ABSTRACT

This chapter aims to introduce the basic concepts and methods used in fixed boundary, open-channel system modelling. It provides a mathematical description of open-channel flow processes in the form of partial differential equations (PDEs). All the existing software packages for open-channel-flow modelling use numerical techniques to solve approximations of the governing PDEs, thus providing an approximation of the exact solution. As interest in environmental processes in open channels grew, physical modelling of open-channel flow went through a renaissance and firmly remains an important modelling discipline – particularly as part of hybrid modelling. The basis of aerodynamic modelling of open-channel flow is the conversion of free-water surface flow to flow in a pressurized conduit by substituting a smooth surface for the air-water interface. The chapter presents the design and operation of open-channel-flow models on the assumption that the appropriate boundary conditions are observed in order to avoid, or at least minimize, the scale effect.