scholarly journals Analysis of Effect of Bulbous Bow Shape to Ship Resistance in Catamaran Boat

2018 ◽  
Vol 159 ◽  
pp. 02058
Author(s):  
Deddy Chrismianto ◽  
Kiryanto ◽  
Berlian Arswendo Adietya
Keyword(s):  
Fluid Dynamic ◽  
The Body ◽  
Wave System ◽  
Total Resistance ◽  
Factors Affecting ◽  
Ship Resistance ◽  
Bow Wave ◽  
Main Factors ◽  
The One ◽  
Bulbous Bow

Ship resistance is one of the main factors affecting the design of a ship. Catamaran boat is a ship with small wet surface area that able to reduce drag and improve ship power. Generally, a bulbous bow is implemented to reduce wave resistance because the bulbous shape is believed to attenuate the bow wave system. Additionally, the bulbous bow also tends to reduce viscous resistance. When the flow around the body is smooth, the total ship resistance can be reduced significantly if the optimum bulbous bow is obtained. In this study, the main purpose is to get the bulbous bow shape in catamaran boat which produces the smallest ship resistance by using computational fluid dynamic (CFD). Generating the variation of the bulbous bow shapes apply the one-to-one correspondence of the cross section parameter (ABT) and lateral parameter (ABL). The result of investigation shows that application of bulbous bow on catamaran boat can reduce about 11-13% of total resistance of ship.

THE STUDY OF THE UNSTEADY FLUID-DYNAMIC FORCES ACTING ON AN AUTO ROTATING ELLIPTIC CYLINDER

2005 ◽  
Vol 19 (28n29) ◽  
pp. 1675-1678
Author(s):  
TAKAHIRO YASUDA ◽  
YASUNARI TAKANO
Keyword(s):  
Fluid Dynamic ◽  
Elliptic Cylinder ◽  
The Body ◽  
High Lift ◽  
Dynamic Forces ◽  
Zero Degree ◽  
Unsteady Fluid ◽  
Complex Velocity Potential ◽  
The One ◽  
Cylinder Rotation

When a thin flat pate is released in the still air, the plate may fall aslant and automatically set into a rotational motion. This phenomenon is called autorotation. In this state, the unsteady fluid-dynamic forces act on the plate due to the vortex shedding and the rotation of the body. In this study, we focused on the auto-rotating phenomenon of an elliptic cylinder and investigated the effect of the cylinder rotation on the unsteady fluid-dynamic forces by the comparison between the result of the complex velocity potential theory and the one of numerical simulation. It was found that the low drag occurring at -160 degree phase and the high lift at zero degree phase are caused by the cylinder rotation.

scholarly journals ANALYSIS OF BULBOUS BOW RESISTANCE WITH DIMPLE (BASIN) ON KRI CLASS STRATEGIC SEALIFT VESSEL (SSV) USING CFD SOFTWARE

JOURNAL ASRO ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 123
Author(s):  
Dwi Putra Maulana ◽  
Irfan Syarif Arief ◽  
Cahya Kusuma ◽  
Wawan Kusdiana ◽  
Mohammad Syaifi
Keyword(s):  
Surface Area ◽  
Final Conclusion ◽  
Total Resistance ◽  
Reduce Fuel Consumption ◽  
Friction Resistance ◽  
Ship Resistance ◽  
Cfd Applications ◽  
Bulbous Bow ◽  
Resistance Value

The function and role of the Strategic Sealift Vessel (SSV) ship type is very important. Modifications andchanges to improve the value of efficiency will be very necessary. This efficiency value is closely related to thevalue of Ship Resistance , where if the Resistance value goes down, the value of the ship's efficiency will rise.The increase in efficiency is then expected to reduce fuel consumption and increase speed. In several studies,ways have been improved to improve the condition, one of them is by adding a Dimple to the Surface Area ofthe ship, this modification will reduce the friction Resistance that the ship will receive by reducing the WettedSurface Area that the fluid will pass at certain speeds and conditions. . This modification will be applied to theship's Bulbous Bow section. In this way it is expected to improve the value of the Resistance produced by theBulbous Bow installed in the ship, without having to carry out significant changes or modifications and changethe shipbuilding of the existing Linesplane. Furthermore, the analysis is carried out by modeling using 2D and3D CAD Software and Model Experiments using CFD Applications. After carrying out the entire process ofRunning with the CFD Software to determine the value of the Ship Resistance . The final conclusion is in theform a reduction the value of vessel Total Resistance the Running Bow section of 31.53% in the 4th variationsand Fn used is 0,341.Keywords: Boulbous Bow, CFD, Dimple, Reduction, Resistance

E-Procurement

2013 ◽  
pp. 87-113
Author(s):  
Davide Aloini ◽  
Riccardo Dulmin ◽  
Valeria Mininno
Keyword(s):  
Empirical Work ◽  
The Body ◽  
Critical Factors ◽  
Factors Affecting ◽  
Final Performance ◽  
Body Of Knowledge ◽  
Main Factors ◽  
Business To Business ◽  
A Current ◽  
Explorative Factor Analysis

Although the implementation of e-auction events is not all that new, a current interest in understanding main issues involved in its implementation exists, especially in a business to business (B2B) environment. A clear will to classify and systematize the numerous variables directly or indirectly affecting e-auction suitability and final performance determination is evident also from previous conceptual literature contributions. Nevertheless a lack of empirical work in this field is evident. This work provides a contribution to the body of knowledge on critical factors impacting on e-Reverse Auctions (e-RA) performance in a B2B context. Based on an explorative factor analysis addressed to a panel of academic experts and practitioners, it aims at identifying the main factors affecting price and process performance in B2B e-RA.

scholarly journals Ecological determinants of the development of coal mining enterprises in the russian federation

2021 ◽  
Vol 303 ◽  
pp. 01010
Author(s):  
Svetlana Grigashkina ◽  
Irina Verchagina ◽  
Irina Kolechkina
Keyword(s):  
Coal Mining ◽  
Fossil Fuels ◽  
Factors Affecting ◽  
Legal Norms ◽  
Economic Issues ◽  
Mining Companies ◽  
The Russian Federation ◽  
Main Factors ◽  
The One ◽  
Mining Regions

The work is devoted to the study of the external aspects of the functioning of modern coal mining enterprises in Russia. Particular attention is paid to foreign economic issues and regional risks of the development of the organization associated with environmental activities. Trends in the development of international legal norms, which, on the one hand, are aimed at protecting sustainable environmental development, and on the other hand, may hinder international trade in hydrocarbons and fossil fuels, as well as their consumption, are considered as the main factors affecting coal mining companies. The issues of regional development of coal-mining regions in the light of solving environmental problems were also considered.

Study on the Functional Orientation of the Urban Complex

2014 ◽  
Vol 488-489 ◽  
pp. 449-452
Author(s):  
Chao Zhou
Keyword(s):  
Functional Analysis ◽  
The Other ◽  
Theoretical Argument ◽  
Factors Affecting ◽  
Functional Orientation ◽  
Urban Problems ◽  
Main Factors ◽  
Urban Complex ◽  
The One ◽  
The City

Accelerated the development of urbanization, on the one hand, it requires urban complex implementing its overall function to deal with urban problems; on the other hand, requires urban complex requirements urban complex with living services and production services internal functions of the organic integration. To solve this problem, through the city complex functional analysis this chapter summarizes the main factors affecting functional orientation, presents the basis for functional orientation, methods and procedures, that can provide a theoretical argument for the urban complex functional.

Development and Research FMEA Expert Team Model

2020 ◽  
Vol 27 (05) ◽  
pp. 2040015 ◽  
Author(s):  
D. Panyukov ◽  
V. Kozlovsky ◽  
Y. Klochkov
Keyword(s):  
Initial Conditions ◽  
Preliminary Assessment ◽  
Factors Affecting ◽  
Expert Team ◽  
Main Factors ◽  
Fmea Method ◽  
The One ◽  
Team Model ◽  
Simultaneous Change ◽  
Over Time

This paper presents a description and research of the model of the team of experts in the application of the Failure Mode and Effects Analysis (FMEA). The main factors affecting the efficiency of the team of experts are highlighted. The generalized mathematical model of influence of these factors on efficiency of work of team is described. The research of this model on three different sets of initial data characterizing typical situations arising at the enterprise at application of the FMEA method is presented. An assessment was made of the simultaneous change of two types of competencies and motivation of both the participants and the team-wide single parameter. The model is studied on three typical situations with a different set of initial conditions and the corresponding parameters. The use of this technique allows for a preliminary assessment of the change in the effectiveness of the analysis by a team of specialists over time, which allows on the one hand to plan correctly not only the application of the FMEA itself within the overall schedule of work, but also to properly organize the training of the team. In addition, this technique will allow you to visually compare the various teams with each other and choose the most optimal or effective team.

scholarly journals Bulbous bow applications on a catamaran fishing vessel for improving performance

2018 ◽  
Vol 159 ◽  
pp. 02057 ◽  
Author(s):  
Samuel ◽  
Dong-Joon Kim ◽  
Muhammad Iqbal ◽  
Aldias Bahatmaka ◽  
Aditya Rio Prabowo
Keyword(s):  
Finite Element Method ◽  
Fluid Dynamic ◽  
Wave Resistance ◽  
Total Resistance ◽  
Fishing Vessel ◽  
Dynamic Approach ◽  
Slender Body Theory ◽  
Vessel Resistance ◽  
Bulbous Bow ◽  
Body Theory

This study aims to prove the usefulness of a bulbous bow traditional catamaran fishing vessel. Bulbous bow applications are widely used to reduce wave resistance. The fishing vessel resistance was calculated using CFD (Computational Fluid Dynamic) approach and combined with classical slender body theory. In this research, the application of bulbous bow was being adopted on traditional catamaran fishing vessel to reduce the total resistance. The bulbous bow has adopted based on Kracht method. Modeling procedure was developed by using linear form coefficients. The ship resistance was simulated using Tdyn software which basically Finite Element Method. The results show that adding bulbous bow can decrease or increase the ship’s total resistance.

scholarly journals Forest soil acidification in the Czech Republic

2006 ◽  
Vol 52 (Special Issue) ◽  
pp. S14-S22 ◽  
Author(s):  
E. Klimo ◽  
J. Materna ◽  
V. Lochman ◽  
J. Kulhavý
Keyword(s):  
Czech Republic ◽  
Forest Soils ◽  
The Other ◽  
Forest Stands ◽  
The Czech Republic ◽  
Factors Affecting ◽  
Natural Factors ◽  
Main Factors ◽  
The One ◽  
Properties Of Soil

Damage to forest stands and their decline in the Czech Republic evoked a necessity to elucidate the function of soil in these processes. Main factors affecting acidification of forest soils are assessed in the paper. On the one hand, it refers to natural factors such as properties of soil-forming substrates and species composition of forest stands, on the other hand, to the effects of anthropogenic character such as influences of man-made spruce monocultures and effects of acid depositions. Special attention is paid to the development of forest soils in the Krušné hory Mts., where the effects of acid depositions are highest.

Study on Influencing Factors of the Seaming of Knitted and Woven Fabrics

2011 ◽  
Vol 291-294 ◽  
pp. 689-692
Author(s):  
Bin Lin ◽  
Zhe Li
Keyword(s):  
Breaking Strength ◽  
Woven Fabrics ◽  
Test Results ◽  
Knitted Fabrics ◽  
Elongation At Break ◽  
Factors Affecting ◽  
Stitch Density ◽  
Main Factors ◽  
The One ◽  
Joint Method

Clothing combining knitted and woven fabrics gets more and more favor of people. In this study, three knitted fabrics and three woven fabrics which are common on market were selected and seamed. The tensile breaking strength, elongation at break and the fracture reason of the joint of knitted and woven fabrics were tested using the one-way vertically stretching method. The test results were analyzed and it was found there are many factors affecting the seam strength of knitted and woven fabrics. Experiment shows that the main factors include: stitch density, joint method and choice of the joining material. The study of this subject provides the basis for designing better joint wear and improving sewing quality and efficiency.

Nonlinear free-surface flow at a two-dimensional bow

1989 ◽  
Vol 209 ◽  
pp. 57-75 ◽  
Author(s):  
Mark A. Grosenbaugh ◽  
Ronald W. Yeung
Keyword(s):  
Free Surface ◽  
Froude Number ◽  
Stagnation Point ◽  
Free Surface Flow ◽  
Surface Flow ◽  
The Body ◽  
Two Dimensional ◽  
Bow Wave ◽  
Bulbous Bow ◽  
Nonlinear Free Surface

Unsteady free-surface flow at the bow of a steadily moving, two-dimensional body is solved using a modified Eulerian-Lagrangian technique. Lagrangian marker particles are distributed on both the free surface and the far-field boundary. The flow field corresponding to an inviscid, double-body solution is used for the initial condition. Solutions are obtained over a range of Froude numbers for bodies of three different shapes: a vertical step, a faired profile, and a bulbous bow. A transition Froude number exists at which the bow wave begins to overturn and break. The value of the transition Froude number depends on the bow shape. A stagnation point is observed to be present below the free surface during the initial stage of the wave formation. For flows occurring above the transition Froude number, the stagnation point remains trapped below the free surface as the wave overturns. Below the transition Froude number, the stagnation point rises to the surface as the crest of the transient bow wave moves upstream and away from the body.

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