• Wind and Structures
• /
• 제31권2호
• /
• pp.85-102
• /
• 2020

Accurate load evaluation is essential in any performance-based design. Design wind speeds and associated wind loads are well defined for synoptic boundary layer winds but not for thunderstorms. The method presented in the current study represents a new approach to obtain design wind speeds associated with thunderstorms and their gust fronts using historical data and Monte Carlo simulations. The method consists of the following steps (i) developing a numerical model for thunderstorm downdrafts (i.e. downbursts) to account for storm translation and outflow dissipation, (ii) utilizing the model to characterize previous events and (iii) extrapolating the limited wind speed data to cover life-span of structures. The numerical model relies on a previously generated CFD wind field, which is validated using six documented thunderstorm events. The model suggests that 10 parameters are required to describe the characteristics of an event. The model is then utilized to analyze wind records obtained at Lubbock Preston Smith International Airport (KLBB) meteorological station to identify the thunderstorm parameters for this location, obtain their probability distributions, and utilized in the Monte Carlo simulation of thunderstorm gust front events for many thousands of years for the purpose of estimating design wind speeds. The analysis suggests a potential underestimation of design wind speeds when neglecting thunderstorm gust fronts, which is common practice in analyzing historical wind records. When compared to the design wind speed for a 700-year MRI in ASCE 7-10 and ASCE 7-16, the estimated wind speeds from the simulation were 10% and 11.5% higher, respectively.

• 한국환경과학회지
• /
• 제18권8호
• /
• pp.825-831
• /
• 2009

A first step review is completed on the suitability of European designed wind turbines in an East Asia climate. Six parameters are chosen for detailed analysis of proper meteorological measures from flat, hilly, forested, coastal and offshore sites in West Europe and East Asia: mean wind speed, 10 minute mean wind speed distribution, turbulence intensity, wind shear, 3 second extreme wind speed and 10 minute direction change. All six parameters are assessed with a view for contrast with the wind turbine design standard IEC61400. The diurnal and seasonal variation, average and extreme values of each parameter are calculated where appropriate. Industry standard software and analysis techniques have been employed to assess the applicability of existing wind turbine design standards and design guidelines for the East Asian market.

• 한국정밀공학회지
• /
• 제23권12호
• /
• pp.103-110
• /
• 2006

The rail clamp is very important device to prevent that a container crane slips along a rail due to the wind blast as well as to locate the crane in the set position during an operating mode. Recently, the design wind speed criteria were intensified from the wind speed of 16m/s to 35m/s during an operating mode, and from 50m/s to 75m/s during a stowed mode in Korea, according to the 'Inspection Criteria for Facilities and Equipments in Port' reformed after typhoon 'Maemi'. In order to design the wedge type rail clamp for the reinforced design wind speed criteria of 35m/s, we carried out the finite element analysis of the rail clamp with respect to the wedge angle, and analyzed the relationship between the wedge angle and the sliding distance of the rail clamp.

• 한국지리정보학회지
• /
• 제16권3호
• /
• pp.126-135
• /
• 2013

국토의 70%이상이 산지로 구성되어 있는 한국은 도시내부에 크고 작은 산, 언덕이 위치하고 있다. 따라서 건축구조기준에서는 건물의 풍하중 설계 시 지형의 영향에 따른 풍속의 증가를 고려하도록 하고 있지만 지형에 의한 풍속할증계수 산정 시 건물 주변에 두 개 이상의 산지가 위치하거나 지표면의 정의와 높이가 명확하지 않을 경우 설계자의 주관에 의해 지형에 의한 풍속할증계수를 산정함으로써 비합리적인 내풍설계가 이루어지고 있다. 따라서 본 논문에서는 이러한 문제점을 해결하고 보다 합리적인 지형에 의한 풍속할증계수를 산정하기 위하여 ArcGIS를 이용하여 지형에 의한 풍속할증계수를 산정하는 방법을 제시하고자 한다. 이를 위해 본 논문에서는 비교적 높은 위치정확도를 가진 1:5,000 수치지형도를 이용하여 지형에 의한 풍속할증계수 산정 시 적용범위를 명확하게 정의함으로서 지표면과 정점을 명료하게 산정하여 보다 합리적으로 지형에 의한 풍속할 증계수를 산정하였다.

• Wind and Structures
• /
• 제12권6호
• /
• pp.553-574
• /
• 2009

This paper presents statistical analysis results of wind speed and atmospheric turbulence data measured from more than 30 anemometers installed at 15 different height levels on 325 m high Beijing Meteorological Tower and is primarily intended to provide useful information on boundary layer wind characteristics for wind-resistant design of tall buildings and high-rise structures. Profiles of mean wind speed are presented based on the field measurements and are compared with empirical models' predictions. Relevant parameters of atmospheric boundary layer at urban terrain are determined from the measured wind speed profiles. Furthermore, wind velocity data in longitudinal, lateral and vertical directions, which were recorded from an ultrasonic anemometer during windstorms, are analyzed and discussed. Atmospheric turbulence information such as turbulence intensity, gust factor, turbulence integral length scale and power spectral densities of the three-dimensional fluctuating wind velocity are presented and used to evaluate the adequacy of existing theoretical and empirical models. The objective of this study is to investigate the profiles of mean wind speed and atmospheric turbulence characteristics over a typical urban area.

• Journal of Power Electronics
• /
• 제15권5호
• /
• pp.1358-1366
• /
• 2015

This study focuses on an advanced second-order sliding mode control strategy for a variable speed wind turbine based on a permanent magnet synchronous generator to maximize wind power extraction while simultaneously reducing the mechanical stress effect. The control design based on a modified version of the super-twisting algorithm with variable gains can be applied to the cascaded system scheme comprising the current control loop and speed control loop. The proposed control inheriting the well-known robustness of the sliding technique successfully deals with the problems of essential nonlinearity of wind turbine systems, the effects of disturbance regarding variation on the parameters, and the random nature of wind speed. In addition, the advantages of the adaptive gains and the smoothness of the control action strongly reduce the chatter signals of wind turbine systems. Finally, with comparison with the traditional super-twisting algorithm, the performance of the system is verified through simulation results under wind speed turbulence and parameter variations.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
• /
• pp.153-156
• /
• 2001

Maximum Power Point Tracking(MPPT) is used in wind power generation systems to maximize wind power turbin output power, irrespective of wind speed conditions and of the load electrical characteristics. In this paper we do the equivalent modeling the mechanical energy of wind power turbine according to wind speed into the synchronous generator. We analyse the equivalent modeling output part of rectifier into DC/DC converter input part theoretically. We design a control algorithm for variable voltage according to wind speed intensity and density so that load voltage of chopper is controlled steadily using the maximum power point tracking (MPPT) control method. We analyse a battery charging characteristics and a charging circuit for power storage enabling the supply of stable power to the load. We design a system and do the modeling of it analytically so that it supplies a stable power to the load by constructing a DC-AC inverter point. Also we design a charging circuit usable in actual wind power generation system of 30kW and confirm its validity.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2001년도 추계학술대회 논문집
• /
• pp.153-156
• /
• 2001

Maximum Power Point Tracking(MPPT) Is used in wind power generation systems to maximize wind power turbin output power, irrespective of wind speed conditions and of the load electrical characteristics. In this paper we do the equivalent modeling the mechanical energy of wind power turbine according to wind speed into the synchronous generator. We analyse the equivalent modeling output part of rectifier into DC/DC converter input part theoretically. We design a control algorithm for variable voltage according to wind speed intensity and density so that load voltage of chopper is controlled steadily using the maximum power point tracking(MPPT) control method. We analyse a battery charging characteristics and a charging circuit for power storage enabling the supply of stable power to the load. We design a system and do the modeling of it analytically so that it supplies a stable power to the load by constructing a DC-AC inverter point. Also we design a charging circuit usable in actual wind power generation system of 30kW and confirm its validity.

• 물과 미래
• /
• 제21권4호
• /
• pp.389-397
• /
• 1988

남해 연안 지상측정소의 과거풍속자료와 돌풍 기록으로 부터 과거의 피해 자료를 추산(Hindcasting)하고 이로부터 얻어진 지역별 피해별 연간 최대피해의 극치 계열로 부터 확율분석을 통하여 송해 설계치를 결정하는 방법이 제안되엇다. 남해 연안에 내재하는 큰 파급은 돌풍과 춘하절 계절풍에 의해 생성되며 지역별 파향별로 상당한 차이를 보인다. 재현기간이 100년인 설계 유의파의 파고는 송해에서 4.6m~ 8.8m ,조기는 8.2sec~ 12.9sec의 범위를 보인다. 남해\ulcorner\ulcorner에서 풍속 $U_1$ >15m/s의 강풍에 대하여 일반적으로 해상풍속(Uw)은 \ulcorner\ulcorner 지상관측소 풍속($U_1$)의 0.8~0.9배 정도를 나타낸다. 남해 \ulcorner\ulcorner의 지상관측소에서 지속기간의 평균풍속($U_1$)은 2$U_{10}$)의 0.7~0.9배의 값을 가지면서 역지수 함수적으로 감소한다.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 춘계학술대회 논문집
• /
• pp.1626-1629
• /
• 2005

Recently many countries have concentrated their effort on the port automation, in order to be the Hub-port, that the Ultra Large Container Ship could come alongside the Quay, in their region. As the magnitude of the container ship increase, that of the Quay crane increases from 50ton-class to 61ton-class more and more. The wind speed criteria to design the structures used in the port was upgraded from 20m/s to 40m/s due to change of the weather condition. Our laboratory could have the ability to design the wedge type rail clamp for 50ton-class Quay crane in 30m/s wind speed. Accordingly we analyzed the load condition of the Quay crane about 40m/s wind speed upgraded from 20m/s and designed the wedge type rail clamp for 50ton and 61ton-class Quay crane.