Determination of Wind Pressure Coefficients for Arc-Shaped Canopy Roof with Numerical Wind Tunnel Method

In this paper,the wind load on an arc-shaped canopy roof was studied with numerical wind tunnel method(NWTM) .Three-dimensional models were set up for the canopy roof with opened or closed skylights.The air flow around the roof under wind action from three directions was analysed respectively.Wind pressure coefficients on the canopy roof were determined by NWTM.The results of NWTM agreed well with those of wind tunnel test for the roof with opened skylights,which verified the applicability and rationality of NWTM.The effect of the closure of skylights was then investigated with NWTM.It was concluded that the closure of the skylights may increase the wind suction on the top surface of the roof greatly and should be considered in the structure design of the canopy roof.

A cloud-based platform to predict wind pressure coefficients on buildings

Natural ventilation(NV)is a key passive strategy to design energy-efficient buildings and improve indoor air quality.Therefore,accurate modeling of the NV effects is a basic requirement to include this technique during the building design process.However,there is an important lack of wind pressure coefficients(CP)data,essential input parameters for NV models.Besides this,there are no simple but still reliable tools to predict CP data on buildings with arbitrary shapes and surrounding conditions,which means a significant limitation to NV modeling in real applications.For this reason,the present contribution proposes a novel cloud-based platform to predict wind pressure coefficients on buildings.The platform comprises a set of tools for performing fully unattended computational fluid dynamics(CFD)simulations of the atmospheric boundary layer and getting reliable CP data for actual scenarios.CFD-expert decisions throughout the entire workflow are implemented to automatize the generation of the computational domain,the meshing procedure the solution stage,and the post-processing of the results.To evaluate the performance of the platform,an exhaustive validation against wind tunnel experimental data is carried out for a wide range of case studies.These include buildings with openings,balconies,irregular floor-plans,and surrounding urban environments.The C_(P) results are in close agreement with experimental data,reducing 60%-77% the prediction error on the openings regarding the EnergyPlus software.The platform introduced shows being a reliable and practical C_(P) data source for NV modeling in real building design scenarios.

Structural Analysis of Timber Gridshell Covered by OSB Panels Considering the Effect of Wind

Timber gridshells have been increasingly gaining attention for combining structural efficiency with an attractive architectural design.The use of timber in this structural system gives freedom to the architectural configuration and implies light and efficient construction.This study presents a methodology for the structural analysis of a gridshell covered by OSB(oriented strand board)panels,taken as a case study,and evaluates the model using finite element analysis.The gridshell’s final geometry was obtained from simulations of the effect of permanent load on the mesh.The structural evaluation was numerically estimated via ANSYS software’s CFX platform,considering the effect of wind on the fluid-structure interaction,as well as the results of a static analysis of the structure,including ultimate and serviceability limit state verifications.To assess the influence of the OSB panels on the gridshell’s behavior,two values of elastic modulus are considered.The analysis of a timber gridshell,which covers a span of 14 m by 28 m,demonstrated that this lightweight structure can be considered rigid,and the increase in stiffness of the OSB panels,used as the structure’s coating,can represent an expressive strength and stiffness gain for this type of gridshell.

Wind pressure acting on greenhouses: A review

Greenhouses are widely used in agricultural and horticultural production.With the characteristics of lightweight,small stiffness and high flexibility,greenhouses are sensitive to wind loads.In the calculation of wind loads,the wind pressure coefficient(Cp)is essential.The rationality of the value directly affects the safety and economy of greenhouses.Therefore,the Cp values estimation is one of the most important issues in the design of greenhouses.In order to make full use of the existing research results,in this study,three main methods for estimating Cp values were analyzed,namely,full-scale field experiment,wind tunnel experiment and numerical simulation.Five factors influencing the Cp values were then reviewed including greenhouse design parameters,greenhouse group,overhanging eaves,ventilation and wind direction.Based on the existing researches,suggestions for future development and research work were also put forward.Owing to the flexibility and deformability of greenhouses,the fluid-solid coupling method should be used to analyze the effects of vibrations on wind pressures.The interaction of building parameters(such as the number of spans,ridge height,roof shape and slope angle)and terrain around the greenhouse should be taken into consideration comprehensively.The destructive vortices occurred on the greenhouse should be further investigated.