A simulation method for macro-meteorological wind speeds with a Forward Weibull parent distribution of general index

2017 ◽  
Vol 171 ◽  
pp. 202-206 ◽  
Author(s):  
R. Ian Harris
Keyword(s):  
Simulation Method ◽  
Wind Speeds ◽  
General Index ◽  
Parent Distribution

scholarly journals Pengaruh diameter dan jumlah sudu turbin angin savonius tipe L terhadap unjuk kerja yang dihasilkan

2020 ◽  
Vol 1 (2) ◽  
pp. 61-67
Author(s):  
Mohammad Rizqi Saputra ◽  
Nur Kholis ◽  
Mohammad Munib Rosadi
Keyword(s):  
Energy Source ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Mechanical Energy ◽  
Simulation Method ◽  
Wind Speeds ◽  
Turbine Efficiency ◽  
Analysis Technique ◽  
Low Wind Speeds ◽  
Wind Source

Abstract Wind is a renewable mechanical energy source that can be used as an energy source because the energy from the wind can be used to drive wind turbines. Savonius wind turbine type L is a tool to convert wind energy into electricity with a simple construction and can work with low wind speeds. The purpose of this study was to determine the effect of differences in diameter and number of blades on the power produced. The method used is a simulation method with an artificial wind source. With a wind speed of 8 m/s. The data analysis technique used is 2-way ANOVA using the SPSS application. Variations used are 20 cm and 40 cm in diameter and the number of blades 2 and 4 . The result is a wind turbine with a variation of 40 cm and 4 blades capable of producing the best output which produces 350.98 RPM voltage of 11.64 volts current of 0.144 amperes and power of 1,676 watts. As for BHP, torque, and turbine efficiency with a variation of 40 cm and 4 blades capable of producing the best output where the generated BHP is 3.352 watts, torque 0.091 N / m efficiency 2.17. For the results of calculations with SPSS wind turbines with a diameter variation of 40 cm and 4 blades, the biggest power is 1,744 watts and for BHP produces 3.3520 watts and the efficiency reaches 2.17%. Keyword : Diameter, number of blade, Performance Abstrak Angin adalah sumber energi mekanik yang bisa diperbaharui sehingga dapat dimanfaatkan sebagai sumber energi karena dapat digunakan untuk menggerakkan turbin angin. Turbin angin savonius tipe L merupakan alat untuk mengubah energi angin menjadi listrik dengan konstruksi yang sederhana dan dapat bekerja dengan kecepatan angin yang rendah. Tujuan penelitian ini untuk mengetahui pengaruh perbedaan diameter dan jumlah sudu terhadap unjuk kerja yang dihasilkan. Metode yang digunakan adalah metode simulasi dengan sumber angin buatan. Dengan kecepatan angin 8 m/s. Teknik analisis data yang digunakan adalah ANOVA 2 arah dengan menggunakan aplikasi SPSS. Variasi yang digunakan adalah diameter 20 cm dan 40 cm serta jumlah sudu 2 dan 4. Hasilnya turbin angin dengan variasi 40 cm dan 4 sudu mampu menghasilkan output terbaik yang dimana menghasilkan RPM 350,98 tegangan 11,64 volt arus 0,144 ampere dan daya 1,676 watt. Sedangkan untuk BHP, torsi, dan efisensi turbin dengan variasi 40 cm dan 4 sudu mampu menghasilkan output yang terbaik dimana BHP yang dihasilkan adalah 3,352 watt, torsi 0,091 N/m efisisensi 2,17. Untuk hasil perhitungan dengan SPSS turbin angin dengan variasi diameter 40 cm dan 4 sudu menghasilkan daya terbesar yakni 1,744 watt dan untuk BHP menghasilkan 3,3520 watt dan efisiensinya mencapai 2,17 % untuk torsi tertinggi dicapai turbin variasi 40 cm 2 sudu dengan torsi 0,116.   Kata kunci : diameter, jumlah sudu, unjuk kerja

scholarly journals Investigation of the Superposition Effect of Oil Vapor Leakage and Diffusion from External Floating-Roof Tanks Using CFD Numerical Simulations and Wind-Tunnel Experiments

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 299
Author(s):  
Jie Fang ◽  
Weiqiu Huang ◽  
Fengyu Huang ◽  
Lipei Fu ◽  
Gao Zhang
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Simulation Method ◽  
Vapor Concentration ◽  
Monitoring And Control ◽  
Wind Tunnel Experiments ◽  
Ambient Wind ◽  
Wind Speeds ◽  
High Concentrations ◽  
And Control

Based on computational fluid dynamics (CFD) and Realizable k-ε turbulence model, we established a numerical simulation method for wind and vapor-concentration fields of various external floating-roof tanks (EFRTs) (single, two, and four) and verified its feasibility using wind-tunnel experiments. Subsequently, we analysed superposition effects of wind speed and concentration fields for different types of EFRTs. The results show that high concentrations of vapor are found near the rim gap of the floating deck and above the floating deck surface. At different ambient wind speeds, interference between tanks is different. When the ambient wind speed is greater than 2 m/s, vapor concentration in leeward area of the rear tank is greater than that between two tanks, which makes it easy to reach explosion limit. It is suggested that more monitoring should be conducted near the bottom area of the rear tank and upper area on the left of the floating deck. Superposition in a downwind direction from the EFRTs becomes more obvious with an increase in the number of EFRTs; vapor superposition occurs behind two leeward tanks after leakage from four large EFRTs. Considering safety, environmental protection, and personnel health, appropriate measures should be taken at these positions for timely monitoring, and control.

scholarly journals Analisa Aliran Angin Pada Sudu Turbin Angin Savonius Tipe-U Berbasis Software

2018 ◽  
Vol 4 (2) ◽  
pp. 93
Author(s):  
Delffika - Canra ◽  
Meri Rahmi ◽  
Emin Haris
Keyword(s):  
Renewable Energy ◽  
Aspect Ratio ◽  
Wind Energy ◽  
Wind Turbine ◽  
Electrical Energy ◽  
Simulation Method ◽  
Renewable Energy Resources ◽  
Wind Speeds ◽  
Low Wind Speeds ◽  
Turbine Construction

Generally, wind energy sources in Indonesia's coastal areas is one of the potential sources of renewable energy (renewable energy resources) which are abundant, environmentally friendly and renewable. Savonius wind turbines can produce relatively high torque even at low wind speeds. Because it is very well developed to produce electrical energy. To get a large electric power, a large turbine construction is also needed which also certainly requires a large cost. For this reason, it is necessary to develop the dimensions of this wind turbine construction which is known as aspect ratio (Ar). The Ar that has been researched is the blade section, and other values. While the arch depth or the length of the blade arc in U -type is still likely to be researched. Therefore, it is necessary to do research on the U-type blade arc to get greater power than before. In addition to the experimental method with a prototype of the U type Savonius wind turbine with a number of 2 blades, a software-based simulation method will be carried out to analyze the air flow on the wind turbine blade. Parameters varied only with the aspect ratio of the arc length and blade cross section width, other parameters follow the previous research. This analysis will be a comparative data with experimental methods. The expected simulation results obtain the best aspect ratio (Ar) blade in capturing wind energy.

scholarly journals An Improved Typhoon Simulation Method Based On Latin Hypercube Sampling Method

2021 ◽  
Author(s):  
Jianpeng Sun ◽  
Guanjun Lv ◽  
Wenfeng Huang ◽  
Rong Wang ◽  
Xiaogang Ma
Keyword(s):  
Sampling Method ◽  
Correlation Coefficients ◽  
Latin Hypercube Sampling ◽  
Simulation Method ◽  
Return Periods ◽  
Latin Hypercube ◽  
Wind Speeds ◽  
Extreme Wind ◽  
Extreme Wind Speed ◽  
Extreme Wind Speeds

Abstract In order to further improve the prediction accuracy of typhoon simulation method for extreme wind speed in typhoon prone areas, an improved typhoon simulation method is proposed by introducing the Latin hypercube sampling method into the traditional typhoon simulation method. In this paper, the improved typhoon simulation method is first given a detailed introduction. Then, this method is applied to the prediction of extreme wind speeds under various return periods in Hong Kong. To validate this method, two aspects of analysis is carried out, including correlation analysis among typhoon key parameters and prediction of extreme wind speeds under various return periods. The results show that the correlation coefficients among typhoon key parameters can be maintained satisfactorily with this improved typhoon simulation method. Compared with the traditional typhoon simulation method, extreme wind speeds under various return periods obtained with this improved typhoon simulation method are much closer to the results obtained with historical typhoon wind data.

scholarly journals Research on Simulation Method of Missile Adapter’s Separation Based on Combined Calculation

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Miao Chen ◽  
Yi Jiang ◽  
Shaoyan Shi ◽  
Wei Zeng
Keyword(s):  
Grid Method ◽  
Simulation Method ◽  
Separation Process ◽  
Force Analysis ◽  
Wind Speeds ◽  
Force And Motion ◽  
Aerodynamic Parameters ◽  
Simulation Results ◽  
Container Type ◽  
Good Agreement

In the background of a container-type vertical launch missile, the simulation method of adapter separation in different wind speeds is researched. Based on force analysis of the adapters during their separation from the missile, the dynamic and kinematics equations of the adapter separation are established. The adapter’s aerodynamic parameters at different attitudes getting from the numerical wind tunnel are chosen to be the input. Through the dynamic simulation of the separation process of the adapters, the simulation results are in good agreement with the experimental data. The trajectory and placement distribution of adapters are obtained during the analysis of force and motion stance at different wind speeds. Then the relative distances between the adapter and missile or launch facility are determined. At the same time, it can be estimated that the combined calculation will save about two-thirds of time compared with dynamic grid method computing, which provides a significant guidance for the simulation method of adapter separation.

scholarly journals Non-contact Dynamic Capacity-Increasing of Overhead Conductor Based on Cooling Tester (CT)

2020 ◽  
Vol 185 ◽  
pp. 01078
Author(s):  
Rui Wang ◽  
Ruidong Peng ◽  
Xiangyang Peng ◽  
Zhao Liu ◽  
Jiajian Huang ◽  
...  
Keyword(s):  
Simulation Method ◽  
Cooling Capacity ◽  
Testing Device ◽  
Obvious Effect ◽  
Dynamic Capacity ◽  
Ambient Temperatures ◽  
Wind Speeds ◽  
Element Simulation ◽  
Thermal Balance Equation ◽  
Installation Cost

The traditional dynamic capacity-increasing technology of overhead conductors needs to monitor the operation state of conductors (temperature, sag, etc.), and the relevant sensors are usually installed directly on the surface of conductors. The installation cost is high, and the operating maintenance is complicated. In this paper, a non-contact dynamic capacity-increasing method for overhead conductors based on CT is proposed. Firstly, the theory of the non-contact dynamic capacity-increasing method for conductors is introduced, and a cooling testing device is designed according to the theory. Then, the cooling index is defined to represent the cooling capacity of the object, and the corresponding cooling indexes for the conductors and the CT are calculated based on the steady-state thermal balance equation. By establishing a cooling correlation model for the conductors and the CT, the calculation for the dynamic ampacity of the conductors can be obtained. Finally, the cooling conditions of cooling testing device at different ambient temperatures and wind speeds are calculated through the finite element simulation method. Combined with the dynamic capacityincreasing method proposed in this paper, the corresponding ampacity value are obtained, and the effect of capacity increase is analyzed. The results show that the non-contact dynamic capacity-increasing method based on the CT has obvious effect in capacity-increasing compared with the static ampacity.

New Insights Into the Flooding Sequence of the Costa Concordia Accident

2014 ◽  
Author(s):  
Hendrik Dankowski ◽  
Philipp Russell ◽  
Stefan Krüger
Keyword(s):  
Time Domain ◽  
Large Scale ◽  
Simulation Method ◽  
Integration Scheme ◽  
Time Step ◽  
Wind Speeds ◽  
Short Period ◽  
Water Volumes ◽  
Accident Scenarios ◽  
The Time Domain

The tragic accident of the Costa Concordia in January 2012 was one of the most severe large passenger ship accident in Europe in recent times followed by a tremendous public interest. We present the results of an in-depth technical investigation of the flooding sequence which lead to the heeling and grounding of the ship. A fast and explicit numerical flooding simulation method has been developed in the last years to better understand accidents like this one caused by complex and large scale flooding events. The flooding simulation is validated with the help of results from model tests and has been successfully applied to the investigation of several other severe ship accidents. It is based on a quasi-static approach in the time domain which evaluates the hydrostatic equilibrium at each time step. The water fluxes through the openings are computed by a hydraulic model based on the Bernoulli equation. Large and partly flooded openings are taken into account as well as conditional openings like the opening, closing and breaking of doors. The fluxes are integrated in the time domain by a predictor-corrector integration scheme to obtain the water volumes in each compartment involved in the flooding sequence. Due to the fact that the accident happened in calm water at moderate wind speeds close to the shore of the island Giglio this quasi-static numerical flooding simulation can be applied. The results of the technical investigation of the Costa Concordia accident obtained with the help of the developed method are presented. These results match well with the heel and trim motions observed during the accident and the chain of events which lead to the final position of the vessel on the rocks in front of the island Giglio. The explicit and direct approach of the method leads to a fast computational run-time of the numerical method. This allows to study several possible accident scenarios within a short period to investigate for example the influence of the opening and closing of watertight doors and to identify a most likely flooding scenario which lead to this tragic accident.

Children’s Recall of Approximations to English

1973 ◽  
Vol 16 (2) ◽  
pp. 201-212 ◽  
Author(s):  
Elizabeth Carrow ◽  
Michael Mauldin
Keyword(s):  
Language Development ◽  
Fourth Order ◽  
Third Order ◽  
Memory Processes ◽  
The Third ◽  
General Index ◽  
General Linguistic

As a general index of language development, the recall of first through fourth order approximations to English was examined in four, five, six, and seven year olds and adults. Data suggested that recall improved with age, and increases in approximation to English were accompanied by increases in recall for six and seven year olds and adults. Recall improved for four and five year olds through the third order but declined at the fourth. The latter finding was attributed to deficits in semantic structures and memory processes in four and five year olds. The former finding was interpreted as an index of the development of general linguistic processes.

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