My current interest in fluid mechanics is in flows involving shocks. In addition to traditional compressible flows, various incompressible flows also exhibit shock-like structures. A hydraulic jump is a well-known example, where the shock wave is a discontinuity in the fluid depth. Another example is furnished by a fluid flow inside a flexible tube (e.g. blood flow in arteries), where the shock is a jump in the tube cross section. Particle sedimentation, fluidization, flow of granular materials are often accompanied by shock-like transitions which can be treated by means of the theory of hyperbolic systems.