Friday 19 Jan 2018: Modelling Boundary Shear Stress Distribution in Open Channels Using a Face Recognition Technique
Dr Soroosh Sharifi - University of Birmingham
Harrison 170 14:30-15:30
Measuring local shear stress along an open channel’s boundaries is difficult and costly owing to the complexity of the turbulent velocity field, presence of flow structures, and the small magnitude of the stress. Shear stress also represents a difficult parameter to calculate due to the variability of channel slope, geometry and flow structures which are the main influencing factors in the complex flow process. To date, all the developed methods are inherently based on some sort of simplifying assumption, and therefore, the problem of accurately estimating these stresses has only been partially resolved. This work introduces a novel method based on recurrence plot analysis and a face recognition technique to model boundary shear stress distribution in open channels. In this approach, a synthetic database of images representing normalized shear stress distributions is formed from the training data set using recurrence plot analysis. A face recognition algorithm is then employed to synthesise the recurrence plots and transform the original database into short-dimension vectors containing similarity weights proportional to the principal components of the distribution of images (Figure 1 - see link below). These vectors capture the intrinsic properties of the boundary shear stress distribution of the test cases in the training set, and are sensitive to variations of the corresponding hydraulic parameters. The process of transforming one-dimensional data series into vectors of weights is reversible, and therefore, shear stress distributions for unseen cases can be predicted. The proposed method is applied to open channels with circular and trapezoidal cross sections and the results are discussed.
Dr Soroosh Sharifi is a Lecturer in Water Engineering at the University of Birmingham (UoB) with over 10 years of expertise in numerical modelling, data modelling, calibration and uncertainty analysis of hydro-environmental systems. Before joining UoB, Sharifi was a post-doctoral researcher at Catholic University of America where he was involved in several research projects including design and optimization of Green Infrastructures (GIs) and urban stormwater pollution source identification. In addition to these topics, Sharifi’s other areas of research interest include environmental hydraulics, urban drainage and climate change impact analysis.