It is well known that the drag-reducing effect is obtained in a surfactant solution flow in a straight pipe. We investigate about a viscoelastic fluid flow such as a surfactant solution flow in a square-section 90...It is well known that the drag-reducing effect is obtained in a surfactant solution flow in a straight pipe. We investigate about a viscoelastic fluid flow such as a surfactant solution flow in a square-section 90° bend. In the experimental study, drag-reducing effect and velocity field in a surfactant solution flow are investigated by measurements of wall pressure loss and LDV measurements. For the numerical method, LES with FENE-P model is used in the viscoelastic fluid flow in the bend. The flow characteristics of viscoelastic fluid are discussed compared with that of a Newtonian fluid.展开更多
The major causes of the sound pressure level (SPL) variation due to the changes of the inclined angle of a circular cylinder and the aspect ratio (ratio of distance between endplates to cylinder diameter) were investi...The major causes of the sound pressure level (SPL) variation due to the changes of the inclined angle of a circular cylinder and the aspect ratio (ratio of distance between endplates to cylinder diameter) were investigated. The velocity fluctuation of the wake and the surface pressure fluctuation of the cylinder were measured in a low noise wind tunnel to find the correlation length, coherent output power and Strouhal number. The results show that the changes of these values qualitatively correspond with the change of SPL. Flow visualization tests are performed to clarify the variation of wake in relation with inclined angle and aspect ratio. It is found that the spanwise structure of Karman’s vortex street is broken down by the upward flows generated around the bottom endplate, and the degree of the interference between the upward flow and Karman’s vortex street is smaller when the aspect ratio is larger.展开更多
In order to develop the practical approximation models suitable to flow fields at low Mach number with large temperature difference, the influence of difference in approximation models on numerical solutions was inves...In order to develop the practical approximation models suitable to flow fields at low Mach number with large temperature difference, the influence of difference in approximation models on numerical solutions was investigated by solving the natural convection in the 3-D enclosures with vertical sidewalls differentially heated and the heated bottom wall using 3 approximation models, that is Boussinesq approximation, low Mach Number approximation and approximation model proposed by Mlaouah. As results of the simulation, the effects of the differences in the three approximation models on the numerical solutions become clear.展开更多
最近，当半导体仪器变得更复杂，高技术的开发在生产半导体的进程为薄一致电影的形成被要求了。旋转涂层通常被使用在晶片表面上散布光致抗蚀剂。然而，自从旋转，磁盘的速度在旋转涂层很高，扔的光致抗蚀剂向外散布并且在电影表面上重...最近，当半导体仪器变得更复杂，高技术的开发在生产半导体的进程为薄一致电影的形成被要求了。旋转涂层通常被使用在晶片表面上散布光致抗蚀剂。然而，自从旋转，磁盘的速度在旋转涂层很高，扔的光致抗蚀剂向外散布并且在电影表面上重新依附。钩子杯在纺纱在晶片外面被建立涂层，和散布光致抗蚀剂薄雾被在在晶片边和钩子杯之间的差距产生的 exhaust 流动从晶片边移开。在旋转涂层的干燥过程，是一颗严肃的担心在低旋转的情况中的晶片边附近的电影厚度增加加速。这研究的目的是在晶片表面和液膜的弄干的率上在 3D 界面层流动上弄明白钩子杯几何学的效果。展开更多
Recently, development of high technology has been required for abe fomaafion of thin uniform film in manufacturing processes of semiconductor as the semiconductor become more sophisticated. Spin coating is usually use...Recently, development of high technology has been required for abe fomaafion of thin uniform film in manufacturing processes of semiconductor as the semiconductor become more sophisticated. Spin coating is usually used for spreading photoresist on a wafer surface. However, since rotating speed of the disk is very high in spin coating, the dropped resist scatters outward and reattaches to the film surface. So, the scattered resist is removed by the exhaust flow generated at the gap between the wafer edge and the catch cup. It is seriously concerned that the stripes called Ekman spiral vortices appears on the disk in the case of high rotating speed and the film thickness increases near the wafer edge in the case of low rotating speed, because it prevent the fomation of uniform film. The purpose of this study is to make clear the generation mechanism of Ekman spiral vortices and the influence of exhaust flow on it. Moreover the influence of the catch cup geometry on the wafer surface boundary layer flow is investigated.展开更多
文摘It is well known that the drag-reducing effect is obtained in a surfactant solution flow in a straight pipe. We investigate about a viscoelastic fluid flow such as a surfactant solution flow in a square-section 90° bend. In the experimental study, drag-reducing effect and velocity field in a surfactant solution flow are investigated by measurements of wall pressure loss and LDV measurements. For the numerical method, LES with FENE-P model is used in the viscoelastic fluid flow in the bend. The flow characteristics of viscoelastic fluid are discussed compared with that of a Newtonian fluid.
文摘The major causes of the sound pressure level (SPL) variation due to the changes of the inclined angle of a circular cylinder and the aspect ratio (ratio of distance between endplates to cylinder diameter) were investigated. The velocity fluctuation of the wake and the surface pressure fluctuation of the cylinder were measured in a low noise wind tunnel to find the correlation length, coherent output power and Strouhal number. The results show that the changes of these values qualitatively correspond with the change of SPL. Flow visualization tests are performed to clarify the variation of wake in relation with inclined angle and aspect ratio. It is found that the spanwise structure of Karman’s vortex street is broken down by the upward flows generated around the bottom endplate, and the degree of the interference between the upward flow and Karman’s vortex street is smaller when the aspect ratio is larger.
文摘In order to develop the practical approximation models suitable to flow fields at low Mach number with large temperature difference, the influence of difference in approximation models on numerical solutions was investigated by solving the natural convection in the 3-D enclosures with vertical sidewalls differentially heated and the heated bottom wall using 3 approximation models, that is Boussinesq approximation, low Mach Number approximation and approximation model proposed by Mlaouah. As results of the simulation, the effects of the differences in the three approximation models on the numerical solutions become clear.
基金the 21~(st)Century COE program of Pulse Power Science of Kumamoto University
文摘最近，当半导体仪器变得更复杂，高技术的开发在生产半导体的进程为薄一致电影的形成被要求了。旋转涂层通常被使用在晶片表面上散布光致抗蚀剂。然而，自从旋转，磁盘的速度在旋转涂层很高，扔的光致抗蚀剂向外散布并且在电影表面上重新依附。钩子杯在纺纱在晶片外面被建立涂层，和散布光致抗蚀剂薄雾被在在晶片边和钩子杯之间的差距产生的 exhaust 流动从晶片边移开。在旋转涂层的干燥过程，是一颗严肃的担心在低旋转的情况中的晶片边附近的电影厚度增加加速。这研究的目的是在晶片表面和液膜的弄干的率上在 3D 界面层流动上弄明白钩子杯几何学的效果。
文摘Recently, development of high technology has been required for abe fomaafion of thin uniform film in manufacturing processes of semiconductor as the semiconductor become more sophisticated. Spin coating is usually used for spreading photoresist on a wafer surface. However, since rotating speed of the disk is very high in spin coating, the dropped resist scatters outward and reattaches to the film surface. So, the scattered resist is removed by the exhaust flow generated at the gap between the wafer edge and the catch cup. It is seriously concerned that the stripes called Ekman spiral vortices appears on the disk in the case of high rotating speed and the film thickness increases near the wafer edge in the case of low rotating speed, because it prevent the fomation of uniform film. The purpose of this study is to make clear the generation mechanism of Ekman spiral vortices and the influence of exhaust flow on it. Moreover the influence of the catch cup geometry on the wafer surface boundary layer flow is investigated.
