scholarly journals Research on Wind Field Characteristics Measured by Lidar in a U-Shaped Valley at a Bridge Site

2021 ◽  
Vol 11 (20) ◽  
pp. 9645
Author(s):  
Jun Wang ◽  
Jiawu Li ◽  
Feng Wang ◽  
Guang Hong ◽  
Song Xing
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Temporal Distribution ◽  
Original Data ◽  
Bridge Site ◽  
Wind Fields ◽  
Wind Speed Profile ◽  
Measured Position ◽  
Spatio Temporal ◽  
High Consistency

Currently, research on wind fields of U-shaped valleys is rarely reported, and anemometers or wind observation towers are usually used for field measurement, but the measured position is limited and the cost is high. In order to study the wind characteristics in a mountainous U-shaped valley, a long-range, all-weather, high-precision Wind3D 6000 lidar was placed at a bridge site located in a U-shaped valley. Then, according to the data effective ratio and wind speed, nearly 6 months of original data ranging from 0 m to 810 m were analyzed statistically. It was found that the spatio-temporal distribution of wind speed and direction is obviously not uniform, and the wind parameters are correlated among different virtual wind towers (VWTs). By classification, the effective data of midspan position is taken as the research object, and the wind speed profile is divided into three categories. Type-1 shows disorderly characteristics; Type-2 shows a linear relationship; and Type-3 shows a nonlinear relationship. The wind direction is consistent with the main wind direction at the bridge site and the average wind direction of different VWTs has a high consistency. The concept of wind-direction deflection rate is put forward to describe the variation of wind direction with height. These measured wind parameters could be used as a reference for bridge wind-resistant design.

Wind tunnel tests on the characteristics of wind fields over a simplified gorge

2016 ◽  
Vol 20 (10) ◽  
pp. 1599-1611 ◽  
Author(s):  
Peng Hu ◽  
Yongle Li ◽  
Yan Han ◽  
CS Cai ◽  
Guoji Xu
Keyword(s):  
Wind Speed ◽  
Wind Tunnel ◽  
Wind Direction ◽  
Wind Field ◽  
Small Range ◽  
Wind Fields ◽  
Wind Speeds ◽  
Mean Wind Speed ◽  
Wind Characteristics ◽  
The Mean

Characteristics of wind fields over the gorge or valley terrains are becoming more and more important to the structural wind engineering. However, the studies on this topic are very limited. To obtain the fundamental characteristics information about the wind fields over a typical gorge terrain, a V-shaped simplified gorge, which was abstracted from some real deep-cutting gorges where long-span bridges usually straddle, was introduced in the present wind tunnel studies. Then, the wind characteristics including the mean wind speed, turbulence intensity, integral length scale, and the wind power spectrum over the simplified gorge were studied in a simulated atmospheric boundary layer. Furthermore, the effects of the oncoming wind field type and oncoming wind direction on these wind characteristics were also investigated. The results show that compared with the oncoming wind, the wind speeds at the gorge center become larger, but the turbulence intensities and the longitudinal integral length scales become smaller. Generally, the wind fields over the gorge terrain can be approximately divided into two layers, that is, the gorge inner layer and the gorge outer layer. The different oncoming wind field types have remarkable effects on the mean wind speed ratios near the ground. When the angle between the oncoming wind and the axis of the gorge is in a certain small range, such as smaller than 10°, the wind fields are very close to those associated with the wind direction of 0°. However, when the angle is in a larger range, such as larger than 20°, the wind fields in the gorge will significantly change. The research conclusions can provide some references for civil engineering practices regarding the characteristics of wind fields over the real gorge terrains.

scholarly journals A PROBABILISTIC MODEL FOR THE DETERMINATION OF HYDRAULIC BOUNDARY CONDITIONS IN A DYNAMIC COASTAL SYSTEM

2011 ◽  
Vol 1 (32) ◽  
pp. 38 ◽  
Author(s):  
Jacco Groeneweg ◽  
Joost Beckers ◽  
Caroline Gautier
Keyword(s):  
Wind Speed ◽  
Boundary Conditions ◽  
Water Level ◽  
Wind Direction ◽  
Wadden Sea ◽  
Water Levels ◽  
Tidal Basin ◽  
Wind Fields ◽  
Coastal System ◽  
Advanced Method

In 2011 new Hydraulic Boundary Conditions must be established for the statutory assessment of flood protection in the Wadden Sea area, which is a complex tidal system in the northern part of the Netherlands. The aim is to base these normative wave conditions on the wave simulation model SWAN and the probabilistic method Hydra-K, to be consistent with other systems as the Holland Coast and the Zeeland Delta. Assumptions made for the latter water systems, like steady state wind forcing, uniform water levels and neglect of currents, are not valid in the tidal basin of the Wadden Sea. A schematic temporal variation of both wind direction and wind speed is applied to define wind fields that drive the hydrodynamic computations. Both wind fields and resulting water level and current fields form the input of SWAN computations for a large number of combinations of basic wind speed and wind direction, offshore surge level and phase difference between tide and maximum wind speed. The result is a large database of SWAN results that is used as a look-up table in Hydra-K to transform the offshore statistics to the load on the primary sea defenses. In general the more advanced method leads to wave heights that are up to 10% lower and wave periods that are 10-20% smaller than those obtained with the method that is presently applied for the Holland Coast and the Zeeland Delta. These differences can be ascribed to the inclusion of currents and positive shoreward tilt in water level. The inclusion of relevant physics in the hydrodynamic computations increases the accuracy of the resulting HBC. Therefore, the more advanced method will be applied to determine the HBC for 2011.

High Resolution Wind Fields Retrieved From Spaceborne Synthetic Aperture Radar Images in Comparison to Numerical Models

2002 ◽  
Author(s):  
Jochen Horstmann ◽  
Wolfgang Koch ◽  
Susanne Lehner
Keyword(s):  
High Resolution ◽  
Wind Speed ◽  
Synthetic Aperture Radar ◽  
Wind Direction ◽  
Numerical Models ◽  
Synthetic Aperture ◽  
Wind Fields ◽  
Coastal Regions ◽  
Radar Images ◽  
Aperture Radar

This paper introduces a recently developed algorithm to retrieve high-resolution wind fields over the ocean surface from spaceborne synthetic aperture radar (SAR) data. The algorithm consists of two parts, the first for determining wind direction and the second for wind speed retrieval. Wind directions are extracted from wind induced streaks e.g. from boundary layer rolls, Langmuir cells, or wind shadowing, which are approximately in line with the mean wind direction. Wind speed is derived from the normalized radar cross section (NRCS) and image geometry of the SAR image, together with the local retrieved wind direction. The application of SAR-wind retrieval in coastal regions is demonstrated using data acquired aboard the European satellites ERS-1 and ERS-2 and the Canadian satellite RADARSAT-1. These data allow to measure wind fields of an area of up to 500 km × 500 km with a resolution of up to 200 m. To improve and validate the set-up of numerical high-resolution models in coastal regions SAR-retrieved wind fields offer an unique opportunity. This is shown by comparisons of wind fields measured by SAR to results of the numerical model REMO, HIRLAM and GESIMA.

scholarly journals X-band COSMO-SkyMed wind field retrieval, with application to coastal circulation modeling

Ocean Science ◽  
2013 ◽  
Vol 9 (1) ◽  
pp. 121-132 ◽  
Author(s):  
A. Montuori ◽  
P. de Ruggiero ◽  
M. Migliaccio ◽  
S. Pierini ◽  
G. Spezie
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Surface Wind ◽  
Circulation Model ◽  
Coastal Circulation ◽  
Wind Fields ◽  
Sea Surface Wind ◽  
X Band ◽  
Sar Data ◽  
Ecmwf Model

Abstract. In this paper, X-band COSMO-SkyMed© synthetic aperture radar (SAR) wind field retrieval is investigated, and the obtained data are used to force a coastal ocean circulation model. The SAR data set consists of 60 X-band Level 1B Multi-Look Ground Detected ScanSAR Huge Region COSMO-SkyMed© SAR data, gathered in the southern Tyrrhenian Sea during the summer and winter seasons of 2010. The SAR-based wind vector field estimation is accomplished by resolving both the SAR-based wind speed and wind direction retrieval problems independently. The sea surface wind speed is retrieved by means of a SAR wind speed algorithm based on the azimuth cut-off procedure, while the sea surface wind direction is provided by means of a SAR wind direction algorithm based on the discrete wavelet transform multi-resolution analysis. The obtained wind fields are compared with ground truth data provided by both ASCAT scatterometer and ECMWF model wind fields. SAR-derived wind vector fields and ECMWF model wind data are used to construct a blended wind product regularly sampled in both space and time, which is then used to force a coastal circulation model of a southern Tyrrhenian coastal area to simulate wind-driven circulation processes. The modeling results show that X-band COSMO-SkyMed© SAR data can be valuable in providing effective wind fields for coastal circulation modeling.

scholarly journals X-band COSMO-SkyMed wind field retrieval, with application to coastal circulation modeling

2012 ◽  
Vol 9 (5) ◽  
pp. 3251-3279 ◽  
Author(s):  
A. Montuori ◽  
P. de Ruggiero ◽  
M. Migliaccio ◽  
S. Pierini ◽  
G. Spezie
Keyword(s):  
Wind Speed ◽  
Wind Direction ◽  
Surface Wind ◽  
Coastal Circulation ◽  
Wind Fields ◽  
Sea Surface Wind ◽  
X Band ◽  
Circulation Modeling ◽  
Sar Data ◽  
Ecmwf Model

Abstract. In this paper, X-band COSMO-SkyMed© SAR wind field retrieval is investigated to force coastal circulation modeling. The SAR data set consists of 60 X-band Level 1B Multi-Look Ground Detected ScanSAR Huge Region COSMO-SkyMed© SAR data, gathered in the Southern Tyrrhenian Sea during the Summer and Winter seasons of 2010. The SAR-based wind vector field estimation is accomplished by resolving both the SAR-based wind speed and wind direction retrieval problems independently. The sea surface wind speed is retrieved by means of a SAR wind speed algorithm based on the Azimuth cut-off procedure, while the sea surface wind direction is provided by means of a SAR wind direction algorithm based on the Discrete Wavelet Transform Multi-Resolution Analysis. The obtained wind fields are compared with ground truth data provided by both ASCAT scatterometer and ECMWF model wind fields. SAR-derived wind vector fields and ECMWF model wind data are used to construct a blended wind product regularly sampled in both space and time, which is then used to force a coastal circulation model of a Southern Tyrrhenian coastal area to simulate wind-driven circulation processes. The modeling results clearly show that X-band COSMO-SkyMed© SAR data can be valuable in providing effective wind fields for coastal circulation modeling.

scholarly journals Spatio-Temporal Characteristics of SO2 across Weifang from 2008 to 2020

2021 ◽  
Vol 18 (22) ◽  
pp. 12206
Author(s):  
Lining Zhu ◽  
Yu Zhang ◽  
Zheng Wu ◽  
Chengcheng Zhang
Keyword(s):  
Wind Direction ◽  
Quantitative Research ◽  
Pollution Prevention ◽  
Temporal Distribution ◽  
Research Area ◽  
Small Scale ◽  
Macro Scale ◽  
Spatio Temporal ◽  
The Impact ◽  
So2 Pollution

China has achieved good results in SO2 pollution control, but SO2 pollution still exists in some areas. Analyzing the spatio-temporal distribution of SO2 is critical for regional SO2 pollution prevention and control. Compared with existing air pollution studies that paid more attention to PM2.5, NO2 and O3, and focused on the macro scale, this study took the small-scale Weifang city as the research area, analyzed the temporal and spatial changes in SO2, discussed the migration trajectory of SO2 pollution and explored the impact of wind on SO2 pollution. The results show that the average annual concentration of SO2 in Weifang has exhibited a downward trend in the past 13 years, showing the basic characteristics of “highest in winter, lowest in summer and slightly higher in spring and autumn”, “highest on Sunday, lowest on Thursday and gradually decreasing from Monday to Thursday” and “highest at 9 a.m., lowest at 4 p.m. and gradually increasing from midnight to 9 a.m.”. SO2 concentration showed obvious spatial heterogeneity: higher in the north and lower in the south. In addition, Shouguang, Changyi and Gaomi were seriously polluted. The SO2 pollution shifted from south to northeast. The clean wind direction (southeast wind and northeast wind) of Weifang city accounted for about 41%, and the pollution wind direction (northwest wind and west wind) accounted for about 7%. Drawing from the multi-scale analysis, vegetation, precipitation, temperature, transport situation and human activity were the most relevant factors. Limited to data collection, more quantitative research is needed to gain insight into the influence mechanism in the future.

Field Investigation and Wind-Environment Numerical Simulation of Cable-Stayed Bridge Site in the West Midlands Region

2011 ◽  
Vol 255-260 ◽  
pp. 4202-4206
Author(s):  
Yue Zhang ◽  
Mi Zhou
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Field Investigation ◽  
Wind Flow ◽  
Observation Data ◽  
Bridge Site ◽  
Wind Speed Profile ◽  
Long Span Bridges ◽  
Long Span ◽  
The One

The area of mountain ridge accounts for the most part of our country land. With the development of economic construction, more and more long span bridges have been built in the mountainous region of the western in China.. Combining live observed wind with numeric simulation, the wind characteristics on the western gap of valley areas are studied. On the one hand through the self-development processing of the bridge speed data to analyze massive wind observation data, the parameters (such as wind speed profile, turbulence intensity, power spectral density) used as the main basis for calculating wind loads are achieved. On the other hand wind flow around the bridge site as well as the environment around the mountain wind flow, wind speed field and the distribution of turbulent flow, etc is obtained by using CFD technology. Based on the results that is compared with that of numerical simulation by FLUENT, the reliability and efficiency of the program is testified. It would be provided with great theoretical significance and practical engineering value passes through the foregoing study.

scholarly journals Wind Characteristics in the Taiwan Strait: A Case Study of the First Offshore Wind Farm in Taiwan

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6492
Author(s):  
Ke-Sheng Cheng ◽  
Cheng-Yu Ho ◽  
Jen-Hsin Teng
Keyword(s):  
Standard Deviation ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Direction ◽  
Wind Farm ◽  
Sea Breeze ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Wind Speed Profile ◽  
Mean Wind Speed

This study analyzed the wind speed data of the met mast in the first commercial-scale offshore wind farm of Taiwan from May 2017 to April 2018. The mean wind speed and standard deviation, wind rose, histogram, wind speed profile, and diurnal variation of wind speed with associated changes in wind direction revealed some noteworthy findings. First, the standard deviation of the corresponding mean wind speed is somewhat high. Second, the Hellmann exponent is as low as 0.05. Third, afternoons in winter and nights and early mornings in summer have the highest and lowest wind speed in a year, respectively. Regarding the histogram, the distribution probability of wind is bimodal, which can be depicted as a mixture of two gamma distributions. In addition, the corresponding change between the hourly mean wind speed and wind direction revealed that the land–sea breeze plays a significant role in wind speed distribution, wind profile, and wind energy production. The low Hellmann exponent is discussed in detail. To further clarify the effect of the land–sea breeze for facilitating future wind energy development in Taiwan, we propose some recommendations.

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