Parametric Sensitivity Analyses of Mudflow Rheology with Depth-Averaged Model

This study used a one-dimensional (1D) depth-averaged model using the Constrained Interpolation Profile (CIP) scheme to simulate mudflow and analyze the sensitivity of different rheological models to rheological parameters based on flow profile and flow propagation behaviour. The selection of rheological models in mudflow simulation significantly affects the resulting mudflow profile. Thus, this study investigates how different rheological models influence the mudflow profile and the role of rheological parameters in flow resistance. Three rheological models are used in this study, i.e. the Simplified Bingham, Quadratic, and Turbulent & Yield models for parametric sensitivity analysis. The analysis is conducted by comparing the mudflow profiles produced by each model and examining how the choice of rheological model and parameters influences the results. The results show that the Quadratic and Turbulent & Yield models exhibit similar sensitivity to pseudo-Manning's coefficient. When pseudo-Manning’s coefficient is neglected, the Quadratic model is more sensitive to fluid viscosity compared to the Simplified Bingham model in high yield stress condition, while the Turbulent & Yield model shows the highest sensitivity to yield stress among these three rheological models. Under the same rheological parameter value, Simplified Bingham model results in the shortest front-end distance, followed by the Quadratic model, while the Turbulent and Yield model produced the furthest front-end distance due to the different inclusion of rheological terms in the models. These findings emphasize the necessity of selecting an appropriate rheological model and calibrating parameters in accordance with the specific flow characteristics and simulation conditions to ensure precise predictions of mudflow dynamics.