Influence of Canal Topography on Ship Waves in Shallow Water

The waves generated by ships sailing on rivers or canals differ much from those in the open deep sea. Shallow water waves are typically steeper and, hence, nonlinear. They can damage river banks and endanger other ships. Natural rivers and artificial canals are getting increasingly too small for the present and future traffic. To survive in today's aggressive competition between different modes of transport inland ships have to become larger and faster. With increasing ship size the ratio of water depth to draft is getting smaller and, hence, fairways need to be dredged. In this work the influence of the bottom topography of a canal on the waves generated by a ship at near-critical speed is studied. The wave pattern is found to differ significantly from the horizontal bottom case. Moreover, the danger arising from a ship sailing in a canal at an ill-adapted speed is pointed out. The calculations are based on shallow-water wave equations of the Boussinesq type, which have been previously used to successfully simulate the waves generated by a ship in a canal with a horizontal bottom, see Jiang & Henn (1999).