Behavior of the Hairpin Votex in a Laminar Boundary Layr of Surfactant Solution

表面活性剂溶液层流边界层中发夹旋涡的行为

• 批准号: 06650203
• 负责人: ITOH Motoyuki
• 金额: $ 1.34万
• 依托单位: Nagoya Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650203/
• 关键词: drag reduction; surfactant solution; hairpin vortex; low-speed streak; flat-plate boundary layr; hydrogen bubble method; dye injection technique

In order to clarify the mechanism of drag-reduction in the turbulent flow of a surfactant solution, the behavior of hairp in vortex generated continuously or solitary in a laminar flat-plate boundary layr was investigated experimentally. The results obtainedare as follows.[continuously generated hairpin vortex](1)The frequency of hairpin generation is lower in the flow of surfactant solution than in the water flow.(2)In the flow of surfactant solution, both the kinked region of the vortex legs and the secondary votex are hard to develop.(3)At downsream location, multiple low-speed streaks are observed in the water flow. On the other hand, only single low -speed streak can be observed in the flow of surfactant solution.(4)The ratio of the convecting velocity of the vortex head to the local flow velocity is smaller in the surfactant solution thon in the water.(5)The angle between the neck of hairpin vortex and the wall is smaller in the flow of surfactant solution[single hairpin vortex](1)In order to generate a single hairpin vortex in the flow of surfactant solution, the speed of the infecting jet must be higher and the duration time must be shorter.(2)The hairpin vortex in the flow of surfactant solution does not develop if the shear rate is higher than the critical value for the shear inducing state.(3)The single hairpin vortex can be generated for the limiting conditions.

为了阐明表面活性剂溶液湍流中拖延的机理，在实验中研究了在层状平板边界中连续产生的涡流中发夹的行为。 [连续生成的发夹涡流]（1）表面活性剂溶液的流动频率比水流流的频率低。（2）在表面活性剂溶液的流动中，涡流腿的扭结区域和次级投票都很难形成。另一方面，在表面活性剂溶液的流动中只能观察到单个低速条纹。（4）（4）在水中的表面活性剂溶液中，涡流头与局部流速的对流速度的比率较小。表面活性剂溶液流中的单个发夹涡旋，感染喷气的速度必须更高，并且持续时间必须更短。（2）如果表面活性剂溶液流中的发夹涡旋不会发展，如果剪切速率高于诱导剪切状态的临界值。

项目成果

遠山尚久: "界面活性剤水溶液中のヘアピン渦の挙動" 日本機械学会流体工学部門講演会講演論文集. 1. 107-108 (1994)

Naohisa Toyama：“表面活性剂水溶液中发夹涡流的行为”日本机械工程师学会流体工程分会论文集 1. 107-108 (1994)。

Naohisa TOHYAMA: "The Behavior of Hairpin Vortices in a Surfactant Solution" Preprint for the JSME Fluid Engineering Division meeting. Vpl.1. 107-108 (1994)

Naohisa TOHYAMA：“表面活性剂溶液中发夹涡流的行为”JSME 流体工程分部会议的预印本。

遠山尚之: "界面活性剤水溶液中のヘアピン渦の挙動" 日本機械学会流体工学部門講演会講演論文集. 1. 107-108 (1994)

Naoyuki Toyama：“表面活性剂水溶液中发夹涡流的行为”，日本机械工程师学会流体工程学部会议记录，1. 107-108 (1994)

伊藤基之: "界面活性剤水溶液の境界層流れ中におけるヘアピン渦の挙動" 日本機械学会流体工学部門講演会講演論文集. 1. 103-104 (1995)

Motoyuki Ito：“表面活性剂水溶液边界层流动中的发夹涡流行为”日本机械工程师学会流体工程学会论文集 1. 103-104 (1995)。

Motoyuki ITOH: "The Behavior of Hairpin Vortices in a Laminar Boundary Layr of an Aqueous Surfactant Solution" Preprint for the JSME Fluid Engineering Division meeting. Vpl.1. 103-104 (1995)

Motoyuki ITOH：“水性表面活性剂溶液层流边界层中发夹涡旋的行为”，JSME 流体工程部门会议的预印本。