• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.16 no.8
• /
• pp.728-740
• /
• 2004

Heat sink has extended surface area for enhanced heat transfer. The enhanced convection heat transfer has been used widely, such as cooling electronic chips in the electronics industry. Heat sink usually requires an increase in the heat transfer and a decrease in the pressure drop, and must improve the performance in the flow field of industrial plants. In this study, wing fin heat sink was studied and tests were conducted in a rectangular cross sectional channel with wing fin heat sinks. The leading and trailing ends of a wing fin have a sharp edge, simulating the airfoil feature. Empirical correlations have been developed for wing fin heat sink types. And wing fin heat sinks have better cooling performance than elliptic fin and square fin types.

• International Journal of Control, Automation, and Systems
• /
• v.2 no.4
• /
• pp.494-500
• /
• 2004

The wing rock phenomenon is a high angle of attack aerodynamic motion manifested by limit cycle roll oscillations. Experimental studies reveal that direct control and manipulation of leading edge vortices, through the use of 'blowing' techniques is effective in the suppression of wing rock. This paper presents the design of a robust controller for the experimental implementation of one such 'blowing' technique - recessed angle spanwise blowing (RASB), to achieve wing rock suppression over a range of operating conditions. The robust controller employs Takagi - Sugeno fuzzy system, which is fine-tuned by experimental simulations. Performance of the controller is assessed by real-time wind tunnel experiments with an 80 degree swept back delta wing. Robustness is demonstrated by the suppression of wing rock at a range of angles of attack and free stream velocities. Numerical simulation results are used to further substantiate the experimental findings.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.1197-1201
• /
• 2001

Flutter suppression of a wing/store model is investigated. An aircraft wing with a store is modeled as a 2-D typical section. Unsteady aerodynamics of the wing/store model are computed by using Doublet Hybrid Method(DHM) in the frequency-domain, and are approximated by Minimum-state(MS) approximation. LQG controller is used to suppress the flutter of the wing/store model and the aeroelastic characteristics of the closed-loop system are investigated. The flutter characteristics of the wing/store model are improved and the flutter speed is increased up to about 16 ％.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.7
• /
• pp.493-501
• /
• 2002

Flutter suppression of a wing/store model is investigated. An aircraft wing with a store is modeled as a 2-D typical section. Unsteady aerodynamics of the wing/store model are computed by using doublet hybrid method(DHM) in the freauency-domain, and are approximated by minimumstate(MS) approximation. LQG controller is used to suppress the flutter of the wing/store model and the aeroelastic characteristics of the closed-loop system are investigated. The flutter characteristics of the wing/store model are improved and the flutter speed is increased up to about 24 %.

• Wind and Structures
• /
• v.29 no.4
• /
• pp.271-277
• /
• 2019

This work deals with designing the aircraft wing and simulating the flow behavior on it to determine the aerodynamically efficient wing design. A NACA 4412 airfoil is used to design the base wing model. A wing with a rectangular planform and the one with curved leading edge planform was designed such that their surface areas are the same. Then, a comprehensive flow analysis is carried out at various velocities and angle of attacks using computational fluid dynamics (CFD) and the results were interpreted and compared with the experimental values. This study shows that there is a significant improvement in the aerodynamic performance of the curved leading edge wing over the wing with rectangular planform.

• Advances in aircraft and spacecraft science
• /
• v.9 no.2
• /
• pp.103-117
• /
• 2022

In this paper, a novel morphing mechanism using a deployable scissor structure was proposed for a variable camber morphing wing. The mechanism was designed through the optimization process so that the rib can form the target airfoils with different cambers. Lastly, the morphing wing was manufactured and its performance was successfully evaluated. The mechanism of the morphing wing rib was realized by a set of deployable scissor structure that can form diverse curvatures. This characteristic of the structure allows the mechanism to vary the camber that refers to the airfoil's curvature. The mechanism is not restrictive in defining the target shapes, allowing various airfoils and overall morphing wing shape to be implemented.

• 한국전산유체공학회:학술대회논문집
• /
• 2000.05a
• /
• pp.84-90
• /
• 2000

Ground effect of three-dimensional wing is studied. LU-factored Implicit upwind TVD scheme and Baldwin-Lomax turbulence model are used for this calculation. To investigate ground effect, NACA 4415 wing at M=0.5 calculated. Two different angles of attack and three cases of flight height are calculated. As increasing angle of attack, the ground effect becomes strong. In case of NACA 4415 wing in ground effect, strength of wing tip vortex becomes stronger than that of free flight.

• International Journal of Aeronautical and Space Sciences
• /
• v.15 no.4
• /
• pp.383-395
• /
• 2014

According to the requirement of wing weight estimation and frequent adjustments during aircraft conceptual design, a wing weight estimation method considering the constraints of structural strength and stiffness is proposed to help designers make wing weight estimations rapidly and accurately. This method implements weight predictions on the basis of structure weight optimization with stiffness constraints and strength constraints, which include achievement of wing shape parametric modeling, rapid structure layout, finite element (FE) model automated generation, load calculation, structure analysis, weight optimization, and weight computed based on modeling. A software tool is developed with this wing weight estimation method. This software can realize the whole process of wing weight estimation with the method and the workload of wing weight estimation is reduced because much of the work can be completed by the software. Finally, an example is given to illustrate that this weight estimation method is effective.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.1329-1332
• /
• 2007

In this study, the design method of flexible wing model for gust response measurement wind tunnel test was presented. The design concept proposed herein was validated by modal testing of the flexible wing model manufactured. In addition, aeroservoelastic modeling method for flexible wing model was presented and validated by comparing the gust response analysis results from the method proposed herein with those of commercial software. The gust response characteristics of the flexible wing model was studied by wind tunnel test for measuring the flexible wing gust response due to the induced gust excitation by gust generator. The aeroservoelastic modeling methods proposed and the wind tunnel test results obtained in this study can be applied for wind tunnel testing of the flexible wing for gust response alleviation.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.22 no.2
• /
• pp.27-33
• /
• 2014

There are several methods to improve the flight efficiency of HALE(High Altitude Long Endurance) UAV(Unmaned Aerial Vehicle). Airframe structural point of view, weight reduction of the airframe structure is the most important method to improve the flight efficiency. In order to reduce the weight of airframe structures, new concepts which are different from traditional airframe structure design such as the mylar wing skin should be introduced. The spar is the most important component in a mylar skin wing structure, so the spar weight reduction is the key point for reduction of the wing structural weight. In this study, design trade-off study for the front spar of the HALE UAV wing is conducted in order to reduce the weight. Design and analysis procedure of high aspect ratio wing spar are introduced. Several front spar structures are designed and trade-off study regarding the weight and strength for the each spar are performed. Spar design configurations are verified by the static strength test. Finally, optimal front spar design is decided and applied to the HALE UAV wing design.