• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.168-169
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• 2005

The optimum design and the performance analysis software called POSEIDON for the HAWT (Horizontal Axis Wind Turbine) was developed by use of BEMT. The Prandtl's tip loss theory was adopted to consider the blade tip loss. The lift and the drag coefficient of S-809 airfoil were predicted via X-FOIL and also the post stall characteristics of S-809 were estimated by the Viterna's equations. All the predicted aerodynamic characteristics are fairly well agreed with the wind tunnel test results, performed by Sommers in Delft university of technology. The rated power of the testing rotor is 20kW(FIL-20) at design conditions. The experimental aerodynamic parameters and the X-FOIL data were used for the power prediction of the FIL-20 respectively. The comparison results shows good agreement in power prediction.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.6
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• pp.669-676
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• 2006

The optimum design and the performance analysis software called POSEIDON for the HAWT (Horizontal Axis Wind Turbine) is developed by use of BEMT, which is the standard computational technique for prediction of power curves of wind turbines. The Prandtl's tip loss theory is adopted to consider the blade tip loss. The lift and the drag coefficient of S-809 airfoil are predicted via X-FOIL and the post stall characteristics of S-809 also are estimated by the Viterna's equations.$^{[13]}$ All the predicted aerodynamic characteristics are fairly well agreed with the wind tunnel test results. performed by Sommers in Delft university of technology. The rated power of the testing rotor is 20kW(FIL-20) at design conditions. The experimental aerodynamic parameters and the X-FOIL data are used for the power Prediction of the FIL-20 respectively The comparison results shows good agreement in power prediction.

• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.28-36
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• 2006

Numerical analysis of wind turbine scale effect was performed by using commercial CFD code, Fluent. For the numerical analysis of wind turbine, the three dimensional Navier-Stokes solver with various turbulence models was tested. As a turbulence mode, the realizable k-e turbulence model was selected for the simulation of wind turbines. To validate the present method, performance of NREL (National Renewable Energy Laboratory) Phase VI wind turbine model was analyzed and compared with its wind tunnel test and blind test data. Using the present method, numerical simulations for various size of wind tunnel models were carried out and characteristics were analyzed in detail. For wind tunnel test model, the size of nacelle may not be scaled down precisely because of available motor. The effect of nacelle size was also computed and analyzed though CFD simulation. The present results showed the good correlations in pre-stall region but much to be improved in post-stall region. In 2006 and 2007, the performance and the scale effect of standard wind turbine model will be tested in KARI(Korea Aerospace Research Institute) LSWT(Low Speed Wind Tunnel) and the present results will be validated with the wind tunnel data.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.3
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• pp.359-367
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• 2003

Supplementary feeding strategies were evaluated from pre-calving throughout lactation on 24 dual-purpose Mpwapwa breed cows in their second or greater lactation, weighing 246-455 kg. The Mpwapwa breed is an established breed of 4 Bos indicus breeds and 8% of Bos taurus. The cows were penned and stall-fed individually. Eight weeks before calving to eight weeks after calving, the cows were divided into two groups and offered hay ad libitum with either 2 kg DM (L) or 4 kg DM/day (H) concentrates. Nine weeks after calving half of the cows on L-level continued with 2 kg DM/day (L-L) while the remainder received 4 kg DM concentrate daily (L-H). Half of the cows on H-group continued with 4 kg DM/day (H-H) while the remainder received 2 kg DM/day (H-L). The concentrate mixture comprised of sunflower seed cake (33%) and maize bran (67%). The cows consumed all the concentrate offered. Hay DM intake was similar (6.8 kg/day) and tended to decrease the last two weeks before calving increased again after calving. Live weight change and body condition score were similar across treatments before calving but differed after calving (p<0.05). Heavier cows with higher condition score pre-calving had a higher body weight loss and regained weight later. After treatment reallocation, live weight change and condition differed between treatments (p<0.05). Calves were allowed to suckle milk from one quarter. The amount of milk suckled and calf weight gains were not significantly different between treatments. The cows were removed from the experiment when the milk yield was below 4 kg per day. Cows on treatment H produced 6.2 kg and on treatment L 5.0 kg saleable milk/day (p<0.05) during the first 8 weeks post partum. During the period 9-18 weeks post partum the saleable daily milk on H-H, L-H, H-L and L-L were 5.2, 4.8, 4.7 and 4.3 kg, respectively (p>0.05).

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.7
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• pp.20-28
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• 2002

In this paper, the aerodynamic performance prediction of a 30kW counter-rotating (C/R) wind turbine system has been made by using the momentum theory as well as the two-dimensional quasi-steady strip theory with special care on the wake and the post-stall effects. In order to take into account the wake effects in the performance analysis, the wind tunnel test data obtained for a scaled blade are used. Both the axial and rotational inductions behind the auxiliary rotors are determined through the wake model. In addition, the optimum chord and twist distributions along the blades are obtained from the Glauert's optimum actuator disk model considering the Prandtl's tip loss effect. The performance results of the counter-rotating wind turbine system are compared with those of the conventional single rotor system and demonstrated the effectiveness of the counter-rotating wind turbine system.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.24.1-24
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• 1996

The development of future aircraft that involves the expanded flight envelop will place increased performance requirements on the design of the flight control system. Maneuvering areas are expanding into flight envelopes characterized by significantly larger levels of modeling uncertainty than encountered in present flight control designs. Conventional flight control techniques that ignore the effects of large parameter variations, modeling uncertainties and nonlinearities, will likely produce designs with poor performance and robustness. Recent advances in modern control theories called advanced control theories, most notably the H$\_$.inf./ synthesis technique, adaptive control and neural network application, offer the promise of a design technique that can produce both high performance and robust controllers for next generation aircraft. This special lecture will survey the recent development in advanced flight control and review the possible application of advanced control theories.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.728-736
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• 1996

Solid/Liquid(S/L) separation is crucial for biological treatment of animal wastewater. Liquid portion from S/L separation has less BOD-load and proper post-strip treatment can be obtained . Screen or declined sieve was normally used to separate the solid parts. For better separating efficiency a vibration and a cylindrical separator were constructed and tested. The results are summarized as follows : Solids removal efficiency and moisture content of separated solid were 15-26% and 85-88%, respectively for the vibration separator. For the cylindrical separator, solid removal efficiency and moisture content of solid were 16-39% and 86-89% , respectively. The greatest amount of drymatter was obtained when operating vibration separator with 10。 inclination and 100% vibrating power. For the cylindrical separator maximum efficiency was obtained with 40rpm and 19 inclination . The vibration and the cylindrical separator have shown 21% and 26% in BOD removal, respectively. These two types of separator were proved to be applicable methods for animal wastewater separation.

• The KSFM Journal of Fluid Machinery
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• v.11 no.5
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• pp.15-21
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• 2008

In modem wind power system of large capacity above 1MW, horizontal axis wind turbine(HAWT) is a common type. And, the optimum design of wind turbine to guarantee excellent power performance and its reliability in structure and longevity is a key technology in wind Industry. In this study, mathematical expressions based upon the conventional BEMT(blade element momentum theory) applying to basic 1MW wind turbine blade configuration design. Power coefficient and related flow parameters, such as Prandtl's tip loss coefficient, tangential and axial flow induction factors of the wind turbine analyzed systematically. X-FOIL was used to acquire lift and drag coefficients of the 2-D airfoils and we use Viterna-Corrigan formula to interpolate the aerodynamic characteristics in post-stall region. In order to predict the performance characteristics of the blade, a performance analysis carried out by BEMT method. As a results, axial and tangential flow factors, angle of attack, power coefficient investigated in this study.

• Journal of the Korean Society for Library and Information Science
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• v.38 no.4
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• pp.167-178
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• 2004

The purpose of the study is to identify the degree of relevancy on the facilities for the older persons in the public library buildings. To achieve the purpose, the study has researched and analyzed' the guidelines of the law contributing to the convenience of the handicapped, older persons, pregnant women etc(1999)' for the older persons accessing to the facilities in the public library buildings. And then, the older persons' physical standard sizes in 'Size Korea(1997)' are researched and reconfigured. The study has selected the 10 kinds in such facilities as followed : Door, Accessible Route, Stair, Elevator, Escalator, Ramp, Toilet Stall, Urinal, Table, and Post Box. As the result, the study has identified the relevancies of each facilities based on the older persons's physical standard sizes.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.827-833
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• 2008

In this study, mathematical expressions based upon the conventional BEMT(blade element momentum theory) was applied to basic 100kW wind turbine blade configuration design. Power coefficient and related flow parameters, such as Prandtl's tip loss coefficient, tangential and axial flow induction factors of the wind turbine were analyzed systematically. X-FOIL was used to acquire lift and drag coefficients of the 2-D airfoils and Viterna-Corrigan formula was used o interpolate he aerodynamic characteristics in post-stall region. Also, aerodynamic characteristics, measured in a wind tunnel to calculate he power coefficient was applied. The comparative results such as axial and tangential flow factors, power coefficients were presented in this study. Power coefficient, calculated by in-house code was compared with the GH-Bladed result. The difference of the aerodynamic characteristics caused the difference of the performance characteristics as variation as TSR.