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Articles 1 - 11 of 11
Full-Text Articles in Engineering
Numerical Study Of Flow Characteristics Around A 30° Yawed Circular Cylinder At R E = 10 4, Ran Wang, Shaohong Cheng, David S.K. Ting
Numerical Study Of Flow Characteristics Around A 30° Yawed Circular Cylinder At R E = 10 4, Ran Wang, Shaohong Cheng, David S.K. Ting
Civil and Environmental Engineering Publications
Unstable motions of bridge stay cables have been observed on site and in wind tunnel tests when a cable is yawed at certain orientations to wind. To uncover the underlying mechanisms, flow around a circular cylinder at a yaw angle of 30° has been numerically analyzed in the current study using delayed detached eddy simulation (DDES) at R e = 10 4 . A comparison with the reference normal flow case indicates the presence of a more coherent span-wise flow structure when the cylinder is yawed at 30°. The application of proper orthogonal decomposition further reveals that at this orientation, …
Numerical Study Of Roundness Effect On Flow Around A Circular Cylinder, Ran Wang, Shaohong Cheng, David S.K. Ting
Numerical Study Of Roundness Effect On Flow Around A Circular Cylinder, Ran Wang, Shaohong Cheng, David S.K. Ting
Civil and Environmental Engineering Publications
Imperfectly round bridge stay cable cross section is speculated to be a key factor for wind-induced large-amplitude cable vibrations observed on site. A delayed detached eddy simulation implemented in Open source Field Operation and Manipulation is used to investigate the flow structure around and in the near-wake of an imperfectly round circular cylinder and the corresponding aerodynamic forces at a Reynolds number of 104 and an attack angle of 0° or 45°. With the increase in roundness imperfection, both monotonic and non-monotonic changes of the mean surface pressure and the wake velocity are found when the cylinder is normal to …
Effect Of Yaw Angle On Flow Structure And Cross-Flow Force Around A Circular Cylinder, Ran Wang, Shaohong Cheng, David S.K. Ting
Effect Of Yaw Angle On Flow Structure And Cross-Flow Force Around A Circular Cylinder, Ran Wang, Shaohong Cheng, David S.K. Ting
Civil and Environmental Engineering Publications
Flow around an inclined circular cylinder at yaw angles of α = 0°, 30°, 45°, and 60° has been numerically studied using the delayed detached eddy simulation at a Reynolds number of 1.4 × 104. Periodic boundary conditions are utilized to minimize the end effect. The focus is to explore the effect of yaw angle on the flow structure and the spatial distribution of the cross-flow forces. For the normal flow case, the modulation of the span-wise averaged lift force coefficient is found to be related to the unstable shear layer. For the inclined cases, contours of the sectional lift …
Simulating The Role Of Axial Flow In Stay Cable Vibrations Via A Perforated Wake Splitter Plate, Ran Wang, Shaohong Cheng, David Ting
Simulating The Role Of Axial Flow In Stay Cable Vibrations Via A Perforated Wake Splitter Plate, Ran Wang, Shaohong Cheng, David Ting
Civil and Environmental Engineering Publications
The inclined and/or yawed orientation of bridge stay cables results in the formation of secondary axial flow on the leeward side of cable surface, which is believed to be one of the contributing factors exciting some unique wind induced cable vibration phenomena. To clarify the role of axial flow in triggering aerodynamic instability of stay cables, a numerical study has been conducted to indirectly examine the axial flow effect via a perforated splitter plate placed along the central line of a circular cylinder wake. By manipulating the perforation ratio of the perforated plate at four different levels, the variation of …
Effect Of Gap Flow On The Shallow Wake Of A Sharp-Edged Bluff Body – Turbulence Parameters, A.M Shinneeb, R. Balachandar
Effect Of Gap Flow On The Shallow Wake Of A Sharp-Edged Bluff Body – Turbulence Parameters, A.M Shinneeb, R. Balachandar
Civil and Environmental Engineering Publications
This experimental study was carried out to investigate the turbulent wake generated by a vertical sharp-edged flat plate suspended in a shallow channel flow with a gap near the bed. The objective of this study is to understand the effect of the gap flow on the turbulent wake by studying two different gap heights between the channel bed and the bottom edge of the bluff body. These two cases were compared to the no-gap case which is considered as a reference case. The maximum flow velocity was 0.45 m/s and the Reynolds number based on the water depthwas 45,000. Extensivemeasurements …
Mean Characteristics Of Fluid Structures In Shallow-Wake Flows, Ram Balachandar
Mean Characteristics Of Fluid Structures In Shallow-Wake Flows, Ram Balachandar
Civil and Environmental Engineering Publications
An enhanced picture of the formation of fluid structures including the effect of the free surface and the bed is captured via a numerical solution of flow past a bed mounted bluffbody. A numerical comparison for the fluid structures observed in a time-averaged field of the shallow-wake flow behind a bluffbody utilizing the rigid-lid assumption and volume of fluid method is carried out in this study to bring forth the shortcomings in previous studies. The transient three-dimensional governing Navier–Stokes equations are computationally solved using a finite volume technique with Detached Eddy Simulation as a turbu- lence model. A flat wave …
Effect Of Gap Flow On The Shallow Wake Of A Sharp-Edged Bluff Body –Mean Velocity Fields, A.M Shinneeb, R. Balachandar
Effect Of Gap Flow On The Shallow Wake Of A Sharp-Edged Bluff Body –Mean Velocity Fields, A.M Shinneeb, R. Balachandar
Civil and Environmental Engineering Publications
This experimental study was carried out to investigate the turbulent shallow wake generated by a vertical sharp-edged flat plate suspended in a shallow channel flow with a gap near the bed. The objective of this study is to understand the effect of the gap flow on the wake by studying two different gap heights between the channel bed and the bottom edge of the bluff body. These two cases will be compared to the no-gap case which is considered as a reference case. Themaximumflowvelocity was 0.45m/s and the Reynolds number based on the water depthwas 45,000. Extensivemeasurements of the flowfield …
A Multi-Objective Facility Location Model For Closed-Loop Supply Chain Network Under Uncertain Demand And Return, Saman Hassanzadeh Amin, Guoqing Zhang
A Multi-Objective Facility Location Model For Closed-Loop Supply Chain Network Under Uncertain Demand And Return, Saman Hassanzadeh Amin, Guoqing Zhang
Mechanical, Automotive & Materials Engineering Publications
A closed-loop supply chain (CLSC) network consists of both forward and reverse supply chains. In this paper, a CLSC network is investigated which includes multiple plants, collection centres, demand markets, and products. To this aim, a mixed-integer linear programming model is proposed that minimizes the total cost. Besides, two test problems are examined. The model is extended to consider environmental factors by weighed sums and ε-constraint methods. In addition, we investigate the impact of demand and return uncertainties on the network configuration by stochastic programming (scenario-based). Computational results show that the model can handle demand and return uncertainties, simultaneously.
A Proposed Mathematical Model For Closed-Loop Network Configuration Based On Product Life Cycle, Saman Hassanzadeh Amin, Guoqing Zhang
A Proposed Mathematical Model For Closed-Loop Network Configuration Based On Product Life Cycle, Saman Hassanzadeh Amin, Guoqing Zhang
Mechanical, Automotive & Materials Engineering Publications
Products may be returned over their life cycle. Industrial experiences show that there are three main return–recovery pairs. Commercial returns are repaired. End-of-use returns often are remanufactured. In addition, end-of-life returns are recycled. However, up to now, no optimization model is proposed for closed-loop configuration based on three return–recovery pairs. The repaired and remanufactured products can be sold in the same or secondary market. In this paper, we design and configure a general closed-loop supply chain network based on product life cycle. The network includes a manufacturer, collection, repair, disassembly, recycling, and disposal sites. The returned products are collected in …
Optimal Production Planning For A Multi-Product Closed Loop System With Uncertain Demand And Return, Jianmai Shi, Guoqing Zhang, Jichang Sha
Optimal Production Planning For A Multi-Product Closed Loop System With Uncertain Demand And Return, Jianmai Shi, Guoqing Zhang, Jichang Sha
Mechanical, Automotive & Materials Engineering Publications
We study the production planning problem for a multi-product closed loop system, in which the manufacturer has two channels for supplying products: producing brand-new products and remanufacturing returns into as-new ones. In the remanufacturing process, used products are bought back and remanufactured into as-new products which are sold together with the brand-new ones. The demands for all the products are uncertain, and their returns are uncertain and price-sensitive. The problem is to maximize the manufacturer's expected profit by jointly determining the production quantities of brand-new products, the quantities of remanufactured products and the acquisition prices of the used products, subject …
Coordinating Production And Recycling Decisions With Stochastic Demand And Return, Jianmai Shi, Guoqing Zhang, Jichang Sha, Saman Hassanzadeh Amin
Coordinating Production And Recycling Decisions With Stochastic Demand And Return, Jianmai Shi, Guoqing Zhang, Jichang Sha, Saman Hassanzadeh Amin
Mechanical, Automotive & Materials Engineering Publications
In this paper, the joint production and recycling problem is investigated for a hybrid manufacturing and remanufacturing system where brand-new products are produced in the manufacturing plant and recycled products are remanufactured into as-new products in the remanufacturing facility. Both the brand-new products and remanufactured products are used to satisfy customer demands. Returns of used products that are recycled from customers are assumed to be stochastic and nonlinearly price-dependent. A mathematical model is proposed to maximize the overall profit of the system through simultaneously optimizing the production and recycling decisions, subject to two capacity constraints — the manufacturing capacity and …