二次元衝突噴流の流れ場に存在する大規模変動の研究

抄録

There have been many investigations which deal with the large-scale fluctuation existing in the flow fields of the developed region of a two-dimensional free jet. However most of them have been made using a jet which has a top-hat velocity profile at the nozzle exit. The objective of the present investigation is to compare the characteristics of large-scale structures existing in two types of flow of the two-dimensional free jet, where the exit velocity profile is the "top-hat" type or "fully developed" type. We also studied the flow fields of a two-dimensional impinging jet. First, it was elucidated that the large-scale fluctuation also existed in the flow field of a fully developed jet. Dimensionless frequency in the initial region of the large-permaneny hyphon scale fluctuation obtained from x-direction data was proportional to the dimensionless distance to the power of - 1/3, and that obtained from y-direction data, to the power of - 2/3, instead of the power of - 3/2 obtained in the developed region of the two-dimensional free jet. Second, it was ascertained that the same kind of large-scale fluctuation as in the flow field of the developed region of the two-dimensional free jet also existed in the flow field of the two-dimensional impining jet.