Shallow Water Resistance Estimation for a Riverine Light Patrol Boat using Computational Fluid Dynamics (original) (raw)
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Behavior of ship changes drastically, when it moves from deep to shallow water. In the recent years much research is going on the ship hydrodynamics for practical navigation problems in getting ships safely into existing harbors. Investigation of ship behavior in restricted water depth may helpful during sea trials in speed reduction criteria where larger depth is not available near the coastline. The proper estimation of ship resistance and squat is influence largely on the power calculation in the design stage. The present work describes the effect of shallow water on the ship resistance at different speed using Computational Fluid Dynamics (CFD) techniques. A comparison in the drag on the hull is illustrated between depth restriction and infinite depth water. This paper provides a wide introduction into the problems of modeling of the restricted water depth effects on the ship behavior, specifically resistance using CFD.
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This research paper numerically investigated the hydrodynamic resistance of Multipurpose Amphibious Vehicles (MAV) navigating in shallow water. This type of vehicle and other coastal floating vehicles encounter the problem of a small under keel clearance with river bed. The proper estimation of ship resistance and squat is influenced largely on the power calculation in the design stage. The present work describes the effect of shallow water on the Multipurpose Amphibious Vehicles (MAV) resistance at different speeds using Computational Fluid Dynamics (CFD) techniques. A comparison in the drag on the hull is illustrated between depth restriction and infinite depth water. This paper provides a wide introduction into the problems of modeling the restricted water depth effects on the ship behaviour, specifically hydrodynamic resistance and squat using CFD as implemented by ANSYS-CFX14.0.
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On inland waterways the ship resistance and propulsive characteristics are strictly related to the depth of the waterway, thus it is important to have an understanding of the influence of water depth on ship hydrodynamic characteristics. Therefore, accurate predictions of hydrodynamic forces in restricted waterways are required and important. The aim of this paper is investigating the capability of the commercial unsteady Reynolds–Averaged Navier–Stokes (RANS) solver to predict the influence of water depth on ship resistance. The volume of fluid method (VOF) is applied to simulate the free surface flow around the ship. The hull resistance in shallow and deep water is compared. The obtained numerical results are validated against related experimental studies available in the literature.
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International Journal of Automotive and Mechanical Engineering, 2017
A reliable investigation that allows an accurate prediction of the total resistance coefficient of a high-speed" deep-V" catamaran in shallow water is obviously required. The Computational Fluid Dynamic simulation proposed approach is aimed to attain this precise outcome, while a hydrodynamic description of the rationale underlying behind the results is explained. Several effects of lateral separation ratios (S/L) and longitudinal staggered position (R/L) against a wide range of Froude numbers (Fr) from 0.5 to 1.0 were considered. The results revealed that the general increase in Fr is proportional to the increase of total resistance. In contrast, the increase of lateral separation ratios dealt with less total resistance coefficient, where the sufficient reduction of C T was about 11% as the Fr increase from 0.5 to 0.6 for S/L=0.3. Regardless of R/L ratios, the results showed the subsequent increase of Fr from 0.5 to 1.0 was also proportional to the total resistance, where the maximum increase of RT was about 21% as the Fr increase from 0.6 to 0.7. In addition, the increase of R/L ratios has led to sufficient increment of C T by 1.5% as the Fr increase from 0.9 to 1.0. Generally, the increase of S/L and R/L ratios have similar effects on the total resistance characteristics. This CFD simulation results are very useful as preliminary data for the ship resistance, which is mainly required for predicting a ship powering accurately.
Determining Ship Resistance Using Computational Fluid Dynamics (CFD)
The resistance of a hull is a consequence of force between air and water which act against the movement of ship or vessel. The ship resistance is an important issue for ensuring smooth propulsion. The traditional method to predict resistance on real hull is by using towing tank model running at corresponding Froude numbers, or called towing tank experiments. Disadvantages of this method are the associated cost and the limitation on the availability of physical tanks and models for every single design. These disadvantages can be overcome by using computational fluid dynamic, or numerical simulation. The objective of the study is to calculate the total resistance and simulate flow around Wigley and DTMB 5415 hull form using computational fluid dynamic. The result obtained from the numerical simulations were found almost similar with the experimental data. The highest percentage of error were only 5.94 percent for DTMB and 5.85 percent for Wigley hull. This result shows that the study ...
The objective of this paper is to investigate the hydrodynamic characteristics of high speed catamaran and trimaran ships at different speeds and finite depths using Computational Fluid Dynamics (CFD) techniques. Three dimensional Rankine Source Panel Method with non-linear free-surface boundary condition is used to capture free-surface potential flow around ship hull. Wave pattern, wave resistance, sinkage and trim for varying lateral and longitudinal separation of hull with varying water depths are determined and compared with each other to investigate spacing and depth effects on multihull ship. Computed results show a significant increase in total resistance for water of finite depth compared to deep water. A significant increase in sinkage and trim has also been found in the case of shallow water for both vessels.
An integrated method for predicting the hydrodynamic resistance of low- c B ships
Cad, 2010
An integrated CFD method is described for predicting the total hydrodynamic resistance at model as well as at full scale of conventional ship forms. The method combines a non-linear potential with a viscous flow solution of the RANS equations. The potential solution is achieved by covering the hull and the free surface with quadrilateral elements while convergence is based on an iterative procedure. A threeblock decomposition is introduced to solve the RANS equations in curvilinear coordinates and a new conformal mapping technique has been developed to generate grids effectively. To validate the method, experiments have been carried out for a model with three different bulbous bows at the towing tank of NTUA. Computed resistance coefficients for both the models and the 40:1 full scale ships are also compared in order to evaluate the fundamental principles of empirical extrapolation methods.
Design of Fast Patrol Boat for Improving Resistance, Stability, and Seakeeping Performance
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Indonesia is the largest archipelagic country and has the potential to become the world’s maritime axis. Two-thirds of Indonesia’s territory is ocean, with a total coastline of 54,716 km. Therefore, Indonesia must have solid systems and tools to overcome the various threats in the maritime sector. One of the technologies that can be developed to protect Indonesia’s naval territory is fast patrol boats. Indonesia requires efficient patrol boats that can optimally monitor the large Indonesian sea area and various potential threats in the maritime sector. Thus, research on the hydrodynamic criteria for the hull design of patrol boats is fundamental. In this study, we aimed to evaluate the design method based on hydrodynamic characteristics to obtain the primary dimensions and shape of the ship’s hull. We designed and analysed 11 ship models in terms of the following criteria: the resistance, stability, and seakeeping performance. The 11 models included five reference models of patrol b...