Document Type : Full Lenght Research Article
Department of Fluid Mechanics, Academy of Hakusan Dynasty
Academy of Hakusan, 2-14, Meiko, Hakusan 920-2152 Japan.
This paper is concerned with longitudinal vortex rolls in fluids. The longutudinal rolls are observed in the sea surface, desert, and atmosphere. However, origin of the vortical motions are not clear, so that in this study laboratory experiments and theoretical analyses have been conducted to elucidate the formation mechanism of the longitudinal vortex rolls in laboratory . As the results, it becomes clear that these vortex rolls are generated by the interaction of the thermal convection and the shear force by the flow. That is, as far as these two effects are existed, irrespective of other conditions are different, quite similar longitudinal vortex rolls appear. Take for example, in dayly our lives when it is fine, we often ovserve longitudinal vortex rolls in the sky, when we look through the outside from the airplane window, we see the longitudinal rows of clouds, and when wo go on board , we notice the longitudinal wave lines on the sea surface.