Instability of Mud Flow through Irregular Channel
Date Issued
2012
Date
2012
Author(s)
Wei, Shih-Chao
Abstract
Debris flow is a major disaster in Taiwan. Nevertheless, the mitigation and prediction of debris flow disaster are still not technically achievable. One of the reason is a lack of information on the growth of debris flow. Therefore, we expected to find the growth of any small disturbance of debris flows by classic instability analysis. However, there is more constitutive laws to describe different debris fluids. We chose the mud fluids to research and used Bingham fluids model.
In this study, we try to analyze instability problem in mud flows through the channel with disturbance on side bank and bed. For these objectives to be achieved, the article is structured as follows. We first solve the steady uniform flow analytically in rectangular channel, then invoked a small perturbation on the channel’s boundaries. Through the linear instability analysis, we study the flow condition from stable to unstable.
Results show that the flow condition is determined unconditional unstable with time. The long wave motion is more stable than short wave, and the flow tend to be more and more unstable for the larger gravity effect or the lower yield stress. In the spatial instability, there is more unstable since the flow’s wavelength is the same as forcing wavelength. The bed forcing is more important than side bank in wide channel, otherwise the side bank forcing is more important in narrow channel.
Subjects
Mud flow
Linear Instability Analysis
Bingham fluid
SDGs
Type
thesis
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