stress and curvature states which are assumed to remain uniform over the entire film/substrate system. By considering a circular thin film/substrate system subject to non-uniform, but axisymmetric misfit strain distributions in the thin film, we derived relations between the film stresses and the misfit strain, and between the plate system＇s curvatures and the misfit strain. These relations feature a “local” part which involves a direct dependence of the stress or curvature components on the misfit strain at the same point, and a “non-local” part which reflects the effect of misfit strain of other points on the location of scrutiny. Most notably, we also derived relations between the polar components of the film stress and those of system curvatures which allow for the experimental inference of such stresses from full-field curvature measurements in the presence of arbitrary radial non-uniformities. These relations also feature a “non-local” dependence on curvatures making a full-field measurement a necessity. Finally, it is shown that the interfacial shear tractions between the film and the substrate are proportional to the radial gradients of the first curvature invariant and can also be inferred experimentally.展开更多
In these years, a lot of environmental problems such as air pollution and exhaustion of fossil fuels have been discussed intensively. In our laboratory, a hydrogen-fueled propulsion system has been researched as an al...In these years, a lot of environmental problems such as air pollution and exhaustion of fossil fuels have been discussed intensively. In our laboratory, a hydrogen-fueled propulsion system has been researched as an alternative to conventional systems. A hydrogen-fueled propulsion system is expected to have higher power, lighter weight and lower emissions. However, for the practical use, there exist many problems that must be overcome. Considering these backgrounds, jet engines with hydrogen-fueled combustion within a turbine blade passage have been studied. Although some studies have been made on injecting and burning hydrogen fuel from a stator surface, little is known about the interaction between a tip leakage vortex near the suction side of a rotor tip and hydrogen-fueled combustion. The purpose of this study is to clarify the influence of the tip leakage vortex on the characteristics of the 3-dimensional flow field with hydrogen-fueled combustion within a turbine blade passage. Reynolds-averaged compressible Navier-Stokes equations are solved with incorporating a k-ε turbulence and a reduced chemical mechanism models. Using the computational results, the 3-dimensional turbulent flow field with chemical reactions is numerically visualized, and the three-dimensional turbulent flow fields with hydrogen combustion and the structure of the tip leakage vortex are investigated.展开更多
文摘Michael Ortiz是加州理工学院航窄与机械工程Dotty和DickHayman教授，关国文理研究院院上，由于其存1998—2007年间的出色研究成果荣获ICTAM2008年度RodneyHill奖．RodneyHill固体力学奖和Batch-elor流体力学奖是国际理论与应用力学联合会（International Union of Theoretical and Applied Mechanics，IUTAM）设立的，旨在表彰获奖者过去10年中存其力学分支学科研究中所取得的重要贞献．Ortiz教授是RodneyHill奖的第一位获奖人．
文摘Current methodologies used for the inference of thin film stress through curvature measurements are strictly restricted to stress and curvature states which are assumed to remain uniform over the entire film/substrate system. By considering a circular thin film/substrate system subject to non-uniform, but axisymmetric misfit strain distributions in the thin film, we derived relations between the film stresses and the misfit strain, and between the plate system＇s curvatures and the misfit strain. These relations feature a “local” part which involves a direct dependence of the stress or curvature components on the misfit strain at the same point, and a “non-local” part which reflects the effect of misfit strain of other points on the location of scrutiny. Most notably, we also derived relations between the polar components of the film stress and those of system curvatures which allow for the experimental inference of such stresses from full-field curvature measurements in the presence of arbitrary radial non-uniformities. These relations also feature a “non-local” dependence on curvatures making a full-field measurement a necessity. Finally, it is shown that the interfacial shear tractions between the film and the substrate are proportional to the radial gradients of the first curvature invariant and can also be inferred experimentally.
文摘In these years, a lot of environmental problems such as air pollution and exhaustion of fossil fuels have been discussed intensively. In our laboratory, a hydrogen-fueled propulsion system has been researched as an alternative to conventional systems. A hydrogen-fueled propulsion system is expected to have higher power, lighter weight and lower emissions. However, for the practical use, there exist many problems that must be overcome. Considering these backgrounds, jet engines with hydrogen-fueled combustion within a turbine blade passage have been studied. Although some studies have been made on injecting and burning hydrogen fuel from a stator surface, little is known about the interaction between a tip leakage vortex near the suction side of a rotor tip and hydrogen-fueled combustion. The purpose of this study is to clarify the influence of the tip leakage vortex on the characteristics of the 3-dimensional flow field with hydrogen-fueled combustion within a turbine blade passage. Reynolds-averaged compressible Navier-Stokes equations are solved with incorporating a k-ε turbulence and a reduced chemical mechanism models. Using the computational results, the 3-dimensional turbulent flow field with chemical reactions is numerically visualized, and the three-dimensional turbulent flow fields with hydrogen combustion and the structure of the tip leakage vortex are investigated.
