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- 주제어 : Biomimetics(생체모방공학) (검색결과 20 건)
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생체모방공학을 적용한 고속철 차간 공간의 공력소음 연구
한재현(Jaehyun Han),김태민(Taemin Kim),김정수(Jungsoo Kim) 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.10
Today, high-speed trains enjoy wide acceptance as fast, convenient and environment-friendly means of transportation. However, increase in the speed of the train entails a concomitant increase in the aerodynamic noise, adversely affecting the passenger comfort. At the train speed exceeding 300 km/h, the effects of turbulent flows and vortex sheddding are greatly amplified, contributing to a significant increase in the aerodynamic noise. Drawing a biomimetic analogy from low-noise flight of owl, a method to reduce aerodynamic noise at inter-coach space of high-speed trains is investigated. The proposed method attempts to achieve the noise reduction by modifying the turbulent flow and vortex shedding characteristics at the inter-coach space. To determine the aerodynamic noise at various train speeds, wind tunnel testing and numerical CFD (Computational Fluid Dynamics) simulation for the basic inter-coach spacing model are carried out, and their results compared. The simulation and experimental results reveal that there are discrete frequency components associated with turbulent air flow at constant intervals in the frequency domain.
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생체모방공학을 이용한 고속철도 차간 공간에 적용한 부엉이 깃 형상 크기에 따른 공력소음 저감 연구
한재현(Jaehuun Han),김태민(Taemin Kim),김정수(Jungsoo Kim) 한국소음진동공학회 2012 한국소음진동공학회 학술대회논문집 Vol.2012 No.4
An analysis and design method for reducing aerodynamic noise in high-speed trains based on biomimetics of noiseless flight of owl is proposed. Wind tunnel testing and numerical CFD(Computational Fluid Dynamics) simulation for the basic inter-coach spacing model are carried out, and their results compared. To determine the effect of scaling of the owl`s flight feather on the noise reduction, a two-fold and a four-fold scaled up model of the feather are constructed, and the numerical simulations are carried out to obtain the aerodynamic noise levels for each scale. Original model is found to reduce the noise level by 10dB, while two-fold increase in length dimensions reduces the noise by 12dB. Validation of numerical solution using wind tunnel experimental measurements are presented as well
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원심 펌프의 임펠러의 생체모방공학 기반 결절 형상 최적화
오창종,이준희,박진규,강성원 한국전산유체공학회 2024 한국전산유체공학회지 Vol.29 No.3
In this study, a biomimetic tubercle shape was applied to the trailing edge of a centrifugal pump impeller in the purpose of increasing pump efficiency. Shape optimization was conducted to maximize composite pump efficiency, and the effect of flow control of the tubercle on performance improvement was analyzed. The shape optimization was carried out in two stages: sine wave shape of the tubercle was optimized, and based on the results, separate height of the tubercle was adjusted via the second optimization process. Application of the tubercle to the trailing edge increased the efficiency and reduced the turbulent kinetic energy compared to the original pump. Depending on the sinusoidal design parameters, the efficiency increased and TKE decreased as the height and number of tubercles increased. The optimization results of separate height tubercle showed that the specific tubercle has relatively larger effect on the efficiency.
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원심 펌프 임펠러의 생체모방공학 기반 최적화 연구: 입구 유동 조건의 영향
오창종,김조현,강성원 한국전산유체공학회 2024 한국전산유체공학회지 Vol.29 No.3
We aim at analyzing the mechanism of passive flow control by a biomimetic tubercle shape for impeller trailing edge(TE) in a centrifugal pump and the effect of inflow conditions. A shape optimization process of tubercle heights was performed for two different inflow conditions that approximate the conditions of a three-stage centrifugal pump. The composite efficiency of the pump increased by up to 0.77%. Compared to the streamwise periodic condition, the inflow-outflow condition showed larger increase in the pump efficiency and decrease of the turbulent intensity. Among different tubercles along TE, a specific tubercle had a relatively large effect on the results. Vortex structures were examined using the Q-criterion and swirling strength. It was observed that the orientation of the vortices behind TE changed from spanwise to streamwise by the tubercle TE. Counter-rotating streamwise vortices were generated at the top and bottom of each tubercle, and the interaction of the vortex pair led to vortex breakdown, resulting in a decrease in the turbulent intensity.
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헤라클레스 장수풍뎅이 표피의 습도-변색 효과를 응용한 생체모방형 나노 구조의 광결정 특성
김재현(JaeHyun Kim),문준혁(JunHyuk Moon),박정열(Jungyul Park),이승엽(Seung-Yop Lee) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11
The elytra from dry specimens of the Hercules beetle (Dynastes Hercules) appear khaki-green in a dry atmosphere and turn black passively under high humidity levels. The visible dry-state greenish colouration originates from a widely open porous layer located at 3μm below the cuticle surface. This layer has a three-dimensional structure, with a network of filamentary strings, arranged in layers parallel to the cuticle surface. In this study, we develop a biomimetic humidity sensor that imitates the cuticle structure of the Hercules beetle. Hydrophilic polyethylene glycol (PEG) is used as the base material for the humidity sensor. The PEG solution is infiltrated into a colloidal silica opal template and consequently photo-polymerized by UV. After polymerization, the inverse opal hydrogel (IOH) is realized by wet etching silica colloids. Not only the created IOH structure has a similar nano-porous layer, but also it shows similar spectra analysis results compared to the cuticle of the Hercules beetle, when they are exposed in wet environment.
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초소형 의공학용 유영로봇을 위한 플래핑 평판들의 추력 발생 연구
안상준(Sang-Joon An),김용대(Young-Dae Kim),맹주성(Joo-Sung Maeng),한철희(Cheol-Heui Han) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
Creatures in nature flap their wings to generate fluid dynamic forces that are required for the locomotion. Small-size creatures do not use flapping wings. Thus, it is questionable at which Reynolds number the propulsion using the flapping wings are effective. In this paper, the onset conditions of the thrust generation from the combined motion of flat plates (heaving, pitching in the motion and also tandem, biplane in the array) is investigated using a Lattice Boltzmann method. To solve the pitching motion of the plate on the regularly spaced lattices, 2-D moving boundary condition was implemented. The present method is validated by comparing the wake patterns behind a oscillating circular cylinder and its hydrodynamic characteristics with the CFD results. Present method can be applied to the design of micro flapping propulsors for biomedical use.
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이온성 고분자-금속 복합체 작동기의 소개 및 이의 응용
전진한(Jin-Han Jeon),오일권(Il-Kwon Oh) Korean Society for Precision Engineering 2011 한국정밀공학회지 Vol.28 No.11
Several biomimetic artificial muscles including the electro-active synthetic polymers (SSEBS, PSMI/PVDF, SPEEK/PVDF, SPSE, XSPSE, PVA/SPTES and SPEI), bio-polymers (Bacterial Cellulose and Cellulose Acetate) and nano-composite (SSEBS-CNF, SSEBS-C<SUB>60</SUB>, Nafion-C<SUB>60</SUB> and PHF-SPEI) actuators are introduced in this paper. Also, some applications of the developed biomimetic actuators are explained including biomimetic robots and biomedical active devices. Present results show that the developed electro-active polymer actuators with high-performance bending actuation can be promising smart materials applicable to diverse applications.
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김선기(Seongi Kim),김온아(On-Ah Kim),이승엽(Seung-Yop Lee) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11
Ionic polymer metal composite (IPMC), one of Electro-Active Polymer(EAP) actuators, has great attention due to the low-voltage driven, large deformation and its potential for artificial muscles. In this paper, we firstly review fish swimming modes using various propulsion mechanisms. Based on study on the swimming mechanisms, we develop an underwater robot actuator which mimics fanning motion of webfoot form. It consists of four actuators fabricated by using IPMC and PDMS which mimics Bio-inspired motion. Experiments using a prototype show that the webfooted IPMC actuator generates large deformation and propulsion.
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