scholarly journals URANS studies of hydrodynamic performance and slamming loads on high-speed planing hulls in calm water and waves for deep and shallow conditions

2015 ◽  
Vol 51 ◽  
pp. 222-240 ◽  
Author(s):  
S. Maysam Mousaviraad ◽  
Zhaoyuan Wang ◽  
Frederick Stern
Keyword(s):  
High Speed ◽  
Hydrodynamic Performance ◽  
Calm Water

Experimental appraisal of hydrodynamic performance and motion of a single-stepped high-speed vessel in calm water and regular waves

2020 ◽  
pp. 095440622096812
Author(s):  
Sayyed Mahdi Sajedi ◽  
Parviz Ghadimi ◽  
Aliakbar Ghadimi ◽  
Mohammad Sheikholeslami
Keyword(s):  
High Speed ◽  
Single Step ◽  
Hydrodynamic Performance ◽  
Sea Waves ◽  
Regular Waves ◽  
Height Range ◽  
Step Model ◽  
Speed Range ◽  
Calm Water ◽  
Laboratory Models

High-speed vessels exhibit various motions and accelerations in calm water and sea waves. For examining the behavior of high-speed vessels, it is possible to examine these movements in laboratory models. In this paper, a single-step model in calm water is experimentally tested and compared with a model of no step. The speed range of these vessels is 1 m/s to 9 m/s equivalent to Beam Froude numbers of 0.43 to 3.87. During these experiments, the resistance parameters, trim, bow, and stern rise-up as well as the center of the gravity are measured. The non-step model has longitudinal instability at a speed of 8 m/s. This instability is avoided when the vessel is equipped by a transversal step. The vessel's trim and resistance are also reduced in the planing mode in calm water. Subsequently, hydrodynamic performance and its seakeeping condition in the planing regime are investigated for both vessels in regular waves. The single-step and non-step vessels are tested in the wavelength range of [Formula: see text], and the wave height range of 6 to 18 centimeters. It is observed that stepped vessel experiences lower motions and bow accelerations and less added resistance in comparison to the non-stepped vessel.

Comparative Performance of Optimum High Speed SWATH and Semi-SWATH in Calm Water and in Waves

2015 ◽  
Author(s):  
S. Brizzolara ◽  
G. Vernengo ◽  
L. Bonfiglio ◽  
D. Bruzzone
Keyword(s):  
High Speed ◽  
Hydrodynamic Performance ◽  
Forward Speed ◽  
Comparative Performance ◽  
Hull Form ◽  
High Speeds ◽  
Head Waves ◽  
Calm Water ◽  
Minimization Algorithms ◽  
Ranse Solver

The hydrodynamic performance of unconventional SWATH and Semi-SWATH for high speed applications are analyzed and compared in this paper. Bare hull resistance in calm water is estimated by an inviscid boundary element method with viscous corrections and verified by a fully turbulent, multiphase unsteady RANSE solver. Motions response in head waves, calculated by a frequency domain 3D panel method with forward speed effects are also evaluated and compared. Both considered hulls are the best designs coming from full parametric hull form optimization procedures, based on CFD solvers for the estimation of their hydrodynamic performance and driven by evolutionary minimization algorithms. The SWATH has twin parabolic struts and an unconventional underwater shape, the semi-SWATH has a slender triangular waterline, a bulbous shape in the entrance body which gradually morph into a U-section with a shallow transom in the run body. In general, as expected, the Semi-SWATH hull shows a lower drag at high speeds while the single strut SWATH is superior at lower speeds. As regards seakeeping, the SWATH shows unbeatable lower pitch and heave motions in shorter waves, where the Semi-SWATH evidences a double peaked RAO. More detailed analysis and conclusion are drawn in the paper.

scholarly journals An experimental study of interceptor’s effectiveness on hydrodynamic performance of high-speed planing crafts

2013 ◽  
Vol 20 (2) ◽  
pp. 21-29 ◽  
Author(s):  
Mohammad Hosein Karimi ◽  
Mohammad Saeed Seif ◽  
Madjid Abbaspoor
Keyword(s):  
Drag Reduction ◽  
High Speed ◽  
Hydrodynamic Performance ◽  
Control Mechanisms ◽  
Towing Tank ◽  
University Of Technology ◽  
Speed Range ◽  
Calm Water ◽  
Wide Speed Range ◽  
The Impact

Abstract Trim control mechanisms such as interceptors and trim flaps have been widely used in recent years in highspeed crafts for ride and trim control. In spite of their extensive application, a few studies investigating the impact of interceptors on planing craft performance, have been published. In the present study, the impact of interceptors on planing crafts hydrodynamic quality is investigated through application of an experimental method. Two scaled-down models of high-speed planing mono-hull and catamaran are tested with and without interceptors in calm water at different heights of the interceptors to investigate the effect of interceptors on drag reduction of the models. The first one is a scaled-down model of 11 m planing mono-hull boat and the test was conducted at the towing tank of Sharif University of Technology, Iran. The second one is a scaled-down model of 18 m planing catamaran boat and the test was conducted at the towing tank of Krylov Shipbuilding Research Institute (KSRI), Russia. The experimental results show a remarkable drag reduction of up to 15% for mono-hull model and up to 12% for catamaran model over the wide speed range of the models.

scholarly journals Numerical Study of Hydrodynamics of Heavily Loaded Hard-Chine Hulls in Calm Water

2021 ◽  
Vol 9 (2) ◽  
pp. 184
Author(s):  
Miles P. Wheeler ◽  
Konstantin I. Matveev ◽  
Tao Xing
Keyword(s):  
High Speed ◽  
Numerical Study ◽  
The Other ◽  
Hydrodynamic Performance ◽  
Pressure Distributions ◽  
Wave Patterns ◽  
Speed Range ◽  
Calm Water ◽  
Program Star ◽  
Displacement Regime

Hard-chine boats are usually intended for high-speed regimes where they operate in the planing mode. These boats are often designed to be relatively light, but there are special applications that may occasionally require fast boats to be heavily loaded. In this study, steady-state hydrodynamic performance of nominal-weight and overloaded hard-chine hulls in calm water is investigated with computational fluid dynamics solver program STAR-CCM+. The resistance and attitude values of a constant-deadrise reference hull and its modifications with more pronounced bows of concave and convex shapes are obtained from numerical simulations. On average, 40% heavier hulls showed about 30% larger drag over the speed range from the displacement to planing modes. Among the studied configurations, the hull with a concave bow is found to have 5–12% lower resistance than the other hulls in the semi-displacement regime and heavy loadings and 2–10% lower drag in the displacement regime and nominal loading, while this hull is also capable of achieving fast planing speeds at the nominal weight with typical available thrust. The near-hull wave patterns and hull pressure distributions for selected conditions are presented and discussed as well.

Numerical Study on the Effect of Stern Flap for Hydrodynamic Performance of Catamaran

2019 ◽  
Author(s):  
Peng Zhou ◽  
Liwei Liu ◽  
Lixiang Guo ◽  
Qing Wang ◽  
Xianzhou Wang
Keyword(s):  
High Speed ◽  
Cfd Simulation ◽  
Numerical Study ◽  
Experimental Studies ◽  
Hydrodynamic Performance ◽  
Flow Solver ◽  
Calm Water ◽  
Unsteady Simulation ◽  
Ship Hydrodynamic ◽  
Simulation Results

Abstract This paper presents CFD simulation results of the stern flap effect with different lengths for hydrodynamic performance of catamaran moving in calm water, including resistance and sailing attitude. Inhouse viscous CFD (computational fluid dynamics) code HUST-Ship (Hydrodynamic Unsteady Simulation Technology for Ship) is used for the study. The catamaran with/without stern flap with different lengths were studied. The trim and sinkage of the catamaran were solved coupled with flow solver. Experimental studies in calm water were conducted to validate the numerical method. The comparison of hydrodynamic performance of catamaran with stern flaps of different lengths was made. The results show that the stern flap can reduce the sailing attitude and has influence for the resistance of catamaran at high-speed.

Numerical Simulation of Hydrodynamic Performance of Multi-Hull Catamaran With 3DOF Motion

2018 ◽  
Author(s):  
Rijie Li ◽  
Liwei Liu ◽  
Lixiang Guo ◽  
Dakui Feng ◽  
Xianzhou Wang
Keyword(s):  
Fluid Dynamics ◽  
High Speed ◽  
Degrees Of Freedom ◽  
Turbulence Models ◽  
Body Motion ◽  
Hydrodynamic Performance ◽  
Experimental Fluid Dynamics ◽  
Calm Water ◽  
Sinkage And Trim ◽  
Resistance Prediction

This paper presents CFD to study the hydrodynamic performance for the high-speed, multi-hull Catamaran advancing in calm water. It uses inhouse computational fluid dynamics (CFD) code to solve RANS equation coupled with six degrees of freedom solid body motion equations. RANS equations are solved by finite difference method and PISO arithmetic. Computations have been made using structured grid with overset technology. Turbulence models used the anisotropic two equations Shear Stress Transport (SST) k-ω model. Single phase level set was used for free surface simulation. A good agreement on the resistance prediction between CFD and experimental fluid dynamics (EFD) has been observed (on the resistance prediction of about 4.0%). Differences between CFD and EFD have been seen for the 3 degrees of freedom (3DOF) motion, whereas larger discrepancy is observed for the sinkage and trim estimation (about 8.0%).

A Proposal for Performance Criteria for Propulsion Losses Due to Ship Steering

1982 ◽  
Vol 104 (2) ◽  
pp. 158-165 ◽  
Author(s):  
R. E. Reid
Keyword(s):  
High Speed ◽  
Operating Conditions ◽  
Relative Performance ◽  
Performance Criteria ◽  
Ship Steering ◽  
Calm Water ◽  
Simulation Results ◽  
Definition Of ◽  
Hydrodynamic Data

The problem of definition of propulsion loss related to ship steering is addressed. Performance criteria representative of propulsion losses due to steering over a range of operating conditions including operation in calm water and a seaway are considered. Criteria are derived from strict analytical considerations and from empirical assumptions based on experimentally derived hydrodynamic data. The applicability of these various criteria and the implications for both assessment of relative performance of existing ship autopilots and for the design of new steering controllers is discussed in relation to simulation results for a high-speed containership.

An Analysis of Heave Added Mass and Damping of a Surface-Effect Ship

1981 ◽  
Vol 25 (01) ◽  
pp. 44-61
Author(s):  
C. H. Kim ◽  
S. Tsakonas
Keyword(s):  
Free Surface ◽  
High Speed ◽  
Surface Effect ◽  
Practical Method ◽  
Added Mass ◽  
Damping Coefficients ◽  
Calm Water ◽  
Surface Effect Ship ◽  
Long Time ◽  
Computational Procedures

The analysis presents a practical method for evaluating the added-mass and damping coefficients of a heaving surface-effect ship in uniform translation. The theoretical added-mass and damping coefficients and the heave response show fair agreement with the corresponding experimental values. Comparisons of the coupled aero-hydrodynamic and uncoupled analytical results with the experimental data prove that the uncoupled theory, dominant for a long time, that neglects the free-surface effects is an oversimplified procedure. The analysis also provides means of estimating the wave elevation of the free surface, the escape area at the stern and the volume which are induced by a heaving surface-effect ship in uniform translation in otherwise calm water. Computational procedures have been programmed in the FORTRAN IV language and adapted to the PDP-10 high-speed digital computer.

scholarly journals Numerical Analysis on the Effect of Artificial Ventilated Pipe Diameter on Hydrodynamic Performance of a Surface-Piercing Propeller

2019 ◽  
Vol 7 (8) ◽  
pp. 240
Author(s):  
Gao ◽  
Yang ◽  
Li ◽  
Dong
Keyword(s):  
High Speed ◽  
Water Immersion ◽  
Active Role ◽  
Numerical Results ◽  
Hydrodynamic Performance ◽  
Pipe Diameter ◽  
Pressure Area ◽  
Cfd Method ◽  
Thrust And Torque ◽  
Surface Piercing Propeller

Under the condition of large water immersion, surface-piercing propellers are inclined to be heavy loaded. In order to improve the hydrodynamic performance of the surface-piercing propeller, the installation of a vent pipe in front of a propeller disc is more widely used in the propulsion device of high speed planning crafts. Based on computational fluid dynamics (CFD) method, this paper studied the influence of diverse vent pipe diameters on hydrodynamic performance of the surface-piercing propeller under full water immersion conditions. The numerical results show that, with the increase of vent pipe diameters, the thrust and torque of the surface-piercing propeller decrease after ventilation, and the efficiency of the propeller increases rapidly; the low pressure area near the back root of the blade becomes smaller and smaller gradually; and the peak of periodic vibration of thrust and torque can be effectively reduced. The numerical results demonstrate that the installation of artificial vent pipe effectively improves the hydrodynamic performance of surface piercing propeller in the field of high speed crafts, and the increase of artificial vent pipe diameter plays an active role in the propulsion efficiency of the surface-piercing propeller.

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