Abstract
Side jets are generated in round jets by causing self-excited oscillations when the density of issuing fluid is sufficiently lower than that of the ambient fluid. The side jets in a helium gas jet rotate slowly in the azimuthal direction. In this case, both the varicose and spiral modes are unstable. While, self-excited oscillations are produced in a two-dimensional jet with low-density fluid. However, the side-jet formation in the plane jet not has been confirmed until now. An aim of this study is that the side-jet formation in two-dimensional jets is examined using flow visualization. When the self-excited oscillations are generated in the initial region of the plane jet, the side jets are formed. In this case, the spiral mode does not appears.
