Effect of Container Stack Arrangements on the Power Optimization of a Container Ship

2012 ◽  
Vol 28 (01) ◽  
pp. 10-19
Author(s):  
Khairul Hassan ◽  
Maurice F. White ◽  
Cosmin Ciorta
Keyword(s):  
High Speed ◽  
Flow Direction ◽  
Fluid Dynamic ◽  
Aerodynamic Resistance ◽  
Computational Fluid Dynamic Simulation ◽  
Design Tool ◽  
Optimal Arrangement ◽  
Power Requirement ◽  
Air Resistance ◽  
Propulsion Power

When considering the design of a ship, an important objective is to always try and develop one that allows for maximum cargo capacity with the lowest propulsion power requirement while providing a sufficient amount of strength and stability for its safe operation. The ship with the lowest propulsion power consumes the least amount of fuel and produces the lowest amount of exhaust gas that may be harmful to the environment. In some cases, the aerodynamic resistance can be neglected, but for a high speed vessel such as a modern containership, the air resistance can be in the range of 2% to 10% of the total resistance. Aerodynamic resistance can therefore have a significant effect on power requirements and is strongly influenced by the height, breadth, and the number of container stacks on the deck. The freeboard, beam of the ship, deck house design, ship speed, wind speed, and water flow direction will also contribute significantly to a ship's resistance and required propulsive power. This paper outlines the application of computational fluid dynamic simulation as a design tool to find a strategy for the optimal arrangement of the container stacks on deck so that the vessel uses the lowest effective propulsion power to achieve a fuel efficient ship. It is deduced that an optimal stack arrangement can reduce air resistance by about 30%.

Design and Simulation of a Novel High-Speed Omnidirectional Fully-Actuated Underwater Propulsion Mechanism

2019 ◽  
Author(s):  
Taylor Njaka ◽  
Stefano Brizzolara ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Response Time ◽  
High Speed ◽  
Position Control ◽  
Mechanical Design ◽  
Flow Direction ◽  
Fluid Dynamic ◽  
Coordinate Frame ◽  
Roll Control ◽  
Turbulent Environments ◽  
Underwater Propulsion

Abstract This paper details the design and simulation of a novel position control mechanism for marine operations or inspection in extreme, hostile, or high-speed turbulent environments where unprecedented speed and agility are necessary. The omnidirectional mechanism consists of a set of counter-rotating blades operating at frequencies high enough to dampen vibrational effects on onboard sensors. Each rotor is individually powered to allow for roll control via relative motor effort and attached to a servo-swashplate mechanism, enabling quick and powerful manipulation of fluid flow direction in a hull’s coordinate frame without the need to track rotor position. The mechanism inherently severs blade loads from servo torques, putting all load on the main motors and minimizing servo response time, while exploiting consistent blade momentum to minimize the corresponding force response time. The mechanical design and kinematic analysis of each subsystem is presented, followed by kinematic and hydrodynamic analysis of the hull and surrounding fluid forces during various blade maneuvers. Special maneuvers are verified using Computational Fluid Dynamic (CFD) software. Finally, a controller is constructed with decoupled parameters for each degree of freedom.

Computational Analyses of an In-Vitro Aneurysm Model Based on Three-Dimensional Angiography With Comparison to Phase Contrast Magnetic Resonance Imaging and Dye Injection Studies

2010 ◽  
Author(s):  
Stephanie M. George ◽  
Pierre Watson ◽  
John N. Oshinski ◽  
Charles W. Kerber ◽  
Daniel Karolyi ◽  
...  
Keyword(s):  
High Speed ◽  
Phase Contrast ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Cerebral Aneurysms ◽  
Computational Fluid Dynamic Simulation ◽  
Poor Correlation ◽  
Aneurysm Model

Computational fluid dynamic simulation (CFD) is a valuable tool that has been used to understand some of the fundamental conditions of cerebrovascular flow. Current methods include anatomic modeling of cerebral aneurysms derived from vascular imaging such as MRA, CTA, and three-dimensional angiography. The input blood flow waveforms can be represented from either mathematical models or physiologic sampling of flow with phase contrast MR techniques or particle image velocimetry (1). While there has been general acceptance of the validity of computational fluid dynamics, some research suggests that there can be poor correlation between CFD flow calculations and directly measured flow (2). Therefore, the purpose of this study is to qualitatively compare flow patterns in a cerebral aneurysm model using data derived from three sources: (i) direct phase contrast MRA measurement in the model; (ii) CFD simulation using computer models created from three dimensional angiography, and (iii) previously published high speed injection dye studies.

scholarly journals Analysis of the Effect of Inlet Velocity on Cooling Speed in a Refrigerated Container using CFD simulations

CFD letters ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 55-62
Author(s):  
Muhammad Arif Budiyanto ◽  
Nadhilah Suheriyanto
Keyword(s):  
High Speed ◽  
Fluid Dynamic ◽  
Computational Fluid Dynamic Simulation ◽  
Cfd Simulations ◽  
Cooling Performance ◽  
Inlet Velocity ◽  
Low Speed ◽  
Perishable Goods ◽  
Cooling Speed ◽  
Fan Speed

The use of refrigerated containers continues to increase rapidly in line with global trade, this kind of container is commonly used to deliver perishable cargo from producers to consumers over great distances, even between continents. To avoid perishable goods from damages, the temperature inside refrigerated containers was controlled and maintained to keep the cooling performance. The purpose of this study is to investigate the effect of variation inlet velocity on the cooling speed inside a refrigerated container. This study was conducted through a computational fluid dynamic simulation validated with experimental results. The simulation was carried out on the variations of inlet velocity based on low-speed fan mode at 4 m/s equal to 32 circulations/hour, and high-speed fan mode at 10 m/s equal to 80 circulations/hour. The results of the simulation show that the greater the inlet fan speed, the faster the cooling speed. The finding of this study is the cooling speed time of high cube refrigerated container with the low-speed fan is 28 minutes and the high-speed fan is 40 minutes.

scholarly journals The effect of air flow on an aerodynamic device for a pantograph

2021 ◽  
Vol 2021 (4) ◽  
pp. 453-459
Author(s):  
A. A. Vorob’ev ◽  
◽  
Ya. S. Vatulin ◽  
D. D. Karimov ◽  
◽  
...  
Keyword(s):  
Energy Consumption ◽  
High Speed ◽  
Practical Importance ◽  
Aerodynamic Resistance ◽  
Rolling Stock ◽  
Current Collectors ◽  
Current Collection ◽  
Electric Rolling Stock ◽  
Air Resistance ◽  
High Speed Trains

Objective: To evaluate the infl uence of the parameters of current collectors of high-speed and very high-speed trains on the value of aerodynamic resistance. To study the effect of airfl ow on a pantograph aerodynamic device using SolidWorks software. Methods: A comparison of the obtained values of aerodynamic air resistance with those that were produced earlier is carried out. Results: By means of aerodynamic device, it is possible to reduce the speed of the air fl ow effecting the pantograph, to reduce the values of aerodynamic resistance and energy consumption, to extend the service life of current collectors. Practical importance: The proposed design can improve the current collection, which will reduce the load on the overhead line and the pantograph slide, and reduce the energy consumption of electric rolling stock.

Design and Implementation of an Efficient Parallel LFSR Architecture for Wireless Communication Systems

2019 ◽  
Vol 14 ◽  
Author(s):  
A. Suresh Babu ◽  
B. Anand
Keyword(s):  
Wireless Communication ◽  
Power Consumption ◽  
Low Power ◽  
Communication Systems ◽  
High Speed ◽  
Design Tool ◽  
Shift Register ◽  
Linear Feedback ◽  
Wireless Communication Systems ◽  
Coverage Area

: A Linear Feedback Shift Register (LFSR) considers a linear function typically an XOR operation of the previous state as an input to the current state. This paper describes in detail the recent Wireless Communication Systems (WCS) and techniques related to LFSR. Cryptographic methods and reconfigurable computing are two different applications used in the proposed shift register with improved speed and decreased power consumption. Comparing with the existing individual applications, the proposed shift register obtained >15 to <=45% of decreased power consumption with 30% of reduced coverage area. Hence this proposed low power high speed LFSR design suits for various low power high speed applications, for example wireless communication. The entire design architecture is simulated and verified in VHDL language. To synthesis a standard cell library of 0.7um CMOS is used. A custom design tool has been developed for measuring the power. From the results, it is obtained that the cryptographic efficiency is improved regarding time and complexity comparing with the existing algorithms. Hence, the proposed LFSR architecture can be used for any wireless applications due to parallel processing, multiple access and cryptographic methods.

scholarly journals Aerodynamic analysis of uphill drafting in cycling

2021 ◽  
Vol 24 (1) ◽  
Author(s):  
T. van Druenen ◽  
B. Blocken
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Scientific Literature ◽  
Sensitivity Analyses ◽  
Air Resistance ◽  
Wind Tunnel Measurements ◽  
Aerodynamic Effect ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

AbstractSome teams aiming for victory in a mountain stage in cycling take control in the uphill sections of the stage. While drafting, the team imposes a high speed at the front of the peloton defending their team leader from opponent’s attacks. Drafting is a well-known strategy on flat or descending sections and has been studied before in this context. However, there are no systematic and extensive studies in the scientific literature on the aerodynamic effect of uphill drafting. Some studies even suggested that for gradients above 7.2% the speeds drop to 17 km/h and the air resistance can be neglected. In this paper, uphill drafting is analyzed and quantified by means of drag reductions and power reductions obtained by computational fluid dynamics simulations validated with wind tunnel measurements. It is shown that even for gradients above 7.2%, drafting can yield substantial benefits. Drafting allows cyclists to save over 7% of power on a slope of 7.5% at a speed of 6 m/s. At a speed of 8 m/s, this reduction can exceed 16%. Sensitivity analyses indicate that significant power savings can be achieved, also with varying bicycle, cyclist, road and environmental characteristics.

scholarly journals Simulation of Hydraulic Cylinder Cushioning

2021 ◽  
Vol 13 (2) ◽  
pp. 494
Author(s):  
Antonio Algar ◽  
Javier Freire ◽  
Robert Castilla ◽  
Esteban Codina
Keyword(s):  
Dynamic Model ◽  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Computational Fluid Dynamic Simulation ◽  
Hydraulic Cylinder ◽  
Outlet Port ◽  
Optimal Behavior ◽  
Radial Movement ◽  
Mechanical Shocks ◽  
Radial Gap

The internal cushioning systems of hydraulic linear actuators avoid mechanical shocks at the end of their stroke. The design where the piston with perimeter grooves regulates the flow by standing in front of the outlet port has been investigated. First, a bond graph dynamic model has been developed, including the flow throughout the internal cushion design, characterized in detail by computational fluid-dynamic simulation. Following this, the radial movement of the piston and the fluid-dynamic coefficients, experimentally validated, are integrated into the dynamic model. The registered radial movement is in coherence with the significant drag force estimated in the CFD simulation, generated by the flow through the grooves, where the laminar flow regime predominates. Ultimately, the model aims to predict the behavior of the cushioning during the movement of the arm of an excavator. The analytical model developed predicts the performance of the cushioning system, in coherence with empirical results. There is an optimal behavior, highly influenced by the mechanical stress conditions of the system, subject to a compromise between an increasing section of the grooves and an optimization of the radial gap.

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