Rotating Solitary Wave during Liquid Drainage

This work reports on the observation of a rotating solitary wave during liquid drainage from a cylindrical reservoir when shallow water conditions are reached. Using results obtained from a high-speed camera and image processing techniques, we discuss the mechanism leading to the formation of the solitary wave; and we examine its shape and speed as it propagates in two different cases, variable and constant water depths. The results were also compared to the KdV theory.