Accuracy of the ISIS bridge methods for prediction of afflux at high flows

Abstract

AbstractThis paper presents the experimental results and findings from investigation into the accuracy, capability and suitability of the ISIS software package to model flow through bridge structures. Different types of bridge models, in terms of soffit shape, set in a two‐stage channel with various roughness conditions, were used for this study. In order to simulate natural environmental conditions, the original experimental data were scaled up using the undistorted‐scale method. One‐dimensional ISIS bridge methods, the ARCH bridge method, USBPR bridge method and the Bernoulli loss unit, were applied to both original experimental data and the scaled‐up data. The results for the ARCH bridge method and the USBPR method of ISIS are significantly different from the measured data and the Bernoulli loss unit. The Bernoulli loss unit, which uses Bernoulli's equation in ISIS, is the most accurate method to compute the afflux of bridges in waterways.