scholarly journals Numerical Investigations of Transient Wind Shear from Passing Vehicles Near a Road Structure (Part I: Unsteady Reynolds-Averaged Navier-Stokes Simulations)

2021 ◽  
Author(s):  
Hamid Rahai ◽  
Assma Begum
Keyword(s):  
Wind Speed ◽  
Electric Power ◽  
Carbon Footprint ◽  
Wind Shear ◽  
Pressure Coefficient ◽  
Bridge Columns ◽  
Navier Stokes ◽  
Numerical Investigations ◽  
Zero Carbon ◽  
Transient Wind

In this research, the authors performed unsteady numerical simulations of a moving Ahmed body under a freeway overpass at different distances from the bridge columns in order to evaluate transient wind shear and the wind load on these columns. Results have shown that when the vehicle is at 0.75W distance from the bridge columns, an unsteady wind speed of up to 24 m/s is observed at the columns with a pressure coefficient difference of 0.9. Here W is the width of the vehicle. These results indicate with an appropriate system for harnessing these wind energy potentials, significant renewable electric power could be generated with zero carbon footprint.

Increase Power Efficientand Reliability of Electrosupply of Consumers of Low Power

GIS Business ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. 42-52
Author(s):  
Sadullayev Nasillo Nematovich ◽  
Safarov Alisher Bekmurodovich ◽  
Nematov Shuhrat Nasilloyevich ◽  
Mamedov Rasul Akif- Ogli
Keyword(s):  
Wind Speed ◽  
Probability Distribution ◽  
Low Power ◽  
Electric Power ◽  
Energy Sources ◽  
Wind Flow ◽  
Wind Rose ◽  
Energy Potential ◽  
Wind Power Installation ◽  
Wind Energy Potential

This article assesses the wind speed data and wind energy potential in the Bukhara region of Uzbekistan. In article it is stated a principle construction "hybrid" a source of the electric power consisting from wind power installation with mechanical store of energy, the solar panel with аккумулятор in common working with an electric network. The speed and direction of the wind measured at a height of 10 m were analyzed by the Weibull probability distribution functionTo determine the direction of wind flow (wind rose), a graph in Matlab environment was constructed. The method of an estimation energy of efficiency of the objects eating from several energy sources is offered. It is proved efficiency of application of such source of the electric power low power consumers

scholarly journals Experimental Study on Wake Evolution of a 1.5 MW Wind Turbine in a Complex Terrain Wind Farm Based on LiDAR Measurements

2020 ◽  
Vol 12 (6) ◽  
pp. 2467 ◽  
Author(s):  
Fei Zhao ◽  
Yihan Gao ◽  
Tengyuan Wang ◽  
Jinsha Yuan ◽  
Xiaoxia Gao
Keyword(s):  
Wind Speed ◽  
Wind Shear ◽  
Wind Farm ◽  
Wind Farms ◽  
Field Measurements ◽  
Development Trend ◽  
Asymmetric Distribution ◽  
Lidar Measurements ◽  
Wind Characteristics ◽  
The Development Trend

To study the wake development characteristics of wind farms in complex terrains, two different types of Light Detection and Ranging (LiDAR) were used to conduct the field measurements in a mountain wind farm in Hebei Province, China. Under two different incoming wake conditions, the influence of wind shear, terrain and incoming wind characteristics on the development trend of wake was analyzed. The results showed that the existence of wind shear effect causes asymmetric distribution of wind speed in the wake region. The relief of the terrain behind the turbine indicated a subsidence of the wake centerline, which had a linear relationship with the topography altitudes. The wake recovery rates were calculated, which comprehensively validated the conclusion that the wake recovery rate is determined by both the incoming wind turbulence intensity in the wake and the magnitude of the wind speed.

scholarly journals Measurement report: Effect of wind shear on PM<sub>10</sub> concentration vertical structure in urban boundary layer in a complex terrain

2021 ◽  
Author(s):  
Piotr Sekuła ◽  
Anita Bokwa ◽  
Jakub Bartyzel ◽  
Bogdan Bochenek ◽  
Łukasz Chmura ◽  
...  
Keyword(s):  
Air Pollution ◽  
Wind Speed ◽  
Case Studies ◽  
Vertical Profile ◽  
Wind Shear ◽  
Transitional Zone ◽  
Model Data ◽  
Profile Modification ◽  
Low Wind Speed ◽  
Clean Air

Abstract. The paper shows wind shear impact on PM10 vertical profiles, in Kraków, southern Poland. The data used consist of background data for two cold seasons (Sep. 2018 to Apr. 2019, and Sep. 2019 to Apr. 2020), and data for several case studies from November 2019 to March 2020. The data is composed of PM10 measurements, model data, and wind speed and direction data. The background model data come from operational forecast results of AROME model. PM10 concentration in the vertical profile was measured with a sightseeing balloon. Significant spatial variability of wind field was found. The case studies represent the conditions with much lower wind speed and a much higher PM10 levels than the seasonal average. The inversions were much more frequent than on average, too. Wind shear turned out to be the most important factor in terms of PM10 vertical profile modification. It is generated due to the relief impact, i.e. the presence of a large valley, blocked on one side with the hills. The analysis of PM10 profiles from all flights allows to distinguish three vertical zones of potential air pollution hazard within the valley (about 100 m deep) and the city of Kraków: 1. up to about 60 m a.g.l. – the zone where during periods of low wind speed, air pollution is potentially the highest and the duration of such high levels is the longest, i.e. the zone with the worst aerosanitary conditions; 2. about 60–100 m a.g.l. – transitional zone where the large decrease of PM10 levels with height is observed; 3. above 100–120 m a.g.l. – the zone where air quality is significantly better than in the zone 1, either due to the increase of the wind speed, or due to the wind direction change and advection of different, clean air masses.

scholarly journals Experimental validation of wind energy estimation

2020 ◽  
Vol 24 (6 Part A) ◽  
pp. 3795-3806
Author(s):  
Predrag Zivkovic ◽  
Mladen Tomic ◽  
Vukman Bakic
Keyword(s):  
Wind Speed ◽  
Linear Model ◽  
Linear Models ◽  
Stokes Equations ◽  
Momentum Conservation ◽  
Electricity Production ◽  
Navier Stokes ◽  
Energy Estimation ◽  
Navier Stokes Equations ◽  
Non Linear

Wind power assessment in complex terrain is a very demanding task. Modeling wind conditions with standard linear models does not sufficiently reproduce wind conditions in complex terrains, especially on leeward sides of terrain slopes, primarily due to the vorticity. A more complex non-linear model, based on Reynolds averaged Navier-Stokes equations has been used. Turbulence was modeled by modified two-equations k-? model for neutral atmospheric boundary-layer conditions, written in general curvelinear non-orthogonal co-ordinate system. The full set of mass and momentum conservation equations as well as turbulence model equations are numerically solved, using the as CFD technique. A comparison of the application of linear model and non-linear model is presented. Considerable discrepancies of estimated wind speed have been obtained using linear and non-linear models. Statistics of annual electricity production vary up to 30% of the model site. Even anemometer measurements directly at a wind turbine?s site do not necessarily deliver the results needed for prediction calculations, as extrapolations of wind speed to hub height is tricky. The results of the simulation are compared by means of the turbine type, quality and quantity of the wind data and capacity factor. Finally, the comparison of the estimated results with the measured data at 10, 30, and 50 m is shown.

scholarly journals Wind: generating power and cooling the power lines

2020 ◽  
Vol 17 ◽  
pp. 105-108
Author(s):  
Marko Kaasik ◽  
Sander Mirme
Keyword(s):  
Wind Speed ◽  
Electric Power ◽  
High Voltage ◽  
Transmission Lines ◽  
Power Transmission ◽  
Mixed Forest ◽  
Wind Farms ◽  
Power Line ◽  
Power Lines ◽  
Local Wind

Abstract. The electric power that can be transmitted via high-voltage transmission lines is limited by the Joule heating of the conductors. In the case of coastal wind farms, the wind that produces power simultaneously contributes to the cooling of high-voltage overhead conductors. Ideally this would allow for increased power transmission or decreased dimensions and cost of the conductor wires. In this study we investigate how well the wind speed in coastal wind farms is correlated with wind along a 75 km long 330 kW power line towards inland. It is found that correlations between wind speed in coastal wind farms at turbine height and conductor-level (10 m) are remarkably lower (R=0.39–0.64) than between wind farms at distances up to 100 km from each other (R=0.76–0.97). Dense mixed forest surrounding the power line reduces both local wind speed and the correlations with coastal higher-level wind, thus making the cooling effect less reliable.

Numerical and Experimental Investigations of Ship Maneuvers in Waves

2016 ◽  
Author(s):  
Ould el Moctar ◽  
Florian Sprenger ◽  
Thomas E. Schellin ◽  
Apostolos Papanikolaou
Keyword(s):  
Second Order ◽  
Navier Stokes ◽  
Experimental Investigations ◽  
Added Resistance ◽  
Numerical Investigations ◽  
Ship Maneuvers ◽  
Funded Project ◽  
Strong Winds ◽  
Energy Efficiency Design Index ◽  
Fundamental Requirement

Assuring a ship’s maneuverability under diverse conditions is a fundamental requirement for safe and economic ship operations. Considering the introduction of the Energy Efficiency Design Index (EEDI) for new ships and the related decreasing installed power on ships, the necessity arose to more accurately predict the maneuverability of ships in severe seas, strong winds, and confined waters. To address these issues, extensive experimental and numerical investigations were performed within the European funded Project SHOPERA. Here, second order forces and moments for a containership and a tanker were measured in model tests and computed by solving the Reynolds-Averaged Navier-Stokes (RANS) equations. Generally, these measured and computed second order loads (drift forces and yaw moments, added resistance) compared favorably. Furthermore, the effects of waves on zig-zag and turning circle maneuvers were investigated.

Partially Cavitating Hydrofoils: Experimental and Numerical Analysis*

2000 ◽  
Vol 44 (01) ◽  
pp. 40-58
Author(s):  
Christian Pellone ◽  
Thierry Maître ◽  
Laurence Briançon-Marjollet
Keyword(s):  
Numerical Models ◽  
Lift Coefficient ◽  
Pressure Coefficient ◽  
Navier Stokes ◽  
Viscous Effects ◽  
Local Pressure ◽  
Two Phase ◽  
Complete Study ◽  
Flow Configurations ◽  
Potential Methods

The numerical modeling of partially cavitating foils under a confined flow configuration is described. A complete study of previous numerical models highlights that the presence of a turbulent and two-phase wake, at the rear of the cavity, has a nonnegligible effect on the local pressure coefficient, the cavitation number, the cavity length and the lift coefficient; hence viscous effects must be included. Two potential methods are used, each being coupled with a calculation of the boundary layer developed downstream of the cavity. So, an "open cavity" numerical model, as it is called, was developed and tested with two types of foil: a NACA classic foil and a foil of which the profile is obtained performing an inverse calculation on a propeller blade test section. On the other hand, under noncavitating conditions, for each method, the results are compared with the results obtained by the Navier-Stokes solver "FLUENT." The cavitating flow configurations presented herein were carried out using the small hydrodynamic tunnel at Bassin d'Essais des Carènes [Val de Reuil, France]. The results obtained by the two methods are compared with experimental measurements.

Three-Dimensional Effects on Slamming Loads

2021 ◽  
Author(s):  
Shan Wang ◽  
C. Guedes Soares
Keyword(s):  
3D Model ◽  
Numerical Solutions ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
The Body ◽  
Navier Stokes ◽  
Courant Number ◽  
Dimensional Effects ◽  
Coefficient Distribution ◽  
Experimental Values

Abstract Three-dimensional effects on slamming loads predictions of a ship section are investigated numerically using the unsteady incompressible Reynolds-Average Navier-Stokes (RANS) equations and volume of fluid (VOF) method, which are implemented in interDyMFoam solver in open-source library OpenFoam. A convergence and uncertainty study is performed considering different resolutions and constant Courant number (CFL) following the ITTC guidelines. The numerical solutions are validated through comparisons of slamming loads and motions between the CFD simulations and the available experimental values. The total slamming force and slamming pressures on a 2D ship section and the 3D model are compared and discussed. Three-dimensional effects on the sectional force and the pressures are quantified both in transverse and longitudinal directions of the body considering various entry velocities. The non-dimensional pressure coefficient distribution on the 3D model is presented.

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