Improvements in the Application Of the Numerical Method of Characteristics To Predict Attenuation in Unsteady Partially Filled Pipe Flow.

The use of linear interpolation and simplified iteration procedures are shown to introduce inaccuracies to the rectangular grid method of characteristics, particularly when applied to subcritical flows. Comparisons of experimental and computational results are presented illustrating the use of Everett and Newton-Gregory interpolation, in addition to a more complex iteration procedure, to substantially improve the method's ability to maintain both steady uniform flows under subcritical conditions, and retain wave steepness during propagation along the drainage pipe. The results presented will be directly applicable to the building drainage network model previously developed at Brunei University with the support of NBS CBT grant aid.