Applied Pipe Roughness Identification of Water Networks: Consideration of All Flow Regimes

This article presents a mathematically rigorous unification of the pipe roughness identification problem of water distribution networks considering all Reynolds regimes, i.e., laminar, turbulent, as well as transitional flow regimes. Although the identification procedure is based on steady-state hydraulic network equations, the identified roughness parameters are also key for dynamic models that can be used for model-based controller and observer designs. While a three-cycle network simulation example serves to illustrate the presented problem formulation and solution in an extensive manner, the application on a real-world drinking water network is in focus. In addition, vital aspects, such as topology simplifications of the underlying network and the importance of the generation and selection of independent measurement sets, are addressed. We apply root-finding methods instead of methods based on optimization and thereby show that the pipe roughness identification problem may actually be applicable to identify as well as locate leakages.