City Research Online

Abstract

This research proposes the development of a novel concept of adaptable to wind façades for the protection and comfort of the building users at the top floors, and the pedestrians at the street level. Traditional studies are usually focused on wind effects of conventional façades, this PhD work addresses the critical gap in research by proposing adaptable façades. Existing literature on adaptable façades predominantly addresses issues related to the control of natural light, temperature, and ventilation, with minimal attention to wind-induced actions. This study is the first to propose the use of moving façade panels to enhance the comfort and safety of people both inside and outside buildings under wind actions.

The idea considers a façade that can adapt with the wind to limit the across wind vibrations and accelerations within the structure, as well as controlling the flow separation caused by the building footprint, to protect the users of the nearby streets. By reducing the oscillation of medium to high rise structures a more comfortable environment for their users would be achieved, while the structural and cladding elements would also be protected from the high wind-induced pressures. The concept of the smart façades are able to adapt to specific and localised wind conditions, with no requirement of energy supply in their operation. The idea is comprised by a double skin façade system with additional fins/screens that can rotate, adapting the surface of the structure to meet a more aerodynamic response. The screens are proposed to adapt to specific and localised wind conditions and the change of the façade configuration is proposed to be achieved by using the wind pressure as a driver force. Furthermore, it is suggested to also adapt the building in plan-view through the use of this façade novelty, targeting to a more streamlined flow around medium to high rise structures.

This report presents the work completed through this PhD project. The study is based on the development of a novel façade idea. Hence a large part of this report is associated with the identification of studies focused on smart façade developments globally as well as the industry current and future needs when considering a continuously urban growth.

There is growing interest in façades of buildings with moving screens that can adapt to different environmental conditions to optimise the energy usage and comfort. These façade elements can significantly affect the wind flow around the building, both at the local and the global levels. This research presents a programme of computational fluid dynamic (CFD) analysis to study the influence of the shape of the building on the wind flow when different façade configurations are considered. In order to assess this influence, two-dimensional (2D) and a three-dimensional (3D) CFD analyses were employed. The analysis started considering a perfect square as a benchmark shape. This shape was altered by adding setbacks or wedges at the corners of the building to observe significant differences in the average and time-histories of the aerodynamic coefficients. The effect of these façade elements on the wind flow at the pedestrian level was examined through 3D CFD analysis. The comfort of pedestrians was assessed against the Wind Microclimate Guidelines for City of London.

Wind tunnel tests were conducted in order to validate the CFD outcome and also to examine the aerodynamic performance of the proposed novelty. Furthermore, a Fluid Structure Interaction (FSI) analysis was conducted using an ABAQUS model in conjunction with the MDyn Python library. This approach was used to assess the impact of the proposed façade concept on the occupant comfort. The relevant FSI results were compared against existing standards and codes of practice. From this PhD study, it is indicated that the adaptable façades can offer significant enhancement on both occupant and pedestrian comfort under wind actions.

Publication Type:	Thesis (Doctoral)
Subjects:	T Technology > T Technology (General) T Technology > TA Engineering (General). Civil engineering (General) T Technology > TH Building construction
Departments:	School of Science & Technology > Department of Engineering School of Science & Technology > School of Science & Technology Doctoral Theses Doctoral Theses

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