스피드 스케이팅 500m 곡선주로에 대한 경기력 결정요인 분석

김건탁 ( Kim Geon-tak ),류재균 ( Ryu Jae-kyun ) 한국체육학회 2021 한국체육학회지 Vol.60 No.3

본 연구의 목적은 스피드 스케이팅 500 m 경기의 2·4코너 구간에 대한 곡선 스트로크 동작의 운동학적·운동역학적 변인과 직선과 곡선 구간별 속도 변인과의 상호관계를 연계하여 경기력에 어떠한 영향을 미치는지 관계를 규명하는 것이다. 대상자는 총 8명의 엘리트 남자 스피드 스케이팅 선수들을 선정하였으며, 분석 변인으로는 구간별 평균속력과 속도 그리고 2·4코너의 속도, 스트로크당 변위, 푸시오프 각도, 스트로크 빈도, 스트로크당 행한 일의 양, 스트로크 파워로 정하였다. 그리고 Pearson’s 상관분석 및 단순회귀분석을 진행하여 다음과 같은 결론을 얻었다. 첫째, 스트로크 파워를 생성하기 위해서는 스트로크당 행한 일의 양을 높이는 것이 효율적이지만, 속도 변화량의 감소를 최소화하기 위해서는 스트로크 빈도를 유지하는 것이 중요하다. 둘째, 2코너에서 짧은 시간에 속도를 높이기 위해서 스트로크 빈도를 증가시키는 것이 중요하며, 4코너에서는 스트로크당 행한 일의 양과 스트로크 파워를 높이고 스트로크 빈도를 유지하여야 한다. 셋째, 2코너 끝 지점의 순간속도는 스트로크 빈도(r=.857, p<.01)와 정적 상관, 스트로크당 행한 일의 양(r=-.747, p<.05)과는 부적 상관이 있다. 반면에 4코너 끝 지점의 순간속도는 스트로크당 행한 일의 양(r=.847, p<.01)과 스트로크 파워(r=.895, p<.01)와 정적 상관이 있다. 넷째, 2코너 평균속력(R²=0.820), 4코너 평균속력(R²=0.696), 400∼500 m home straight 평균속도(R²=0.645)의 순으로 속도를 높이는 것이 500 m 경기력을 향상시키는 것이다. The purpose of this study was to investigate the relationship between the kinematic and kinetic variables of the stroke for the 2nd and 4th corners in the official speed skating 500 m race and the speed variables of each straight and curve section to determine their effects on performance. A total of 8 elite speed skaters were selected as subjects in this study, the kinematic and kinetic variables were the mean speed and velocity by each section, displacement per stroke, push-off angle, stroke frequency, work per stroke, and stroke power in the 2nd & 4th corners. Pearson’s correlation analysis and simple regression analysis were conducted to investigate the relationship between kinematic and kinetic variables in each analyzed section and 500 m performance. First, To generate stroke power, it is efficient to increase the amount of work per stroke rather than the stroke frequency, but it is important to maintain the stroke frequency to minimize the loss in the speed change. Second, It is important to increase the stroke frequency for fast speed in the 2nd corner, increase the amount of work per stroke and stroke power in the 4th corner, and keep the stroke frequency to maintain the high speed. Third, The instantaneous velocity at the end of the 2nd corner is positively correlated with the stroke frequency(r=.857, p<.01), and negatively correlated with the amount of work per stroke (r=-.747, p<.05). On the other hand, the instantaneous velocity at the end of the 4th corner is positively correlated with the amount of work per stroke(r=.847, p<.01) and stroke power(r=.895, p<.01). Fourth, Increasing the mean speed in the order of mean speed of the 2nd corner(R²=0.820), mean speed of the 4th corner(R²=0.696), and mean velocity of 400∼500 m home straight(R²=0.645) improves the 500 m performance.

A new method to analyse the speed power performance of operating ships and its implementation

박범진,신명수,이경중,기민석 한국마린엔지니어링학회 2019 한국마린엔지니어링학회지 Vol.43 No.10

Ship operators need means to analyse their fleet’s performance in order to maintain their competitiveness. Important decisions such as voyage planning and scheduled maintenance, are all made based on a ship’s performance. However, there is no reliable method to estimate a ship’s performance. ISO19030 provides a means to measure the changes in performance but is only applicable to data collected over a relatively long period of time and is unsuitable for comparing the performance of sister ships. In this study, we implemented a software to analyse a ship’s performance. To meet the ship operator’s requirements, a new speed power performance analysis method based on ISO15016:2015 is proposed. The proposed method first evaluates the added or decreased resistance due to the environmental changes including wind, waves and water density first. Then, the measured shaft power is corrected by direct power method and finally corrected to reference displacement for comparison. The results of its implementation, a software called SPA, and its application to two ships, a 176K bulk carrier and an 8600TEU container carrier, are described herein.

The Effect of Uncertainty in Sea Trial Measurement System on Speed-Power Performance

Dae-Won Seo,Jackyou Noh 해양환경안전학회 2020 海洋環境安全學會誌 Vol.26 No.3

Sea trial tests are necessary to verify speed-power performance, and are an import contract between ship owners and shipyards. The International Organization for Standardization (ISO) published ISO 15016:2015, which specifies the correlation method between model and full-scale ships. The results of sea trials have been questioned because of the uncertainty of speed and power measurements, especially when sea conditions differ from ideal calm water conditions. In this paper, such uncertainties were investigated by utilizing the standard speed-power trial analysis procedure defined in ISO 15016:2015 through Monte Carlo simulations. It was found that the expanded uncertainty of the delivered power (PDid) at 95 % confidence interval (k = 2) was ±1.5 % under 75 % MCR conditions.

Comparative study of prediction methods of power increase and propulsive performances in regular head short waves of KVLCC2 using CFD

Cheol-Min Lee,Jin-Hyeok Seo,Jin-Won Yu,Jung-Eun Choi,이인원 대한조선학회 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

This paper employs computational tools to predict power increase (or speed loss) and propulsion performances in waves of KVLCC2. Two-phase unsteady Reynolds averaged Navier-Stokes equations have been solved using finite volume method; and a realizable k-ε model has been applied for the turbulent closure. The free-surface is obtained by solving a VOF equation. Sliding mesh method is applied to simulate the flow around an operating propeller. Towing and self-propulsion computations in calm water are carried out to obtain the towing force, propeller rotating speed, thrust and torque at the selfpropulsion point. Towing computations in waves are performed to obtain the added resistance. The regular short head waves of l/LPP ¼ 0.6 with 4 wave steepness of H/l ¼ 0.007, 0.017, 0.023 and 0.033 are taken into account. Four methods to predict speed-power relationship in waves are discussed; Taylor expansion, direct powering, load variation, resistance and thrust identity methods. In the load variation method, the revised ITTC-78 method based on the ‘thrust identity’ is utilized to predict propulsive performances in full scale. The propulsion performances in waves including propeller rotating speed, thrust, torque, thrust deduction and wake fraction, propeller advance coefficient, hull, propeller open water, relative rotative and propulsive efficiencies, and delivered power are investigated.

Comparative study of prediction methods of power increase and propulsive performances in regular head short waves of KVLCC2 using CFD

Lee, Cheol-Min,Seo, Jin-Hyeok,Yu, Jin-Won,Choi, Jung-Eun,Lee, Inwon The Society of Naval Architects of Korea 2019 International Journal of Naval Architecture and Oc Vol.11 No.2

This paper employs computational tools to predict power increase (or speed loss) and propulsion performances in waves of KVLCC2. Two-phase unsteady Reynolds averaged Navier-Stokes equations have been solved using finite volume method; and a realizable k-ε model has been applied for the turbulent closure. The free-surface is obtained by solving a VOF equation. Sliding mesh method is applied to simulate the flow around an operating propeller. Towing and self-propulsion computations in calm water are carried out to obtain the towing force, propeller rotating speed, thrust and torque at the self-propulsion point. Towing computations in waves are performed to obtain the added resistance. The regular short head waves of λ/LPP = 0.6 with 4 wave steepness of H/λ = 0.007, 0.017, 0.023 and 0.033 are taken into account. Four methods to predict speed-power relationship in waves are discussed; Taylor expansion, direct powering, load variation, resistance and thrust identity methods. In the load variation method, the revised ITTC-78 method based on the 'thrust identity' is utilized to predict propulsive performances in full scale. The propulsion performances in waves including propeller rotating speed, thrust, torque, thrust deduction and wake fraction, propeller advance coefficient, hull, propeller open water, relative rotative and propulsive efficiencies, and delivered power are investigated.

9.77톤급 소형어선의 3자유도 구속모형시험을 통한 선속 별 운항성능 추정

김동진,안해성,조경희,여동진 한국항해항만학회 2023 한국항해항만학회지 Vol.47 No.6

본 연구에서는 연안 및 항만 내에서 운항이 빈번한 총톤수 9.77톤급 소형어선을 대상으로 구속모형시험을 수행하고, 선속 별 운항성능을 추정하였다. 연안 및 항내에서는 소형 어선이 주로 중저속 운항함을 고려하여, 구속모형시험은 8노트 이하에서 수행하였다. 실선을 1/3.5 축소한 모형선을 대상으로 선형예인수조의 프로펠러 단독특성, 저항, 자항추진 시험을 통하여 실선 선속 별 저항추진성능을 추정하였다. 그리고 타 단독특성, 3자유도 정적 및 동적 HPMM 시험을 수행하고 수평면 운항모델 내 유체력 미계수들을 도출하였다. 특히 사항 및 순수선수동요시험은 2∼8노트 영역에서 수행되었고, 주요 선형 유체력 미계수들이 선속에 따라 현저하게 변화함을 파악하였다. 선형 유체력 미계수들을 Froude 수에 대한 함수화 한 후, 선속 별 시뮬레이션을 통하여 대상 어선의 조종성능을 검토하였다. In this study, a mathematical model of a 9.77 G/T small fishing vessel was established based on captive model tests. The powering and manoeuvring performances of the vessel in the harbor and coastal sea were focused on, so captive model tests were conducted up to the full-scale speed of 8 knots. Propeller open water, resistance, and self-propulsion tests of a 1/3.5-scaled model ship were performed in a towing tank, and the full-scale powering performance was predicted. Hydrodynamic coefficients in the mathematical model were obtained by rudder open water, horizontal planar motion mechanism tests of the same model ship. In particular, in static drift and pure yaw tests which were conducted at a speed of 2 to 8 knots, the linear hydrodynamic coefficients varied with the ship speed. The effect of the ship speed on the linear coefficients was considered in the mathematical model, and manoeuvring motions, such as turning circles and zig-zags, were simulated with various approach speeds and analyzed.

신형고속열차용 동력차 구조체 하중시험에 관한 연구

김원경(Weon-Kyong Kim) 한국철도학회 2015 한국철도학회 학술발표대회논문집 Vol.2015 No.10

본 논문은 국내 동력집중 식 신형고속열차용 동력차 구조체 하중시험에 관하여 연구한 내용이다. 철도차량용 구조체는 안전운행에 기본이 되는 핵심장치로서 완성차량에 적용하기 전에 구조체의 안전성 및 신뢰성이 충분히 검증되어야 한다. 특히 동력집중식 고속열차용 동력차 구조체의 경우 기관실내의 각종 전기장치의 중량이 무겁고 다양한 형태의 장치가 복잡하게 배치되어 있어 구조해석 결과 중량 물에 의한 구조체에 발생되는 응력이 매우 높게 발생되고 있으며 또한, 차량운행속도가 300㎞/h 이상 고속으로 운행하기 때문에 안전성 검증이 필수적이라 할 수 있다. 구조체 안전성 검증을 위한 방법으로 철도안전법의 성능시험관련 규정에 따라 구조체 정하중 시험을 실시하여 각 하중별 응력을 평가하고 안전기준의 시험조건 및 판정기준에 따라 안전성을 평가하였으며, 각 하중별 모재부 및 용접부의 응력을 확인한 결과 안전한 것으로 확인되었다. In this study, the load test of Power car body for New High speed train. Car Body for rolling stock in safety operation of the vehicle as an essential core unit before applying to the vehicle safety and reliability should be tested sufficiently. Especially, Centralized Power-type Car Body for High speed train on the weight of the various electrical devices of the engine room heavy and various types of devices, the stress generated in the complex, it is disposed structural analysis results the heavy weight structure is generated very high. In the addition, because it runs as a vehicle driving speed to 300㎞/h high speed over safety verification it can be called essential. Structural safety by implementing a method to structure static load test in the accordance with the performance test regulations of the railway safety codes for verification was evaluated for each load by stress and to evaluate the safety, depending on the test conditions and the criteria of safety standards, the base metal part and each load results confirmed the stress of the welded portion was found to safe.

The Effect of Uncertainty in Sea Trial Measurement System on Speed-Power Performance

서대원,노재규 해양환경안전학회 2020 海洋環境安全學會誌 Vol.26 No.3

Sea trial tests are necessary to verify speed-power performance, and are an import contract between ship owners and shipyards. The International Organization for Standardization (ISO) published ISO 15016:2015, which specifies the correlation method between model and full-scale ships. The results of sea trials have been questioned because of the uncertainty of speed and power measurements, especially when sea conditions differ from ideal calm water conditions. In this paper, such uncertainties were investigated by utilizing the standard speed-power trial analysis procedure defined in ISO 15016:2015 through Monte Carlo simulations. It was found that the expanded uncertainty of the delivered power (PDid) at 95% confidence interval (k=2) was ±1.5% under 75% MCR conditions.

The Effect of Uncertainty in Sea Trial Measurement System on Speed-Power Performance

Seo, Dae-Won,Noh, Jackyou The Korean Society of Marine Environment and safet 2020 海洋環境安全學會誌 Vol.26 No.3

Sea trial tests are necessary to verify speed-power performance, and are an import contract between ship owners and shipyards. The International Organization for Standardization (ISO) published ISO 15016:2015, which specifies the correlation method between model and full-scale ships. The results of sea trials have been questioned because of the uncertainty of speed and power measurements, especially when sea conditions differ from ideal calm water conditions. In this paper, such uncertainties were investigated by utilizing the standard speed-power trial analysis procedure defined in ISO 15016:2015 through Monte Carlo simulations. It was found that the expanded uncertainty of the delivered power (P_Did) at 95 % confidence interval (k = 2) was ±1.5 % under 75 % MCR conditions.

Fast Electro-Mechanical Performance Evaluation Tool for Synchronous Reluctance Machine

M. A. H. Rasid,Khadija Benkara,Vincent Lanfranchi 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.11

The absence of high-cost rare-earth magnet on the rotor of Synchronous Reluctance machine makes it one of the best option for an actuator in applications with high ambient temperature. Combined with an optimized rotor structure, it can deliver good performance. In the early design phase of the machine, development cost reduction of prototyping and testing can be obtained by having a fast electro-mechanical model that can evaluate the machine’s essential performance: operating envelope, power factor and efficiency. Therefore this study proposes a fast analytical tool that evaluates the electro-mechanical performance of a given Syncrel machine. Experimental evaluations done on a prototype machine has proven the validity and robustness of the tool. The resulting tool is ready to be used for fast electro-mechanical performance evaluation of any Syncrel machine topology with any power supply and control variations.