Sangook Jun

Application of Collaborative Optimization Using Response Surface Methodology to an Aircraft Wing Design

Collaborative optimization ( CO ) i s a multi -level decomposed methodology for a large scale multidisciplinary design optimization. The collaborative optimization is known to have computational and organizational advantages. Its decomposed architecture along disciplines removes a necessity o f direct communication between disciplines and guarantees the autonomy of disciplin es . However, the collaborative optimization has several problems at convergence characteristics and computation time. In this study, such features are discussed and some sug gestions are made to improve the performance of collaborative optimization. In doing so, the collaborative optimization is applied to aircraft wing design problems . Genetic algorithm is used for the system level optimization with gradient -based method as a subspace optimization algorithm , and response surfaces are replaced as analysis in subspace. It is shown that such a n application of optimization algorithms and the response surface method improves convergence characteristics. Constructing response surfac es of analysis in subspace and applying the collaborative optimization method to the aero -structural multidisciplinary optimization of the transonic wing, its results are compared with the multidisciplinary feasible method and original CO .

Application of Collaborative Optimization Using Genetic Algorithm and Response Surface Method to an Aircraft Wing Design

Collaborative optimization(CO) is a multi-level decomposed methodology for a large-scale multidisciplinary design optimization(MDO).CO is known to have computational and organizational advantages. Its decomposed architecture removes a necessity of direct communication among disciplines, guaranteeing their autonomy. However,CO has several problems at convergence characteristics and computation time. In this study, such features are discussed and some suggestions are made to improve the performance ofCO. Only for the system level optimization, genetic algorithm is used and gradient-based method is used for subspace optimizers. Moreover, response surface models are replaced as analyses in subspaces. In this manner,CO is applied to aero-structural design problems of the aircraft wing and its results are compared with the multidisciplinary feasible (MDF) method and the original CO. Through these results, it is verified that the suggested approach improves convergence characteristics and offers a proper solution.

Efficiency of Dynamic Mesh in Static Aeroelastic Analysis and Design Optimization Problem

Generally, the analysis using Computational Fluid Dynamics(CFD) is necessary for aircraft design. However, the analysis using CFD, it requires a lot of computational time and cost. But we can reduce grid reconstruction time of analyzing the various models if we use dynamic mesh. In addition, dynamic mesh can be an efficient technique in aeroelastic analysis and design optimization problem because these problems need grid reconstruction process frequently.

Fluid-Structure Interaction and Design Optimization of HAR wing for Endurance efficiency of S-HALE aircraft

In this paper, S-HALE aircraft wing sizing optimization is conducted at 20km altitude by modifying 3 variables including span length, aspect ratio and weight distribution along the spanwise direction of the wing for 24-hour continuous flight. Fluid-Structural Interaction is conducted for static stability of wing and high estimation of aerodynamic performance. 3dimensional Euler equation and MSC.Nastran are used for aerodynamic and structural analysis. Finally we check the energy flow of S-HALE during a day and confirme that the SHALE can fly 24-hour continuously.

FSI Analysis of HAR Wing at Low Speed Flight Condition

Fluid-Structure coupling analysis is required to handle a interaction between the analysis of fluid mechanics and structural analysis. (In this study, the analysis of fluid mechanics is as follows: aerodynamic analysis) Because of inconsistency of aerodynamic grid and structural mesh, each result of analysis needs to be converted to be holding a compatibility of another analysis. Therefore, the Fluid-Structure Interaction (FSI) problem makes lots of difficulties and more studies are required.

Multi-Objective Design Optimization of Loop Heat Pipe

An Multi-Objective optimum design of a loop heat pipe for a minimum mass and temperature is studied. The loop heat pipe has operating characteristics such as a hysteresis phenomena, liquid film occurrence in porous wick, and pressure drops, etc. In this paper, the multi-objective optimization of the LHP is executed using the hysteresis, DOE (Design of Experiment), and an approximation model to reduce a mass and temperature. And the porous wick optimization is introduced to decide a pore size and porosity for maximizing a heat transfer performance and minimizing a mass using capillary tube model.

Design Optimization of Transonic Wing/Fuselage System Using Proper Orthogona1 Decomposition

This paper presents a validation of the accuracy of a reduced order model(ROM) and the efficiency of the design optimization using a Proper Orthogonal Decomposition(POD) to transonic wing/fuselage system. Three dimensional Euler equations are solved to extrude snapshot data of the full order aerodynamic analysis, and then a set of POD basis vectors reproducing the behavior of flow around the wing/fuselage system is calculated from these snapshots. In this study, reduced order model constructed through this procedure is applied to several validation cases, and then it is confirmed that the ROM has the capability of the prediction of flow field in the space of interest. Additionally, after the design optimization of the wing/fuselage system with the ROM is performed, results of the ROM are compared with results of the design optimization using response surface model(RSM). From these, it can be confirmed that the design optimization with the ROM is more efficient than RSM.