Yee-Chung Jin

MPS-Based Mesh-Free Particle Method for Modeling Open-Channel Flows

Dealing with large deformation and fragmentation of geometries and interfaces (e.g., free surfaces), the regular mesh-based Eulerian methods, such as finite-element and finite-difference methods, have difficulties in fluid-flow modeling. Recently, studies have focused on a new generation of numerical methods called mesh-free particle (Lagrangian) methods. In this study, a mesh-free particle method based on the moving-particle semi-implicit (MPS) particle-interaction model has been developed for simulation of open-channel flow. The model is able to simulate viscous fluid flow with large deformation and fragmentation of free surface in practical fields. Moreover, the model is capable of modeling open-channel problems with both inflow and outflow and inconstant numbers of particles. The model has been validated and applied to some common sample problems. The results show the reasonable accuracy of the model. The final model is capable of modeling free-surface deformation and fragmentation as well as accurate...

Arsenic in water supplies

The paper examines the presence of arsenic in drinking water supplies and discusses the health effects. Information is presented on the source of arsenic, the method in which sediments remove arsenic from the surface water, and the processes by which arsenic can be released from the sediments back into the water. Water treatment practices related to arsenic removal from water are discussed. Arsenic levels in the Regina/Moose Jaw water distribution system are presented, along with an examination of the factors that may release arsenic held in the sediments in Buffalo Pounds Lake, the source of water supply for Regina and Moose Jaw. Based on the analysis of data, the possibility of reaching enhanced arsenic levels in Buffalo Pounds Lake through transfer from sediments is low; however, regular monitoring of arsenic in the lake water and distribution system is advisable.

A mesh-free method boundary condition technique in open channel flow simulation

The mesh-free particle method has been successfully used in simulation of various types of flow. Small particle distance is typically used for representing the form of the simulation domain, requiring a large amount of computing time, accordingly, and, thus, seriously affecting the efficiency of the mesh-free method. In order to optimize the efficiency and accuracy of the mesh-free method in simulating open channel flow, a new approach based on the assigning velocity to ghost particles next to the solid boundary is developed. This ghost particle velocity correction also considers the bed roughness, the flow depth and the particle distance all together so that larger particle distance can be used in open channel flow simulations with the mesh-free method, requiring less simulation time, while the correct velocity distribution over depth is still maintained. Experimental cases are used to compare the numerical results to show the advantages of using this improved method.

Flow over sills by the MPS mesh-free particle method

A particular flow structure and the behaviour of free surface complicate flow modelling over sills, especially if the free surface is highly deformed and made up of spray. Mesh-free particle methods have recently been developed to increase the flexibility and accuracy of numerical methods to deal with these boundaries and interfaces. This research aims to develop, apply, and evaluate the capabilities of one of the particle methods, the moving particle semi-implicit method, for modelling flow over sills under various flow regimes. The model developed, along with modifications in its pressure calculation and boundary definition techniques, is applied to predict the free surface and the velocity profiles of sill flow. These results are compared with experimental measurements and results from other numerical techniques. They are demonstrated to agree well with the experiments, indicating that the model simulates velocity profiles and free surface fluctuations reasonably.

Numerical investigation of flow in pool-and-weir fishways using a meshless particle method

ABSTRACT A Lagrangian meshless particle method (moving particle semi-implicit method; MPS) has been widely applied to simulate engineering problems. In this study, a new solid boundary treatment using imaginary particles instead of traditionally predefined ghost particles is developed to accommodate sharp edges in addressing practical problems. The proposed solid boundary treatment in the weakly compressible MPS (WC-MPS) model is verified for a sharp-crested weir flow, and then applied to simulate flow in pool-and-weir fishways with thin walls, which can be considered as a flow system with a series of weirs. It was found that flow characteristics in pool-and-weir fishways can be determined for given design parameters such as pool length, height of weir, fishway bed slope, and water discharge. The plunging flow and skimming flow observed in experiments are reproduced successfully by the WC-MPS model. Simulated results demonstrate satisfactory agreement with experimental data.

Minimizing the negative effect of the overlapping pixels on the classification accuracy of the error back-propagation neural network classifier using the ancillary and supplemental data

A procedure is presented for minimizing the problems associated with the overlapping land cover spectral signatures on the classification accuracy, which involves the use of ancillary and supplemental data in remote sensing classification. Multispectral remote sensing data from a section of Kananaskis Country in the Rocky Mountains in Canada were used as an application for this investigation. A technique was established to simplify the method of selecting the dataset of the spectral training sample that can be used to determine decision rules for classifying the application area and improving the sorting process between the overlapping pixels. A three-stage computer classifier model was developed based on the back-propagation artificial neural network method to enhance the sorting process among land cover types that have similar spectral signatures. The performance of this computer model was assessed by comparing the results with the results of three prepackaged computer classifiers using the same dataset: maximum likelihood, minimum distance to means, and parallelepiped. The investigation demonstrated that the developed computer model performed satisfactorily overall with the use of the proposed enhanced sorting procedure.

Municipal Wastewater Effluent Strategy: Studies to Determine the Effluent Discharge Objectives for Wastewater Treatment Plants in Saskatchewan, Canada

Municipal wastewater usually contains many substances that may have risks for human health and environment protection. The Canadian Council of Ministers of Environment (CCME) has developed a Canada-wide Strategy for the Management of Municipal Wastewater Effluent (also called MWWE Strategy) for effluent discharged into surface water from wastewater treatment plants. The Strategy requires all municipal wastewater treatment plants in Canada including Saskatchewan that are discharging effluent into fish-bearing waters to achieve National Performance Standards (NPS) and develop site-specific Effluent Discharge Objectives (EDOs). The strategy also helps to better manage the wastewater facilities and to set up the standard for the future new facilities (CCME, 2009).

Managing Water Quality in Saskatchewan Municipal Distribution Systems

High quality water is paramount in protecting and maintaining natural ecosystems and the species that depend upon them, ensuring the productivity of industry, sustaining commerce and growth. Safe drinking water is a vital component in the protection of public health and disease prevention and therefore essential for the health and well-being of citizens across the globe. In the province of Saskatchewan, Canada, the quality of drinking water, the conditions of systems that produce it and the protection of source water is one of the top priorities and continues to be an important public health and environmental goal. As such, ensuring safe drinking water is a shared responsibility amongst a number of provincial ministries and agencies including ministries of Environment, Health and Municipal Affairs and Saskatchewan Water Corporation. Key partners outside the provincial government include the federal government through Health Canada and various infrastructure funding initiatives, municipalities and other waterworks owners, the Saskatchewan Urban Municipalities Association, the Saskatchewan Association of Rural Municipalities, the Saskatchewan Water and Wastewater Association, and the Operator Certification Board. This paper includes the results of sampling/research studies that are conducted to determine the levels of Haloacetic acids (HAA5), Trihalomethanes (THMs) and N- nitrosodimethylamine (NDMA) in Saskatchewan municipal distribution systems. This paper also outlines the regulatory framework, water management and activities undertaken by the Government of Saskatchewan, Canada to manage drinking water in the province.

Distributions of velocity, turbulence, and suspended sediment over low relief-antidunes

By D.G. WREN, S.J. BENNETT, B.D. BARKDOLL and R.A. KUHNLE, Journal of Hydraulic Research, IJHR, Volume 43, 2005, Issue 1, pp. 3–11