Nowadays, a lot of energy is spent for air-conditioning in the cities for offices and private-housing. A good knowledge of the urban micro climate around the buildings could allow using the wind for natural air ventilation. UrbaWind is an automatic computational fluid dynamics (CFD) code developed in 2008 by Meteodyn to model the wind in urban environment. A module was recently added to assess the buildings air ventilation. First UrbaWind integrates climatology according to the geographic location of the site. Giving the influence of the shape and urban planning on the wind behaviors, UrbaWind solves the equations of fluid mechanics with a specific model which allows taking into account the urban environment effects such as vortexes, venturi or wise effects. Finally, the software is able to compute the wind flow inside each internal volume according to the openings of the buildings.This paper presents this software that has been designed for energy engineers to optimize the energy consumption inside a building. This is also an important tool for architects and project managers to make a building. The shape of the building as well as the orientation and the location of the openings can be designed with the awareness of the wind-induced natural air ventilation.
Novel Adaptive Controller for PMSG Driven Wind Turbine To Improve Power Syste...IJMERJOURNAL
ABSTRACT: This paper describes the behavior of a permanent magnet synchronous generator (PMSG) driven by wind turbine. The proposed conversion system is a good alternative due to its high efficiency and reliability. Electrolytic capacitors are not required in this type of converter and the voltage in the DC-link as well as the generated reactive power can be dynamically modified according to the wind velocity. The adaptive control strategy uses an adaptive PI which is self-tuned based on a linear approximation of the power system calculated at each sample time. Space vector technique for grid side inverter for transformer less integration of generator and a pulse-width modulated current source converter. A model reference is also projected in order to reduce the post-fault voltages. Simulation results prove the advantages of the proposed control. A MATLAB computer simulation study was undertaken and results on PWM-CSC are presented
UrbaWind, a Computational Fluid Dynamics tool to predict wind resource in urb...Stephane Meteodyn
Computational Fluid Dynamics (CFD) is already a necessary tool for modeling the wind over complex country side terrains. Indeed to maximize energetic yield and optimize the costs, before installing the wind systems, a good knowledge of wind characteristics at the site is required. Meteodyn has developed UrbaWind, which is an automatic CFD software for computing the wind between buildings for small wind turbines. Compared to rural open spaces, the geometry in urban areas is more complex and unforeseeable. The effects created by the buildings, such as vortexes at the feet of the towers, Venturi effect or Wise effect, make the modeling of urban flows more difficult. The model used in UrbaWind allows to take these effects into account by solving the equations of Fluid Mechanics with a specific model which can represent the turbulence and the wakes around buildings as well as the porosity of the trees. In order to validate UrbaWind’s results, different study cases proposed by the Architectural Institute of Japan have been set up. The three selected cases have an ascending complexity, from the simple block to the complete rebuilding of a quarter of the Japanese city of Niigata. The results validate UrbaWind as well for theoretical cases as for real cases by offering a minor error margin on the wind speed prediction.
http://meteodyn.com/en
International Refereed Journal of Engineering and Science (IRJES)irjes
a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
Design and performance evaluation of a solar tracking panel of single axis in...IJECEIAES
This paper presents the mechanical design of a single axis solar tracking system, as well as the electronic design of a system that to record in real time the electric power delivered by the solar tracker and to evaluate its performance. The interface was developed in Labview and it compares the power supplied by the tracker with the power supplied by static solar panel of the same characteristics. The performance is initially simulated using Pv-Syst software, and later validated with the data obtained by the interface. As a result, the use of the solar tracker increases the power delivered by a minimum of 19%, and it can go as high as 47.84%, with an average in increase in power of 19.5% in the monthly energy production. This experimental result was compared with the simulation by Pv-Syst software and shows a difference of only 2.5%, thus validating the reliability of the simulation. This behavior pattern coincides with previous studies carried out for equatorial latitudes.
This paper aims to implement a new contribution for sliding mode control (SMC) of permanent magnet synchronous generator (PMSG) for wind systems conversion with track the maximum power point tracking (MPPT) power. The SMC is a very popular approach due to its robustness in dealing with the non-linear electrical power systems. In this work, the application of the SMC control is by using the non lineare model of the PMSG. The objective of this work is to control stator active and stator reactive power, and the voltage-frequency for a better injection into the network. The results obtained show better robustness.
Novel Adaptive Controller for PMSG Driven Wind Turbine To Improve Power Syste...IJMERJOURNAL
ABSTRACT: This paper describes the behavior of a permanent magnet synchronous generator (PMSG) driven by wind turbine. The proposed conversion system is a good alternative due to its high efficiency and reliability. Electrolytic capacitors are not required in this type of converter and the voltage in the DC-link as well as the generated reactive power can be dynamically modified according to the wind velocity. The adaptive control strategy uses an adaptive PI which is self-tuned based on a linear approximation of the power system calculated at each sample time. Space vector technique for grid side inverter for transformer less integration of generator and a pulse-width modulated current source converter. A model reference is also projected in order to reduce the post-fault voltages. Simulation results prove the advantages of the proposed control. A MATLAB computer simulation study was undertaken and results on PWM-CSC are presented
UrbaWind, a Computational Fluid Dynamics tool to predict wind resource in urb...Stephane Meteodyn
Computational Fluid Dynamics (CFD) is already a necessary tool for modeling the wind over complex country side terrains. Indeed to maximize energetic yield and optimize the costs, before installing the wind systems, a good knowledge of wind characteristics at the site is required. Meteodyn has developed UrbaWind, which is an automatic CFD software for computing the wind between buildings for small wind turbines. Compared to rural open spaces, the geometry in urban areas is more complex and unforeseeable. The effects created by the buildings, such as vortexes at the feet of the towers, Venturi effect or Wise effect, make the modeling of urban flows more difficult. The model used in UrbaWind allows to take these effects into account by solving the equations of Fluid Mechanics with a specific model which can represent the turbulence and the wakes around buildings as well as the porosity of the trees. In order to validate UrbaWind’s results, different study cases proposed by the Architectural Institute of Japan have been set up. The three selected cases have an ascending complexity, from the simple block to the complete rebuilding of a quarter of the Japanese city of Niigata. The results validate UrbaWind as well for theoretical cases as for real cases by offering a minor error margin on the wind speed prediction.
http://meteodyn.com/en
International Refereed Journal of Engineering and Science (IRJES)irjes
a leading international journal for publication of new ideas, the state of the art research results and fundamental advances in all aspects of Engineering and Science. IRJES is a open access, peer reviewed international journal with a primary objective to provide the academic community and industry for the submission of half of original research and applications.
Design and performance evaluation of a solar tracking panel of single axis in...IJECEIAES
This paper presents the mechanical design of a single axis solar tracking system, as well as the electronic design of a system that to record in real time the electric power delivered by the solar tracker and to evaluate its performance. The interface was developed in Labview and it compares the power supplied by the tracker with the power supplied by static solar panel of the same characteristics. The performance is initially simulated using Pv-Syst software, and later validated with the data obtained by the interface. As a result, the use of the solar tracker increases the power delivered by a minimum of 19%, and it can go as high as 47.84%, with an average in increase in power of 19.5% in the monthly energy production. This experimental result was compared with the simulation by Pv-Syst software and shows a difference of only 2.5%, thus validating the reliability of the simulation. This behavior pattern coincides with previous studies carried out for equatorial latitudes.
This paper aims to implement a new contribution for sliding mode control (SMC) of permanent magnet synchronous generator (PMSG) for wind systems conversion with track the maximum power point tracking (MPPT) power. The SMC is a very popular approach due to its robustness in dealing with the non-linear electrical power systems. In this work, the application of the SMC control is by using the non lineare model of the PMSG. The objective of this work is to control stator active and stator reactive power, and the voltage-frequency for a better injection into the network. The results obtained show better robustness.
Torque estimator using MPPT method for wind turbines IJECEIAES
In this work, we presents a control scheme of the interface of a grid connected Variable Speed Wind Energy Generation System based on Doubly Fed Induction Generator (DFIG). The vectorial strategy for oriented stator flux GADA has been developed To extract the maximum power MPPT from the wind turbine. It uses a second order sliding mode controller and Kalman observer, using the super twisting algorithm. The simulation describes the effectiveness of the control strategy adopted.For a step and random profiles of the wind speed, reveals better tracking and perfect convergence of electromagnetic torque and concellation of reactive power to the stator. This control limits the mechanical stress on the tansmission shaft, improves the quality of the currents generated on the grid and optimizes the efficiency of the conversion chain.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Economic Selection of Generators for a Wind Farmijeei-iaes
The selection suitable generator for wind turbines will be done based on technical criteria and priorities of the project. In this paper, a method for determining the type of wind turbine generator with an example is explained. In the paper, for a 10kW wind turbine, two generators have been proposed. The first case is a squirrel-cage asynchronous generator coupled to the turbine through the gearbox and directly connected to three phase output. Other PM generators that are directly coupled to the turbine and it is connected to the grid using the inverter. The results show that according to wind conditions, a 10kW permanent magnet generator is more advantageous in terms of energy production.
New wind computation urban areas: UrbaWind 2.2 releaseStephane Meteodyn
New features of UrbaWind: automatic CFD software to compute the wind in any complex urban area. Compatible with thermal simulation software, read all climatological data, new porosity classification, air change rate statistics improved, better visualisation
Test different neural networks models for forecasting of wind,solar and energ...Tonmoy Ibne Arif
In this project work, a multi-step deep neural network is used to forecast power generation and load demand for a short-term time frame. The data or feature vectors that have been used to predict the target, is a sequential time series sequence. In this project, a Recurrent Neural Network has been used in combination with a convolutional neural network to have a better forecasting model for the Windpark, Solar park and Loadpark datasets. Moreover, the forecasting performance of Feedforward neural network and Long Short Term Memory also has been compared. The whole project work has divided into two parts, in the first approach the raw dataset has been divided into a train, test split and no previous step data have been used. In the second step whole raw dataset has been divided into test, train and validation split. Additionally, current and seven previous time steps data has been fed into the model.
This article addresses the problem of controlling an overall wind energy conversion system (WECS) formed by a wind turbine connected to the grid via a doubly fed introduction generator (DFIG) and an AC/DC/AC converter. The main control objectives are fourfold: (i) designing an output feedback speed controller that makes the DFIG rotate at the optimal value delivered by the MPPT strategy, (ii) controlling the stator reactive power so as to be null, (iii) guaranteeing the DC-link voltage in the grid side converter to be at a given constant value, (iv) ensuring a unitary power factor. A high gain observer is synthesized, in order to provide estimated values of the mechanical variables. To achieve the control objectives, a sliding mode controller involving the mechanical observer is designed. The performance of the system configuration based on the 2MW-DFIG with the proposed controller is evaluated by a numerical simulation under a realistic wind profile using MATLAB/SIMULINK/SimPowerSystems environment.
A simplified method of designing a phase lead compensator to improve the m-s-...eSAT Journals
Abstract In this study, based on the unconstrained third order shear deformation theory (UTSDT), numerical analysis of an axisymmetric bending and stresses of circular plate are investigated. The material properties are considerd to graded through the thickness of the verticlecoordinate, and follow a simple power of volume fraction of the constituents.governing equations are derived and DQM is used as an efficient numerical method for solving the differential equations.Two types of boundary conditions under the influence of the bending and body force are studied. The validation of the results is done by a comparison with another study ,which available in the literature and found good agreement between two studies. Index Terms:bending,shearstress,circularplate,UTSDT,GDQM.
Fans Vs. Natural Ventilation: Cost Comparisonilachut
Compare the total costs of installing powered fans vs. a natural ventilation system. Discover how much you can save on product and installation costs by choosing a natural ventilator
Torque estimator using MPPT method for wind turbines IJECEIAES
In this work, we presents a control scheme of the interface of a grid connected Variable Speed Wind Energy Generation System based on Doubly Fed Induction Generator (DFIG). The vectorial strategy for oriented stator flux GADA has been developed To extract the maximum power MPPT from the wind turbine. It uses a second order sliding mode controller and Kalman observer, using the super twisting algorithm. The simulation describes the effectiveness of the control strategy adopted.For a step and random profiles of the wind speed, reveals better tracking and perfect convergence of electromagnetic torque and concellation of reactive power to the stator. This control limits the mechanical stress on the tansmission shaft, improves the quality of the currents generated on the grid and optimizes the efficiency of the conversion chain.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Economic Selection of Generators for a Wind Farmijeei-iaes
The selection suitable generator for wind turbines will be done based on technical criteria and priorities of the project. In this paper, a method for determining the type of wind turbine generator with an example is explained. In the paper, for a 10kW wind turbine, two generators have been proposed. The first case is a squirrel-cage asynchronous generator coupled to the turbine through the gearbox and directly connected to three phase output. Other PM generators that are directly coupled to the turbine and it is connected to the grid using the inverter. The results show that according to wind conditions, a 10kW permanent magnet generator is more advantageous in terms of energy production.
New wind computation urban areas: UrbaWind 2.2 releaseStephane Meteodyn
New features of UrbaWind: automatic CFD software to compute the wind in any complex urban area. Compatible with thermal simulation software, read all climatological data, new porosity classification, air change rate statistics improved, better visualisation
Test different neural networks models for forecasting of wind,solar and energ...Tonmoy Ibne Arif
In this project work, a multi-step deep neural network is used to forecast power generation and load demand for a short-term time frame. The data or feature vectors that have been used to predict the target, is a sequential time series sequence. In this project, a Recurrent Neural Network has been used in combination with a convolutional neural network to have a better forecasting model for the Windpark, Solar park and Loadpark datasets. Moreover, the forecasting performance of Feedforward neural network and Long Short Term Memory also has been compared. The whole project work has divided into two parts, in the first approach the raw dataset has been divided into a train, test split and no previous step data have been used. In the second step whole raw dataset has been divided into test, train and validation split. Additionally, current and seven previous time steps data has been fed into the model.
This article addresses the problem of controlling an overall wind energy conversion system (WECS) formed by a wind turbine connected to the grid via a doubly fed introduction generator (DFIG) and an AC/DC/AC converter. The main control objectives are fourfold: (i) designing an output feedback speed controller that makes the DFIG rotate at the optimal value delivered by the MPPT strategy, (ii) controlling the stator reactive power so as to be null, (iii) guaranteeing the DC-link voltage in the grid side converter to be at a given constant value, (iv) ensuring a unitary power factor. A high gain observer is synthesized, in order to provide estimated values of the mechanical variables. To achieve the control objectives, a sliding mode controller involving the mechanical observer is designed. The performance of the system configuration based on the 2MW-DFIG with the proposed controller is evaluated by a numerical simulation under a realistic wind profile using MATLAB/SIMULINK/SimPowerSystems environment.
A simplified method of designing a phase lead compensator to improve the m-s-...eSAT Journals
Abstract In this study, based on the unconstrained third order shear deformation theory (UTSDT), numerical analysis of an axisymmetric bending and stresses of circular plate are investigated. The material properties are considerd to graded through the thickness of the verticlecoordinate, and follow a simple power of volume fraction of the constituents.governing equations are derived and DQM is used as an efficient numerical method for solving the differential equations.Two types of boundary conditions under the influence of the bending and body force are studied. The validation of the results is done by a comparison with another study ,which available in the literature and found good agreement between two studies. Index Terms:bending,shearstress,circularplate,UTSDT,GDQM.
Fans Vs. Natural Ventilation: Cost Comparisonilachut
Compare the total costs of installing powered fans vs. a natural ventilation system. Discover how much you can save on product and installation costs by choosing a natural ventilator
Natural Ventilation & Lighting brochure »
Our Natural Ventilation & Lighting brochure is an introduction to the various systems we offer, detailing the health benefits, suitable applications, sectors, product information and technical specifications for each of the various systems and any complementary products available. It also includes a selection of case studies.
Mechanical ventilation such as an energy recovery ventilator (ERV) or a heat recovery ventilator (HRV) provides a solution to a number of issues presented by natural ventilation. Proper ventilation is a critical consideration for homes and buildings. Poor ventilation can cause a buildup in indoor air pollutants like dust, pollen, mold, and household chemicals and lead to a lower living standard and poorer health of the building’s occupants.
Dancing Rabbit Ecovillage. This introduction is a tour of the village through pictures of daily life. Solar panels, permaculture agriculture, timber frame homes, wind turbines, consensus decision making, strawbale construction, eating cooperatives, swimming in the pond...it's all there.
Example of natural air ventilation using CFD modellingStephane Meteodyn
Urbawind is a CFD software dedicated to quantify the natural air ventilation of buildings.
Such tool is useful to design green buildings where wind is used to improve the indoor thermal comfort with cross ventilation.
Objective is to determine project improvements from indoor thermal comfort and energy saving points of view.
For example, for a site study of natural air ventilation induced by wind in urban places, you can obtain:
– Mapping of wind speed and pressure
– Assess the natural air ventilation thanks to the computation of the air exchange rate
– Optimise the positions of openings according to the micro climatology
go to : http://meteodyn.com/en/logiciels/cfd-wind-pedestrian-comfort-safety-urbawind-software/#modules-tab
Assessment of the natural air ventilation of buildings in urban area with the...Stephane Meteodyn
Nowadays, a lot of energy is spent for air-conditioning in the cities for offices and private-housing. A good knowledge of the urban climatology around the buildings allows using the wind for natural air ventilation. A combined approach based on a Computational fluid dynamics code (CFD) that models the wind in urban environment and on air network tool was developed to assess quickly the natural ventilation of buildings in urban area. The aerodynamic tool is a CFD-Network software named "UrbaWind which performs calculation of the outdoor wind combined with a macroscopic network method for the evaluation of the mass flow rates through the openings. Results depend on the external wind conditions, taking into account the local wind climatology.
Giving the influence of the shape and the disposition of the buildings on the wind behaviors, CFD software solves the equations of fluid mechanics with a specific model which allows taking into account the urban environment effects such as vortexes, venturi or wise effects etc…. Finally, the software is able to compute the air mass flow rate inside each internal volume depending on the opening's behaviors attached to the wall building.
The mass flow rates across air inlets and openings, as well as the pressure fields on the building envelope are computed for every wind incidence, considering a wind reference velocity. The local climatology is introduced to deliver statistical data useful to assess the energy consumption and the thermal comfort (air exchange rate, indoor velocity).
Through many architectural and urban design projects, Meteodyn will introduce during this session the characteristics of the software UrbaWind and the results delivered to the design teams.
Modelling Natural Ventilation in IES-VE: Case studies & Research OutlookIES VE
Daniel Coakley of IES spoke on the topic of “Modelling Natural ventilation in the IESVE: Case studies & Research Outlook” at a half day seminar on 20th April 2016, organised by Cork Institute of Technology (CIT), for researchers, designers, engineers & architects.
This topic explains the importance of ventilation in a building. Identification on types of ventilation and air conditioning system, methods of installation of air conditioning system and its components.
Large cities are engaged in reducing CO2 emissions with the help of renewable energy. The aim of this study is to assess wind energy production over the 640 km² of the Metropolitan Area of Barcelona (AMB in Catalan) in order to set up small wind turbines to be connected to the smart grid. Buildings
will create wind acceleration, recirculation areas, blocking effects. CFD software Urbawind models the wind inside this complex urban canopy. The work has been commissioned by the Sustainability Plan and the Environmental Services of the Metropolitan Area of Barcelona. WWW.METEODYN.COM
Numerical tools dedicated to wind engineering MeteodynStephane Meteodyn
This paper presents a global methodology to compute wind flow in complex urban areas in order to assess wind pedestrian comfort, wind energy, wind safety or natural
ventilation potential. The numerical tool presented here is composed of a CFD software suite covering both regional scale (20 km) and urban scale (1km), and able to model the wind in any complex terrains and in large urban environments. Examples are presented in the paper in order to show the advantages of the methodology for urban designers...
Simulations Of Unsteady Flow Around A Generic Pickup Truck Using Reynolds Ave...Abhishek Jain
Above Research Paper can be downloaded from www.zeusnumerix.com
The research paper aims to replicate the wind tunnel test of General Motors pick-up truck using CFD analysis. The pickup is a blunt body and simulation reveals vortex shedding from the edges of the vehicle downstream. The unsteadiness of this phenomenon is seen in the oscillation of residue. The paper shows matching of velocity magnitude downstream of the vortex. Authors - Bahram Khalighi (GM, USA), Basant Gupta et al Zeus Numerix.
A combined cfd network method for the natural air ventilation - icwe13Stephane Meteodyn
The purpose of this work is to provide to designers a software devoted to calculate the wind on the buildings (CFD tools), to compute with a macroscopic method the exchange rate incoming to the building for each wind characteristics (incidence and velocity magnitude), and finally to give natural air ventilation statistics according to the wind statistics of the urban place considered. UrbaWind is an automatic computational fluid dynamics (CFD) code developed by Meteodyn to model the urban micro climate. In this context, the software Urbawind was upgraded to introduce the natural cross ventilation. The interface allows the computation of the flow rate incoming and outcoming across every air inlets and windows. The software first computes the pressure fields on the building envelope for every wind incidence with the wind reference velocity, then evaluates air exchanges rate for each climatology event and finally builds statistical data of the air exchanges useful for designers. The first step concerned a simple case, as detached house far from neighbor buildings, without internal fittings.The main objectives of this study are : 1 Extend the method to real complex buildings with many rooms and urban environment by introducing the climatology, 2 Include the indoor walls and doors into a simple network tool connected to the CFD software, 3 Produce data useful to assess the indoor thermal comfort: air change rate, indoor velocity.
Validations and applications of a CFD tool dedicated to wind assessment in ur...Stephane Meteodyn
UrbaWind is a CFD code developed by Meteodyn especially dedicated to urban wind applica-tions with an automatic meshing and boundary conditions set-up. The paper shows validations by comparisons with experimental data proposed by the Architectural Institute of Japan (Tominaga et al., 2008). The first selected case is a wind-tunnel experiment of wind past a group of blocks, and the second one is a field experiment inside a quarter Niigata (Japan). Three examples of ap-plication in the outdoor comfort assessment are presented: A pool deck of Mosaic Houston (Tex-as), Chambéry Hospital (France), Saint-Brieuc district (France).
Offset effect on the S-Bend structure losses and optimization of its size for...IJECEIAES
The S-Bend structures are heavily exploited to join optical components. Reducing the power loss caused by the curve is the main objective in the design step of these components. However integrated optical circuits require S-Bend waveguide to be low loss and compact sized. In this paper, we present a contribution to link the curved structure to the straight waveguide by using the simulated bend function available in the Beam propagation tool of the Rsoft commercial software package. Simulation results confirm that this approach allows a reduction of the size of the curved structure with offset with relatively minimum of losses for photonic field.
International journal of engineering and mathematical modelling vol1 no1_2015_1IJEMM
The degradation of the weather conditions is dangerous for driving and should incite drivers to reduce the car speed. The present work solves this problem of the speed limit in city road and highway by changing automatically the authorized speed with the weather conditions.
The new developed stand-alone speed limit road sign is intelligent and is capable to analyze the weather context using sensors, and to display the most adapted speed limit according to the surrounding environment. Several scenarios have been proposed to develop a pre industrialized prototype and to analyze them according to different criteria (cost, consumption, endurance and reliability). In addition, the system is an autonomous stand alone and uses the solar energy as source of supply. The pre-industrial prototype of the system was successfully achieved. However to develop a "low cost" system a new concept of meteorological sensors was done, for the low consumption of the display we use the LED (light emitting diode) components.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
At present, with the development of wind power project in China, there are more and more projects located at the complex terrain and complex environment. At the same time, since the large planned area of project, the complex mountain area, and limited number of met mast, even without met mast, in order to the reliable development of the wind power project, it is important that how to do the wind resource assessment without actual measurement wind data and other conditions such as less reliable wind data, and the met mast was not considered representative. This paper will use the atmospheric model to do mesoscale simulation calculation of wind resources, and then combine with CFD technology to downscaling computation to get high resolution wind power assessment result. Finally, in order to confirm the validity of this application in the actual project, the comparison between calculation values and measurement values is carried out. The verification result through the actual data of different met mast shows that the wind resource assessment method which combines the CFD and mesoscale technologies is reliable. The main contribution of the article is to provide the reference model and approach for regional planning and large scale wind resource assessment when there isn’t enough adequate and effective wind data.
Validations and applications of a CFD tool dedicated to wind assessment in ur...Stephane Meteodyn
UrbaWind is a CFD code developed by Meteodyn especially dedicated to urban wind applica-tions with an automatic meshing and boundary conditions set-up. The paper shows validations by comparisons with experimental data proposed by the Architectural Institute of Japan (Tominaga et al., 2008). The first selected case is a wind-tunnel experiment of wind past a group of blocks, and the second one is a field experiment inside a quarter Niigata (Japan). Three examples of ap-plication in the outdoor comfort assessment are presented: A pool deck of Mosaic Houston (Tex-as), Chambéry Hospital (France), Saint-Brieuc district (France).
Feasibility of Substitution of the Conventional Street Lighting Installation ...IJECEIAES
In this work, we present a technical and economic study of the solar powered street lighting system of a municipality in the south of Morocco. The state of the conventional street lighting system is first analyzed in a substation of street lighting. Then a sizing method is applied to the photovoltaic installation in the testing area. A financial study, by comparison between conventional and PV-based lighting, is carried out showing the feasibility of the PV street lighting.).
A low-power 2-bit/step operation technique is proposed which uses dynamic threshold configuring comparator instead of multiple digital-to-analog converters (DACs). Power and area overhead is minimized by successively activated comparators. The comparator threshold is configured by simple Vcm biased current source, which keep the ADC free from power supply variations over 10%. To implement power efficient and high performance analog-to-digital converters the designers are urged to design an optimized dual tail comparator. In this paper, It is shown that in the proposed dual tail comparator both the power and delay time is significantly reduced.
FINITE ELEMENT ANALYSIS OF RIGID PAVEMENT USING EVERFE2.24& COMPARISION OF RE...civej
In this study analysis of plain cement concrete pavement was done with 3-D mechanistic FEM computer
programme EVERFE2.24. This programme was developed by Bill David, University of Maine,USA. Rigid
pavement is modelled as a flat slab with DLC as base course and subgrade beneath it.
Stresses in rigid pavement at critical location was calculated due to combined effect of axle load and
environmental factor.These results are compared with IRC58-2015&2002.The disparity between results
are analysed and plotted on graph.
This study finds that stressesgiven by IRC58-2015 is up to 42% less than that given by IRC58-2002, and
stresses given by EverFE2.24 is nearly same as given by IRC58-2002.italso highlighted some issues related
to new code of design i.e. IRC58-2015.
Similar to Integration of the natural cross ventilation in the CFD software UrbaWind (20)
Wind computation in urban areas: UrbaWind 3.0 new featuresStephane Meteodyn
UrbaWind new features: a repository of wind comfort criteria across the world, new turbulence model bringing results closer to wind tunnel's, convergence improved.
The software is compatible with thermal simulation software and read all climatological data.
During 9th Intenational Conference on Urban Climate - July 2015, Ulbaterre, CSTB and Meteodyn presented : Bonifacio has to face strong wind all the year long and high speed wind. Around 2 millions tourists visit Bonifacio each year. Tourism project : museum, new hôtel, baby nursery, housing and activities. Wind is a stake of urban comfort and city branding. Wind study and solutions. www.meteodyn.com
WInd resource assessment in urban areas for sustainable developmentStephane Meteodyn
The paper presents a numerical methodology to assess wind pedestrian comfort and natural ventilation.UrbaWind is an automatic computational fluid dynamics code. It was developed to model the wind in urban environments. The turbulence modelling, namely the dependance of turbulence length on the distance from wall, and the model constants were calibrated in order to reproduce with good agreements flow separation around builings walls. Numerical results match well with the expriments: separation patterns, pressure field on wall, wind speed in dense urban area. Two examples are presented at the end of the paper in order to show the advantages of the methodology for urban designers.
Wind-induced pressure coefficients on buildings dedicated to air change rate ...Stephane Meteodyn
The paper presents a numerical methodology to assess the natural ventilation. UrbaWind is an automatic computational fluid dynamics code. It was developed to model the wind in urban environments. The turbulence modelling, namely the dependence of turbulence length on the distance from wall, and the model constants were calibrated in order to reproduce with good agreements flow separation around buildings walls and pressure coefficient field on façades. Numerical results match well with the experiments: separation patterns and pressure field on walls in dense urban areas. Examples are presented at the end of the paper in order to show the advantages of the methodology for urban designers as they need pressure coefficients to assess the air change rate of buildings...
Pedestrian wind comfort in urban area with numerical toolsStephane Meteodyn
Winds in urban area are strongly diffrent from those nearby meteorological stations. Numerical tools bring accurate wind comfort assessment in new urban projects to wind engineering team and sustainable city development consultants.
Atmospheric turbulent layer simulation for cfd unsteady inlet conditionsStephane Meteodyn
The aim of this work is to bridge the gap between experimental approaches in wind tunnel testing and numerical computations, in the field of structural design against strong winds. This paper focuses on the generation of an unsteady flow field, representative of a natural wind field, but still compatible with CFD inlet requirements. A simple and “naïve” procedure is explained, and the results are successfully compared to some standards.
Exemples of building design, wind urban planning, natural air ventilation and wind pedestrian comfort studies. Site climatology wih UrbaWind, wind modeling and wind potential software.
Calibrating a CFD canopy model with the EC1 vertical profiles of mean wind sp...Stephane Meteodyn
For some projects, applying the basic rules of EC1 is not sufficient, and it is required to get a more accurate estimation of the wind speed on the construction site. This can be done by using computational fluid dynamics codes which have the advantage, both to take into account of the terrain inhomogeneity and to calculate 3D orographic effects. In this way, the orography and roughness effects are coupled as they are in the real world. However, applying CFD computations must be in coherence with EC1 code. Then it is necessary to calibrate the ground friction for low roughness terrains as well as the drag force and turbulence production in case of high roughness lengths due to the presence of a canopy (forests or built areas). That is the condition for such methods to be commonly used and agreed by Building Control Officers. In this mind, TopoWind has been developed especially for wind design applications and can be a very useful, practical and objective tool for wind design engineers. The canopy model implemented in TopoWind has been calibrated in order to get the mean wind and turbulence profiles as defined in the EC1 for standard terrains. In this way, TopoWind computations satisfy the continuity between the EC1 values for homogeneous terrains and the more complex cases involving inhomogeneous roughness or orographic effects
Example of Pedestrian Comfort & Safety study using CFD modelling software Urb...Stephane Meteodyn
This is an example of numerical modelling of the urban climate.
Objective of the study is to bring more quality to outdoor living spaces through studies of climate comfort, to improve the projects according to the outdoor pedestrian comfort.
For example, for a site study of DISCOMFORT FRECUENCIES, approach is to assess:
Mappings of wind speed-up for prevailing wind directions at the pedestrian height (1.5 m above the ground).
Mappings of frequencies of the gust speeds exceeding the speed of 3,6m/s at the pedestrian height (1.5 m above the ground).
http://meteodyn.com/en/logiciels/cfd-wind-pedestrian-comfort-safety-urbawind-software/#modules-tab
Combined CFD-Mean energy balance methode to thermal comfort assessment of bui...Stephane Meteodyn
The paper presents combined approaches dedicated to assess the thermal comfort in a tropical climate. UrbaWind, an automatic computational fluid dynamics code, was developed to model the wind in urban environments. A module was recently added to assess the buildings’s natural air ventilation. The simple thermal method Batipei, allows computing the mean overheating inside the building by considering the envelope thermal behaviours, the outdoor thermal conditions and the air exchange rate. Finally, an architectural case of urban renovation of old buildings in La Reunion Island is presented as an example of the using of the combined approaches for urban planning.
The decision making process related to urban areas synthetizes a lot of data taking into account
numerous parameters. The indicators produced from simulations or data mining on 3D city models (3DCM)
can be a great help into these decision-making processes. The problem is to acquire and process the 3DCM
in order to produce these indicators at city scale. The EnVIE project proposes a framework to perform the
acquisition of 3DCM and then to produce 3D or 2D metadata on these models. As several city councils have
been interviewed in the scope of the project to describe their real needs, the computed metadata are directly
usable into the decision-making process. The main contribution of this framework is to merge existing
techniques to build a pipeline allowing to compute lighting and wind simulation, and to extract socioeconomic
metadata with data-mining techniques. This on-going work builds a link between indicators at
the building scale and 2D indicators at larger scale from GIS, and therefore is a step towards an indicator
production process at full-scale range.
WRI’s brand new “Food Service Playbook for Promoting Sustainable Food Choices” gives food service operators the very latest strategies for creating dining environments that empower consumers to choose sustainable, plant-rich dishes. This research builds off our first guide for food service, now with industry experience and insights from nearly 350 academic trials.
Natural farming @ Dr. Siddhartha S. Jena.pptxsidjena70
A brief about organic farming/ Natural farming/ Zero budget natural farming/ Subash Palekar Natural farming which keeps us and environment safe and healthy. Next gen Agricultural practices of chemical free farming.
UNDERSTANDING WHAT GREEN WASHING IS!.pdfJulietMogola
Many companies today use green washing to lure the public into thinking they are conserving the environment but in real sense they are doing more harm. There have been such several cases from very big companies here in Kenya and also globally. This ranges from various sectors from manufacturing and goes to consumer products. Educating people on greenwashing will enable people to make better choices based on their analysis and not on what they see on marketing sites.
Willie Nelson Net Worth: A Journey Through Music, Movies, and Business Venturesgreendigital
Willie Nelson is a name that resonates within the world of music and entertainment. Known for his unique voice, and masterful guitar skills. and an extraordinary career spanning several decades. Nelson has become a legend in the country music scene. But, his influence extends far beyond the realm of music. with ventures in acting, writing, activism, and business. This comprehensive article delves into Willie Nelson net worth. exploring the various facets of his career that have contributed to his large fortune.
Follow us on: Pinterest
Introduction
Willie Nelson net worth is a testament to his enduring influence and success in many fields. Born on April 29, 1933, in Abbott, Texas. Nelson's journey from a humble beginning to becoming one of the most iconic figures in American music is nothing short of inspirational. His net worth, which estimated to be around $25 million as of 2024. reflects a career that is as diverse as it is prolific.
Early Life and Musical Beginnings
Humble Origins
Willie Hugh Nelson was born during the Great Depression. a time of significant economic hardship in the United States. Raised by his grandparents. Nelson found solace and inspiration in music from an early age. His grandmother taught him to play the guitar. setting the stage for what would become an illustrious career.
First Steps in Music
Nelson's initial foray into the music industry was fraught with challenges. He moved to Nashville, Tennessee, to pursue his dreams, but success did not come . Working as a songwriter, Nelson penned hits for other artists. which helped him gain a foothold in the competitive music scene. His songwriting skills contributed to his early earnings. laying the foundation for his net worth.
Rise to Stardom
Breakthrough Albums
The 1970s marked a turning point in Willie Nelson's career. His albums "Shotgun Willie" (1973), "Red Headed Stranger" (1975). and "Stardust" (1978) received critical acclaim and commercial success. These albums not only solidified his position in the country music genre. but also introduced his music to a broader audience. The success of these albums played a crucial role in boosting Willie Nelson net worth.
Iconic Songs
Willie Nelson net worth is also attributed to his extensive catalog of hit songs. Tracks like "Blue Eyes Crying in the Rain," "On the Road Again," and "Always on My Mind" have become timeless classics. These songs have not only earned Nelson large royalties but have also ensured his continued relevance in the music industry.
Acting and Film Career
Hollywood Ventures
In addition to his music career, Willie Nelson has also made a mark in Hollywood. His distinctive personality and on-screen presence have landed him roles in several films and television shows. Notable appearances include roles in "The Electric Horseman" (1979), "Honeysuckle Rose" (1980), and "Barbarosa" (1982). These acting gigs have added a significant amount to Willie Nelson net worth.
Television Appearances
Nelson's char
Integration of the natural cross ventilation in the CFD software UrbaWind
1. 1
UrbaWind, a Computational Fluid Dynamics tool to predict wind resource
in urban area
Karim FAHSSISa
, Guillaume DUPONTa
, Pierre LEYRONNASa
a
Meteodyn, Nantes, France
Presenting Author: Karim.fahssis@meteodyn.com, Tel: +33 240 71 05 05
Corresponding Author: Guillaume.dupont@meteodyn.com, Tel: +1 267 475 4278
Abstract:
Computational Fluid Dynamics (CFD) is already a necessary tool for modeling the wind over
complex rural terrains. In order to maximize energetic yield and optimize the costs, before
installing the wind energy systems, a good knowledge of wind characteristics on site is
required. Meteodyn has developed UrbaWind, which is an automatic CFD software for
computing the wind in urban environment for small wind turbines.
Compared to rural open spaces, the geometry in urban areas is more complex and
unforeseeable. The effects created by the buildings, such as vortexes at the feet of the towers,
Venturi effect or Wise effect, make the modeling of urban flows more difficult. The model
used in UrbaWind allows to take these effects into account by solving the equations of Fluid
Mechanics with a specific model that can represent the turbulence and the wakes around
buildings as well as the porosity of the trees and the effects of the ground roughness (asphalt,
water or grass).
In order to validate UrbaWind‟s results, different study cases proposed by the Architectural
Institute of Japan have been set up. The three selected cases have an ascending complexity,
from the simple block to the complete rebuilding of a quarter of the Japanese city of Niigata.
The results validate UrbaWind as well for theoretical cases as for real cases by offering a
minor error margin on the wind speed prediction.
Keywords: Wind modeling, CFD, urban wind energy
1.1 INTRODUCTION
In order to validate UrbaWind‟s results, different study cases based on practical uses proposed
by the Architectural Institute of Japan [1] have been set up. The three selected cases have an
ascending complexity, from the simple block to the complete rebuilding of a quarter of the
Japanese city of Niigata. These published cases allowed to compare the computations results
of UrbaWind with the measurements of the AIJ.
Therefore, the sites have been recreated in a file format that can be used by UrbaWind and the
conditions taken for the CFD computations are as similar as possible to the experiments
conditions. The values obtained by the computations are then compared with the measured
values.
At first a graphical comparison is done by placing the points in a graph with the computed
values in ordinate and the measured values in abscise (regression line).
Statistical indicators of the results accuracy are proposed as followed:
2. 2
The error, calculated by the formula:
The determination coefficient R², which corresponds to the square of the Pearson
product-moment correlation coefficient :
This last value is the square of the covariance of the reduced centered variables. Its value is
between 0 and 1. The value 0 means a total independence between both variables.
In these equations as well as in the whole document, y corresponds to the computed values
and x to the measured values, both normalized.
In every case, results are considered for all points in a first time and only for consistent points
in a second time. For the consistent points, we exclude all the very low speed points, which
lead to the biggest error and for which a great accuracy is not required when considering the
installation of wind turbines. The difference between the results obtained for both all points
and consistent points is summarized in a table in the conclusion.
1.2 DESCRIPTION OF THE CFD CODE URBAWIND
1.2.1 The Equations
UrbaWind solves the equations of Fluid Mechanics, i.e. the averaged equations of mass and
momentum conservations (Navier-Stokes equations). When the flow is steady and the fluid
incompressible, those equations become:
0
i
i
x
u
(1)
0''
iji
i
j
j
i
jij
ij
Fuu
x
u
x
u
xx
P
x
uu
(2)
The turbulent fluxes are parameterized by using the so-called turbulent viscosity. The
turbulent viscosity µ is considered as the product of a length scale by a speed scale which are
both characteristic lengths of the turbulent fluctuations. The speed scale is given as the square
root of the turbulent kinetic energy multiplied by the density. The turbulent kinetic energy is
solved using the transport equation by including the production and dissipation terms of the
turbulence where the turbulent length scale LT varies linearly with the distance at the nearest
wall (ground and buildings).
Boundary conditions are automatically generated. The vertical profile of the mean wind speed
at the computation domain inlet is given by the logarithmic law in the surface layer, and by
the Ekman function [2]. A „Blasius‟-type ground law is implemented to model frictions
(velocity components and turbulent kinetic energy) at the surfaces (ground and buildings).
3. 3
The effect of porous obstacles is modeled by introducing a sink term in the cells lying inside
the obstacle:
UUCVF d
...
(3)
1.2.2 Mesh generation
This meshing is generated by following the computed wind direction. The size of the
computation domain is automatically generated so that the minimum distance between a
building and a boundary condition is equal to 6 times the height of the highest building of the
simulation. The generated meshing is Cartesian and unstructured (using of overlapped
meshing), with automatic refinement near the ground, obstacles and of course at result points
locations.
For this study, the vertical mesh dimension around the blocks in the two first cases (simple
block and group of blocks) has been taken equal to 20 cm. The mesh dimension for the case
of City of Niigata was 50cm in the horizontal and vertical directions for the refined cells
around the buildings.
1.2.3 MIGAL-UNS Solver
1.2.3.1 DESCRIPTION
The MIGAL-UNS solver has been regularly used for some years now, and has already been
fully validated on number of academic cases [3].
MIGAL is an iterative linear equations solver which updates simultaneously the wind speed
components as well as the pressure on the whole computational domain, so-called “coupled
resolution”. This method demands more storage capacity, but it has the advantage to
dramatically increasing the convergence process.
The discretized equations linear system, is transformed via an incomplete LU decomposition
ILU(0) [4]. A preconditioner of type GMRES is used in order to increase the terms in the
main diagonal so that the solving robustness is improved.
Moreover, MIGAL uses a multi-grid procedure which consists in solving successively the
equations on different grid levels (from the finer one to the coarser one). This method
accelerates the convergence of the low frequency errors, which are known to be the limiting
factor in the convergence process. For the type of problem solved here, different tests have
shown a better convergence for the “V cycles” method than for the “W cycles” method. The
number of grid levels is automatically computed by MIGAL.
1.2.3.2 REFINEMENT STRATEGY: ALGORITHM OF AGGLOMERATION
For the multi-grid computation, MIGAL-UNS uses an agglomeration method which joins
together and agglomerates control volumes near the fine grid. This process is executed
recursively until having generated a whole sequence of coarse meshes.
Once the grid hierarchy is defined, one still has to determine how the equations are created on
the coarse meshes and how their solutions will be used in order to decrease the errors of long
wavelengths on the finest grids.
4. 4
MIGAL employs a Galerkin‟s projection method for generating the equations on the coarse
grid. This technique, so-called "Additive Correction Multi-grid" consists in generating the
equation of the coarse mesh as the sum of the equations of each corresponding fine cell. Once
the solution is obtained on the coarse grid, it is introduced by correcting the values calculated
previously on the fine grid with the calculated error.
1.3 THEORETICAL CASES: SIMPLE BLOCK AND GROUP OF BLOCKS
1.3.1 Description
The first study has been done on a square tower of 20 m high with a base of 10 m by 10 m. A
wind with a direction of 270° is applied and the computations are done on the result points
spread in two plans: a vertical plan located on x=0, which cut a tower on its middle.
The second studied site is built up of 8 blocks of 20 m of edge and an empty space in the
center. The computations are done with a wind coming from the West (blue arrow) and the
result points are located around the central empty space at two meters high, like shown in the
figure 1.
Figure 1 : Results points, z=2m
1.3.2 Results
1.3.2.1 SIMPLE BLOCK
The speed-up coefficients of the computation have been compared to the coefficients obtained
by the experimental measurements. In the following figure 2, the computed values functions
of the measured values for consistent points have been represented.
Table 1: Comparison Computations vs. Measurements for the simple block
First case – Simple Block Error R2
For all points 5.5% 0.92
For the consistent points 4.9% 0.93
5. 5
Figure 2: First case, horizontal at z=1,25m, consistent points
1.3.2.2 GROUP OF BLOCKS
The speed-up factors of the computation have been compared with the speed-up factors
obtained by the experimental measures. In the following figure 3, the computed values
functions of the measured values for consistent points have been represented.
Table 2: Comparison Computations vs. Measurements for the group of blocks
Figure 3: Second case, group of blocks, consistent points
1.3.3 Discussion
The error (5.5% in average for all points and 4.9% when selecting only the consistent points)
and the determination coefficient allow to confirm the accuracy of UrbaWind‟s results for this
first case. We can observe that the results provided by the software UrbaWind are very good
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1
Computedspeed-upfactor
Measured speed-up factor
Err = 4,9%
R² = 0,93
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1
Computedspeed-upfactor
Measured speed-up factor
Err= 5,8%
R² =0,71
First case – Group of Blocks Error R2
For all points 8.5% 0.70
For the consistent points 5.8% 0.71
6. 6
for most of the points. Only a few points are far from the linear regression curve. These
differences have several explanations.
At first most of the points correspond to low wind speeds. The differences of values are thus
proportionally bigger than for higher wind speeds. Furthermore, by visualizing these points,
we can notice that these points are in general near the walls in areas where big speed
difference can exist between points that are very near. This explains that the computation
results can be different without necessarily casting doubt on the general aspect of the
simulation.
A 2D map of the mean acceleration around the structure has been represented in the figure 4.
The worst points are indicated in red in the figure.
Figure 4: Second case, visualization
We can notice that the less consistent points are the points located in the areas where the mean
acceleration is near zero. As all the CFD models, it is in the area near the joining distance that
the results are the most difficult to reproduce. Thus, for both theoretical cases, the
underestimation of these low values does not cast doubt on the relevance of the computation.
Moreover one can observe a value of the error which is equal to 4.9% for the first case and
5.8% for the second case when selecting only the consistent points, which validates partly the
results provided by UrbaWind in both cases.
1.4 PRACTICAL CASE: QUARTER OF NIIGATA (JAPAN)
1.4.1 Description
The last study has been done in the quarter of the Japanese city of Niigata. The wind is
coming in the direction of 225° (blue arrow) and results points are placed in several random
locations as indicated in the figure 5, at two meters high.
7. 7
Figure 5: Third case, result points, z=2m
1.4.2 Results
The speed-up factors of the computation have been compared to the speed-up factors obtained
by the experimental measurements. In the following figure 6, the computed values functions
of the measured values for consistent points have been represented.
Table 3: Comparison Computations vs. Measurements for the city of Niigata
Figure 6: Third case, quarter of Niigata, consistent points
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0,8
0,9
1
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1
Computedspeed-upfactor
Measured speed-up factor
Err= 5,4%
R² = 0,79
Third case – City of Niigata Error R2
For all points 5.9% 0.75
For the consistent points 5.4% 0.79
8. 8
1.4.3 Discussion
Like in the previous cases, the points where the computed value of the speed-up factor is far
from the measured value are represented in the software UrbaWind.
Figure 7: Third case, quarter of Niigata, visualization
The situation is similar to the cases 1 and 2. Indeed, one can observe in the figure 7 that the
worst points correspond either to low-speed areas, or to areas where a small change of
location can lead to an important speed variation.
Moreover, the error and the determination coefficient allow again to validate the results of
UrbaWind. Indeed 90% of the points have an error value lower than 12% and the mean error
is lower than 5.9% for all points and 5.4% when selecting only the consistent points.
1.5 CONCLUSION
Finally, the table 1 shows that the results provided by UrbaWind are much closed to the
results of the experimental measurements of the Architectural Institute of Japan. Indeed the
typical error of the computations when considering all points is at most 8.5% and even
decrease to 5.5% in the first case.
Table 4: Summary table of the comparison Computations vs. Measurements
To conclude, this study allows validating the software UrbaWind as well for theoretical cases
(first and second cases) as for real cases (quarter of Niigata) by offering a minor error margin.
Error for all
points
Error for the
consistent points
R²
First case – Simple Block 5.5% 4.9% 0.93
Second case – Group of Blocks 8.5% 5.8% 0.71
Third case – City of Niigata 5.9% 5.4% 0.79
9. 9
Abbreviations:
iu : Components of the mean wind vector in a Cartesian frame
iu' : Components of the turbulent fluctuations
P : Mean pressure value
: Air dynamic viscosity
: Air density
Cd : Volume coefficient of frictions, which is proportional to the porous obstacle density
V : Volume of the considered cell.
References:
[1] Architectural Institute of Japan, 2008, Guidebook for Practical Applications of CFD to
Pedestrian Wind Environment around Buildings.
(http://www.aij.or.jp/jpn/publish/cfdguide/index_e.htm)
[2] Garratt J.R., 1992, The atmospheric boundary layer, Cambridge Atmospheric and space
sciences series.
[3] Ferry M., 2000, “The MIGAL solver”, Proc. Of the Phoenics Users Int. Conf.,
Luxembourg, 2000
[4] Ferry M., 2002, New features of the MIGAL solver, Proc. Of the Phoenics Users Int.
Conf., Moscow, Sept. 2002