Growth and Interaction of Sand Ripples Due to Steady Viscous Flow in an Annular Channel

抄録

An experimental study is made on the pattern formation of a sand bed immersed in a viscous fluid between two concentric cylinders of finite depth; the channel width is sufficiently large as compared with the particle size. The upper boundary of the fluid is in contact with an annular ring made of transparent acrylic resin, which slides at a constant angular velocity, whereas other boundaries are at rest. New results on the onset and growth of sand ripples, the propagation and interaction of the ripples, and the long-term behavior for adjusting to a constant wavelength are presented.