scholarly journals Hydro-Acoustic and Hydrodynamic Optimization of a Marine Propeller Using Genetic Algorithm, Boundary Element Method, and FW-H Equations

2019 ◽  
Vol 7 (9) ◽  
pp. 321 ◽  
Author(s):  
Abouzar Ebrahimi ◽  
Mohammad Saeed Seif ◽  
Ali Nouri-Borujerdi
Keyword(s):  
Genetic Algorithm ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Rake Angle ◽  
Geometric Optimization ◽  
Hydrodynamic Performance ◽  
Numerical Code ◽  
Skew Angle ◽  
Propeller Noise ◽  
Element Method

Noise generated by ships is one of the most significant noises in seas, and the propeller has a significant impact on the noise of ships, which reducing it can significantly lower the noise of vessels. In this study, a genetic algorithm was used to optimize the hydro-acoustic and hydrodynamic performance of propellers. The main objectives of this optimization were to reduce the propeller noise and increase its hydrodynamic efficiency. Modifying the propeller geometry is one of the most effective methods for optimizing a propeller performance. One of the numerical methods for calculating propeller noise is the Ffowcs Williams and Hawkings (FW-H) Model. A numerical code was developed by authors which solved these equations using the velocity and pressure distribution around the propeller and calculated its noise. To obtain flow quantities and to investigate the hydrodynamic performance of the propeller, a code was developed using a Boundary Element Method, the panel method. The geometry of DTMB 4119 propeller was selected for optimization, where geometric modifications included skew angle, rake angle, pitch to diameter (P/D) distribution, and chord to diameter (c/D) distribution. Finally, the results of geometric optimization were presented as Pareto optimal solutions. The results indicated that the optimum geometries had rake angles between 8.14 and 12.05 degrees and skew angles between 31.52 and 39.74 degrees. It was also observed that the increase in the chord up to a specific limit enhanced the efficiency and reduced the noise of the propeller.

scholarly journals EFFECT OF CONDUCTIVITY IN CORROSION PROBLEM USING BOUNDARY ELEMENT METHOD AND GENETIC ALGORITHM

2020 ◽  
Vol 1 (01) ◽  
pp. 58-63
Author(s):  
Mohammed Aldlemy
Keyword(s):  
Genetic Algorithm ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Potential Distribution ◽  
Electrical Potential ◽  
Matlab Program ◽  
Electrolyte Surface ◽  
Corrosion Problem ◽  
Indirect Analysis ◽  
Element Method

Boundary element method applications with inverse solution are used to apply the indirect analysis for modeling of corrosion problem. Laplace equation has been used to model the electrical potential in the electrolyte surface. In this paper a computer modeling has been developed to visualize the effect of conductivity value in corrosion problem. Genetic algorithm is used to create the conductivity value based on the mechanics of natural selection and genetics. The boundary element method is then calculating the potential value of the whole domain. FORTRAN and MATLAB program have been developed to calculate and visualize the potential distribution in the domain. Two-dimensional example problems are analyzed to demonstrate the application of the proposed boundary element modeling procedure.

A Comparison of Different Fluid-Structure Interaction Analysis Techniques for the Marine Propeller

2021 ◽  
Author(s):  
Wajiha Rehman ◽  
Stephane Paboeuf ◽  
Joseph Praful Tomy
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
Stokes Equations ◽  
Hydrodynamic Performance ◽  
Design Stage ◽  
Cooperative Research ◽  
Design Assessment ◽  
Fluid Structure ◽  
Marine Propellers ◽  
Element Method

Abstract The performance of the propeller is crucial to determine the energy-efficiency of a vessel. Fluid-Structure Interactions (FSI) analysis is one of the widely used methods to determine the hydrodynamic performance of marine propellers. This article is about the validation of a design assessment tool known as ComPropApp which is developed by Cooperative Research Ships (CRS) partners. ComPropApp is a specially designed tool for the FSI analysis of isotropic and composite marine propellers by doing explicit two-way coupling of the BEM-FEM solvers. The Boundary Element Method (BEM) solver of ComPropApp gives it an edge over Reynolds Averaged Navier Stokes Equations (RANSE) solvers in terms of computation time and cost. Hence, it is suitable for the initial design stage. The propeller used in this study is developed under the French Research Project; FabHeli. The validation is done by performing different types of FSI analysis through commercial RANSE solver (STAR-CCM+) and FEM solver (FEMAP) for only one inflow velocity of the open water case which is 10.3 m/s. The fluid solver of ComPropApp (PROCAL) is a Boundary Element Method (BEM) solver that is based on the potential flow theory while the structural solver (TRIDENT) is a FEM solver. The study is divided into four different cases; BEM-FEM one-way coupled FSI analysis, RANSE-FEM one-way coupled FSI analysis, BEM-FEM explicit two-way coupled FSI analysis with ComPropApp and RANSE-FEM implicit two-way coupled FSI analysis with STAR-CCM+. The calculated values of stresses, displacement, and forces from all the methods are compared and the conclusion is drawn.

scholarly journals Modification of boundary condition for the optimization of natural frequencies of plate structures with fluid loading

2018 ◽  
Vol 10 (8) ◽  
pp. 168781401879600 ◽  
Author(s):  
Dayi Ou ◽  
Cheuk Ming Mak
Keyword(s):  
Genetic Algorithm ◽  
Finite Element Method ◽  
Finite Element ◽  
Boundary Element Method ◽  
Boundary Conditions ◽  
Boundary Element ◽  
Natural Frequencies ◽  
Fluid Loading ◽  
Loaded Plate ◽  
Element Method

A finite element method, boundary element method, and genetic algorithm combined method is developed for the optimization of natural frequencies of fluid-loaded plates. In this method, the coupled finite element method–boundary element method is used for the free flexural vibration analysis of plates with arbitrary fluid loading effects and arbitrary elastic boundary conditions, and the genetic algorithm method is combined with the finite element method–boundary element method for searching the optimal values of plate’s boundary parameters. By using this method, multiple natural frequencies of a given fluid-loaded plate can be optimized simultaneously to different target values. The coupled finite element method–boundary element method is first validated by comparing with earlier published results. The proposed optimization method is then applied to the optimal boundary condition design of four different cases. The results show natural frequencies of a fluid-loaded plate are sensitive to its boundary conditions. The possibility of optimizing the natural frequencies of a fluid-loaded plate by modifying boundary conditions is demonstrated, as well as the effectiveness of the proposed method as a structural optimization tool. According to the authors’ knowledge, this study is the first attempt of optimizing fluid-loaded plate natural frequencies by considering arbitrary boundary conditions as optimization variables.

scholarly journals Multi-step Inverse Analysis for Rebar Corrosion using Genetic Algorithm and Boundary Element Method

2008 ◽  
Vol 57 (6) ◽  
pp. 282-287 ◽  
Author(s):  
Koichi Minagawa ◽  
Keisuke Hayabusa ◽  
Kazuhiro Suga ◽  
M. Ridha ◽  
Kenji Amaya ◽  
...  
Keyword(s):  
Genetic Algorithm ◽  
Boundary Element Method ◽  
Boundary Element ◽  
Inverse Analysis ◽  
Rebar Corrosion ◽  
Element Method
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