Multi-Stage Aerodynamic Design of Multi-Body Geometries via Global and Local Optimization Methods

2008 ◽  
Author(s):  
JinWoo Yim ◽  
Byung Joon Lee ◽  
Chongam Kim ◽  
Shigeru Obayashi
Keyword(s):  
Optimization Methods ◽  
Local Optimization ◽  
Aerodynamic Design ◽  
Multi Stage ◽  
Global And Local Optimization ◽  
Multi Body ◽  
Global And Local

scholarly journals Multi-objective aerodynamic optimization of high-speed train heads based on the PDE parametric modeling

2021 ◽  
Author(s):  
Shuangbu Wang ◽  
Ruibin Wang ◽  
Yu Xia ◽  
Zhenye Sun ◽  
Lihua You ◽  
...  
Keyword(s):  
High Speed ◽  
Optimization Design ◽  
Optimization Methods ◽  
Local Optimization ◽  
Parametric Modeling ◽  
High Speed Train ◽  
Aerodynamic Optimization ◽  
Surface Patches ◽  
Global And Local Optimization ◽  
Global And Local

AbstractWith the increasing running speed, the aerodynamic issues of high-speed trains are being raised and impact the running stability and energy efficiency. The optimization design of the head shape is significantly important in improving the aerodynamic performance of high-speed trains. Existing aerodynamic optimization methods are limited by the parametric modeling methods of train heads which are unable to accurately and completely parameterize both global shapes and local details. Due to this reason, they cannot optimize both global and local shapes of train heads. In order to tackle this problem, we propose a novel multi-objective aerodynamic optimization method of high-speed train heads based on the partial differential equation (PDE) parametric modeling. With this method, the half of a train head is parameterized with 17 PDE surface patches which describe global shapes and local details and keep the surface smooth. We take the aerodynamic drag and lift as optimization objectives; divide the optimization design process into two stages: global optimization and local optimization; and develop global and local optimization methods, respectively. In the first stage, the non-dominated sorting genetic algorithm (NSGA-II) is adopted to obtain the framework of the train head with an optimized global shape. In the second stage, Latin hypercube sampling (LHS) is applied in the local shape optimization of the PDE surface patches determined by the optimized framework to improve local details. The effectiveness of our proposed method is demonstrated by better aerodynamic performance achieved from the optimization solutions in global and local optimization stages in comparison with the original high-speed train head.

scholarly journals Design and Automated Optimization of an Internal Turret Mooring System in the Frequency and Time Domain

2021 ◽  
Vol 9 (6) ◽  
pp. 581
Author(s):  
Hongrae Park ◽  
Sungjun Jung
Keyword(s):  
System Design ◽  
Time Domain ◽  
Initial Conditions ◽  
Minimum Weight ◽  
Optimization Algorithms ◽  
Local Optimization ◽  
Mooring System ◽  
Floating Offshore Wind Turbines ◽  
Global And Local Optimization ◽  
Global And Local

A cost-effective mooring system design has been emphasized for traditional offshore industry applications and in the design of floating offshore wind turbines. The industry consensus regarding mooring system design is mainly inhibited by previous project experience. The design of the mooring system also requires a significant number of design cycles. To take aim at these challenges, this paper studies the application of an optimization algorithm to the Floating Production Storage and Offloading (FPSO) mooring system design with an internal turret system at deep-water locations. The goal is to minimize mooring system costs by satisfying constraints, and an objective function is defined as the minimum weight of the mooring system. Anchor loads, a floating body offset and mooring line tensions are defined as constraints. In the process of optimization, the mooring system is analyzed in terms of the frequency domain and time domain, and global and local optimization algorithms are also deployed towards reaching the optimum solution. Three cases are studied with the same initial conditions. The global and local optimization algorithms successfully find a feasible mooring system by reducing the mooring system cost by up to 52%.

Global and local optimization for optical systems

Optik ◽  
2006 ◽  
Vol 117 (3) ◽  
pp. 111-117 ◽  
Author(s):  
Xuemin Cheng ◽  
Yongtian Wang ◽  
Qun Hao ◽  
Masaki Isshiki
Keyword(s):  
Local Optimization ◽  
Optical Systems ◽  
Global And Local Optimization ◽  
Global And Local
Sign in / Sign up

Export Citation Format

Share Document