scholarly journals A Scalable High-performance Topographic Flow Direction Algorithm for Hydrological Information Analysis

2016 ◽  
Author(s):  
Kornelijus Survila ◽  
Ahmet Artu Yιldιrιm ◽  
Ting Li ◽  
Yan Y. Liu ◽  
David G. Tarboton ◽  
...  
Keyword(s):  
High Performance ◽  
Flow Direction ◽  
Information Analysis ◽  
Flow Direction Algorithm

Characteristics of Inclined Fin-Tube Heat Exchanger for Compact Air Conditioner

2002 ◽  
Author(s):  
Haruaki Kanematsu ◽  
Kazuhiko Murakami
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
High Performance ◽  
Flow Direction ◽  
Numerical Approach ◽  
Air Conditioner ◽  
Large Space ◽  
Tube Heat Exchanger ◽  
Fin Tube ◽  
Inclined Angle

For saving space at an office or a clean room, it is needed to reduce the space of an air conditioner. It is effective to miniaturize a heat exchanger because it occupies the large space in the air conditioner. Three types of a heat exchanger that are an in-line tube and cut fins type, a staggered tube and cut fins type and a staggered tube and uncut fins type were investigated as four inclined angle tests of 0, 45, 60 and 80 degrees in a heat wind tunnel. The coefficients of flow friction and heat transfer rates were obtained from these experiments, and the characteristics of inclined heat exchanger were clarified by effects of tube arrangements, fin types and inclined angles against flow direction. As a numerical approach, two-dimensional steady models were applied on the staggered tube and the in-line tube by using BFC (Boundary-Fitted Coordinate Method); BFC is available to make grids for any install angle of the heat exchanger. The results of the numerical analysis visualized flow patterns and heat transfer in these heat exchangers. In case of 80-degrees angle, the flow makes dead area in a part of the heat exchanger, and it causes reducing performance of the heat exchanger. These results are available for improve a compact high performance heat exchanger.

A High Performance Low Pressure Ratio Turbine for Engine Electric Turbocompounding

2011 ◽  
Author(s):  
Aman M. I. Mamat ◽  
Muhamad H. Padzillah ◽  
Alessandro Romagnoli ◽  
Ricardo F. Martinez-Botas
Keyword(s):  
High Performance ◽  
Gasoline Engine ◽  
Flow Direction ◽  
Pressure Ratio ◽  
Design Procedure ◽  
Low Pressure ◽  
Operating Conditions ◽  
Exhaust Gases ◽  
Electric Generator ◽  
Turbine Design

In order to enhance energy extraction from the exhaust gases of a highly boosted downsized engine, an electric turbo-compounding unit can be fitted downstream of the main turbocharger. The extra energy made available to the vehicle can be used to feed batteries which can supply energy to electric units like superchargers, start and stop systems or other electric units. The current research focuses on the design of a turbine for a 1.0 litre gasoline engine which aims to reduce the CO2 emissions of a “cost-effective, ultra-efficient gasoline engine in small and large family car segment”. A 1-D engine simulation showed that a 3% improvement in brake specific fuel consumption (BSFC) can be expected with the use of an electric turbocompounding. However, the low pressure available to the exhaust gases expanded in the main turbocharger and the constant rotational speed required by the electric motor, motivated to design a new turbine which gives a high performance at lower pressures. Accordingly, a new turbine design was developed to recover energy of discharged exhaust gases at low pressure ratios (1.05–1.3) and to drive a small electric generator with a maximum power output of 1.0 kW. The design operating conditions were fixed at 50,000 rpm with a pressure ratio of 1.1. Commercially available turbines are not suitable for this purpose due to the very low efficiencies experienced when operating in these pressure ranges. The low pressure turbine design was carried out through a conventional non-dimensional mixed-flow turbine design method. The design procedure started with the establishment of 2-D configurations and was followed by the 3-D radial fibre blade design. A vane-less turbine volute was designed based on the knowledge of the rotor inlet flow direction and the magnitude of the absolute speed. The overall dimensions of the volute design were defined by the area-to-radius ratios at each respective volute circumferential azimuth angle. Subsequently, a comprehensive steady-state turbine performance analysis was performed by mean of Computational Fluid Dynamics (CFD) and it was found that a maximum of 76% of total-static efficiency ηt-s can be achieved at design speed.

scholarly journals Boxfish swimming paradox resolved: forces by the flow of water around the body promote manoeuvrability

2015 ◽  
Vol 12 (103) ◽  
pp. 20141146 ◽  
Author(s):  
S. Van Wassenbergh ◽  
K. van Manen ◽  
T. A. Marcroft ◽  
M. E. Alfaro ◽  
E. J. Stamhuis
Keyword(s):  
Drag Reduction ◽  
High Performance ◽  
Flow Direction ◽  
Current Theory ◽  
The Body ◽  
Hydrodynamic Drag ◽  
Aerodynamic Design ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

The shape of the carapace protecting the body of boxfishes has been attributed an important hydrodynamic role in drag reduction and in providing automatic, flow-direction realignment and is therefore used in bioinspired design of cars. However, tight swimming-course stabilization is paradoxical given the frequent, high-performance manoeuvring that boxfishes display in their spatially complex, coral reef territories. Here, by performing flow-tank measurements of hydrodynamic drag and yaw moments together with computational fluid dynamics simulations, we reverse several assumptions about the hydrodynamic role of the boxfish carapace. Firstly, despite serving as a model system in aerodynamic design, drag-reduction performance was relatively low compared with more generalized fish morphologies. Secondly, the current theory of course stabilization owing to flow over the boxfish carapace was rejected, as destabilizing moments were found consistently. This solves the boxfish swimming paradox: destabilizing moments enhance manoeuvrability, which is in accordance with the ecological demands for efficient turning and tilting.

Flow Direction Algorithm (FDA): a Novel Optimizer Approach for Solving Optimization Problems

2021 ◽  
pp. 107224
Author(s):  
Hojat Karami ◽  
Mahdi Valikhan Anaraki ◽  
Saeed Farzin ◽  
Seyedali mirjalili
Keyword(s):  
Optimization Problems ◽  
Flow Direction ◽  
Flow Direction Algorithm

A New Stretching Process: Slant Forging Method

2011 ◽  
Vol 181-182 ◽  
pp. 113-117
Author(s):  
Li Yong Ni ◽  
Suo Qing Yu ◽  
L. Li ◽  
S.Y. Zhu ◽  
Hua Gui Huang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
High Performance ◽  
Flow Direction ◽  
Metal Flow ◽  
Production Costs ◽  
Flow Lines ◽  
Forging Process ◽  
Stretching Process ◽  
Selection Of

High transversal properties requirements of heavy axial forgings, traditionally, often are met through the selection of high-performance materials, the improvement of metallurgical quality and repeated forging. But the production costs and power consumption are both high. A new slant forging method is adopted, by controlling the metal flow direction in forgings, to achieve the increase of transversal mechanical properties. Finite element method was applied to study the influence of forging process parameters on flow lines in axial forgings, providing theoretical guidance for the eventual realization of the forging method.

scholarly journals Parallelizing Multiple Flow Accumulation Algorithm using CUDA and OpenACC

2019 ◽  
Vol 8 (9) ◽  
pp. 386 ◽  
Author(s):  
Natalija Stojanovic ◽  
Dragan Stojanovic
Keyword(s):  
Energy Consumption ◽  
Graphics Processing Units ◽  
High Performance ◽  
Programming Model ◽  
Flow Direction ◽  
Computing Methods ◽  
Terrain Analysis ◽  
Central Processing ◽  
Watershed Analysis ◽  
Programming Effort

Watershed analysis, as a fundamental component of digital terrain analysis, is based on the Digital Elevation Model (DEM), which is a grid (raster) model of the Earth surface and topography. Watershed analysis consists of computationally and data intensive computing algorithms that need to be implemented by leveraging parallel and high-performance computing methods and techniques. In this paper, the Multiple Flow Direction (MFD) algorithm for watershed analysis is implemented and evaluated on multi-core Central Processing Units (CPU) and many-core Graphics Processing Units (GPU), which provides significant improvements in performance and energy usage. The implementation is based on NVIDIA CUDA (Compute Unified Device Architecture) implementation for GPU, as well as on OpenACC (Open ACCelerators), a parallel programming model, and a standard for parallel computing. Both phases of the MFD algorithm (i) iterative DEM preprocessing and (ii) iterative MFD algorithm, are parallelized and run over multi-core CPU and GPU. The evaluation of the proposed solutions is performed with respect to the execution time, energy consumption, and programming effort for algorithm parallelization for different sizes of input data. An experimental evaluation has shown not only the advantage of using OpenACC programming over CUDA programming in implementing the watershed analysis on a GPU in terms of performance, energy consumption, and programming effort, but also significant benefits in implementing it on the multi-core CPU.

scholarly journals Terrain Analysis for Locating Erosion Channels: Assessing LiDAR Data and Flow Direction Algorithm

10.5772/51526 ◽  
2012 ◽  
Author(s):  
Adam Pike ◽  
Tom Mueller ◽  
Eduardo Rienzi ◽  
Surendran Neelakantan ◽  
Blazan Mijatovic ◽  
...  
Keyword(s):  
Flow Direction ◽  
Lidar Data ◽  
Terrain Analysis ◽  
Flow Direction Algorithm

scholarly journals High-Performance of a Thick-Walled Polyamide Composite Produced by Microcellular Injection Molding

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4199
Author(s):  
Dariusz Sykutera ◽  
Piotr Czyżewski ◽  
Piotr Szewczykowski
Keyword(s):  
Injection Molding ◽  
High Performance ◽  
Flow Direction ◽  
Cell Diameter ◽  
Injection Molding Process ◽  
Polyamide 66 ◽  
Molding Process ◽  
Sem Images ◽  
Microcellular Injection Molding ◽  
Sink Mark

Lightweight moldings obtained by microcellular injection molding (MIM) are of great significance for saving materials and reducing energy consumption. For thick-walled parts, the standard injection molding process brings some defects, including a sink mark, warpage, and high shrinkage. Polyamide 66 (PA66)/glass fiber (GF) thick-walled moldings were prepared by MuCell® technology. The influences of moldings thickness (6 and 8.4 mm) and applied nitrogen pressure (16 and 20 MPa) on the morphology and mechanical properties were studied. Finally, the microcellular structure with a small cell diameter of about 30 μm was confirmed. Despite a significant time reduction of the holding phase (to 0.3 s), high-performance PA66 GF30 foamed moldings without sink marks and warpage were obtained. The excellent strength properties and favorable impact resistance while reducing the weight of thick-walled moldings were achieved. The main reason for the good results of polyamide composite was the orientation of the fibers in the flow direction and the large number of small nitrogen cells in the core and transition zone. The structure gradient was analysed and confirmed with scanning electron microscopy (SEM) images, X-ray micro computed tomography (micro CT) and finite element method (FEM) simulation.

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