A Practical Method for the Prediction of Planing Craft Motions in Regular and Irregular Waves

2008 ◽  
Author(s):  
Luca Sebastiani ◽  
Dario Bruzzone ◽  
Paola Gualeni ◽  
Guido Rambaldi ◽  
Danilo Ruscelli ◽  
...  
Keyword(s):  
Performance Prediction ◽  
Practical Method ◽  
Added Mass ◽  
Hydrodynamic Performance ◽  
Irregular Waves ◽  
Design Tools ◽  
High Complexity ◽  
Hydrodynamic Problem ◽  
Planing Craft ◽  
Momentum Theory

Leisure boats market has constantly grown during the recent years, entailing an increasing need of design tools. This seems particularly urgent for seakeeping and hydrodynamic performance prediction in the field of planing boats. Numerical methodologies are almost consolidated instruments for conventional displacement ships, while some shortcomings are still to be faced and overcome concerning planing craft, due to the high complexity of the hydrodynamic problem. The present paper describes a simplified methodology for the prediction of pitch, heave and roll motions of a planing boat, in regular and irregular waves. In the formulation, a 2D approach is adopted, based on ‘momentum theory’; various aspects of the wedge-theory are used in order to model the sectional characteristics, with particular attention to the added mass. A validation of the proposed methodology concerning vertical motions is presented against data available in literature.

Hydrodynamic Performance Prediction of Stepped Planing Craft Using CFD and ANNs

2021 ◽  
Author(s):  
Hamid Kazemi ◽  
M. Mehdi Doustdar ◽  
Amin Najafi ◽  
Hashem Nowruzi ◽  
M. Javad Ameri
Keyword(s):  
Performance Prediction ◽  
Hydrodynamic Performance ◽  
Planing Craft

scholarly journals Aerodynamic analysis of multirotor vehicles using a higher-order potential flow method

2021 ◽  
Author(s):  
Devin F. Barcelos
Keyword(s):  
Performance Prediction ◽  
Potential Flow ◽  
Higher Order ◽  
Theory Approach ◽  
Blade Element Momentum Theory ◽  
Flow Method ◽  
Momentum Theory ◽  
Radial Loading ◽  
Rotational Direction ◽  
Blade Element

A higher-order potential flow method is adapted for the aerodynamic performance prediction of small rotors used in multirotor unmanned aerial vehicles. The method uses elements of distributed vorticity which results in numerical robustness with both a prescribed and relaxed wake representation. The radial loading and wake shapes of a rotor in hover were compared to experiment to show strong agreement for three disk loadings. The advancing flight performance prediction of a single rotor was compared to a single rotor was compared to a blade element momentum theory based approach and to experiment. Comparison showed good thrust and power agreement with experiment across a range of advance ratios and angles of attack. Prediction in descending flights showed improvements in comparison to the blade element momentum theory approach. The model was extended to a quadrotorm configuration showing the differences associated to vehicle orientation and rotor rotational direction.

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.

Experimental Study on Hydrodynamics of Hybrid Deep-V Monohull With Different Built-Up Appendages

2018 ◽  
Author(s):  
Shuzheng Sun ◽  
Hui Li ◽  
Muk Chen Ong
Keyword(s):  
Model Test ◽  
Performance Model ◽  
Hydrodynamic Performance ◽  
Irregular Waves ◽  
Hydrodynamic Characteristics ◽  
Vertical Acceleration ◽  
Test Results ◽  
Regular Waves ◽  
Sea State ◽  
Seakeeping Performance

The hydrodynamic characteristics of a hybrid deep-V monohull with different built-up appendages are investigated experimentally in order to improve the resistance and seakeeping performance. Model tests have been carried out to study the hydrodynamic performance between a bare deep-V vessel and a deep-V monohull with different built-up appendage configurations (i.e. a hybrid deep-V monohull). From the model test results, it is found that the existence of the appendages will reduce the amplitude of pitching angle and bow vertical acceleration compared to that of the bare deep-V vessel in heading regular waves. However, the resistances for the hybrid deep-V monohull with built-up appendages are increased 15.6% for Fn = 0.264, and 0.1% for Fn = 0.441 compared to the resistance of the bare deep-V vessel. The model test results of seakeeping performance in irregular waves show that the hybrid deep-V monohull gives a better seakeeping performance than the deep-V vessel. The pitching angle and bow vertical acceleration of the hybrid deep-V monohull containing a built-up appendage are reduced 15.3% and 20.6% compared to the deep-V monohull in irregular waves at Fn = 0.441 in 6th class sea state (H1/3 = 6m).

Hydrodynamic Performance of a Novel Free Surface Pitching Breakwater

2014 ◽  
Author(s):  
Vengatesan Venugopal ◽  
Stefan Zlatev
Keyword(s):  
Body Shape ◽  
Hydrodynamic Performance ◽  
Irregular Waves ◽  
Scale Model ◽  
Reflected Waves ◽  
Irregular Wave ◽  
Wave Flume ◽  
Floating Breakwater ◽  
Wave Heights ◽  
Transmission Ct

A new concept floating breakwater was developed and tested to evaluate its hydrodynamic performance in this paper. This innovative floating breakwater has a rocking body shape which could also be used as a wave power device. A scale model was tested in a wave flume under regular and irregular wave conditions for various combinations of wave frequencies and wave heights. The breakwater has been tested for three immersion depths of 0.05 m, 0.09 m and 0.13 m from still water level. The measured transmitted and reflected waves were used to evaluate the coefficients of transmission (CT), reflection (CR) and dissipation (CL). The results illustrated that the breakwater model performed at its best when submerged at 0.13m, as this immersion depth produced lower coefficients of transmission (CT), lower reflection coefficients (CR) and higher energy dissipation (CL) coefficients. The comparison between regular and irregular waves produced similar ranges of transmission, reflection and energy coefficients.

Numerical Simulation Calculation of Hydroplane Direct Route Motion Based on FLUENT

2012 ◽  
Vol 569 ◽  
pp. 368-375
Author(s):  
Yu Qin ◽  
Xiao Liang ◽  
Jia Ning Zhang
Keyword(s):  
Numerical Simulation ◽  
Performance Prediction ◽  
Dynamic Pressure ◽  
Hydrodynamic Performance ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Velocity Change ◽  
Direct Route ◽  
Field Situation ◽  
Simulation Calculation

Aiming at hydrodynamic performance prediction for hydroplane motion, numerical simulation calculation for direct route motion of a hydroplane was carried out under FLUENT software platform by using VOF method and RNG k-ε model and solving Navier-Stokes equation. Evolution of ship resistance was obtained as the velocity change, and flow field situation and dynamic pressure variation of hydroplane hull bottom were reflected intuitively. By comparing the results of FLUENT calculation and ship model experiment and theoretical estimation, analyzing, especially wake current, it was verified that numerical simulation calculation of hydroplane direct route motion and hydrodynamic performance prediction based on FLUENT are feasible and precise enough.

Unsteady Hydrodynamic Performance Prediction of Ducted Propeller Based on CFD

2013 ◽  
Vol 437 ◽  
pp. 32-35
Author(s):  
Li Jian Ou ◽  
Nan Huo Wu ◽  
De Yu Li
Keyword(s):  
Performance Prediction ◽  
Open Water ◽  
Hydrodynamic Performance ◽  
Moving Mesh Method ◽  
Ducted Propeller ◽  
Mesh Method ◽  
Bearing Force ◽  
Thrust And Torque ◽  
Wake Fields ◽  
Calculated Model

Firstly, the calculated model was created in UG and GAMBIT, and then the Moving Mesh method was adopted to simulate thrust and torque of ducted propeller using FLUENT in the open water. The thrust, torque and bearing force of ducted propeller in three different wake fields were calculated. And the influence on the performance of ducted propeller by the wake fields was analyzed.

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