Pipe roughness identification of water distribution networks: A Tensor method

The identification of pipe roughnesses in a water distribution network is formulated as a nonlinear system of algebraic equations which turns out to be demanding to solve under real-world circumstances. This paper proposes an enhanced technique to numerically solve this identification problem, extending the conventional Newton–Raphson approach with second-order derivatives in the determination of the search direction. Despite the requirement to solve a nonlinear equation to obtain a search direction, the application of the Hadamard/Schur product operator enables the resulting formulation to be represented compactly and thus facilitates the development of an efficient and more robust solving-technique. Algorithms on the basis of this more enhanced solving method are then compared to a customized Newton–Raphson approach in simulation examples.