Ornament and function

The architects and builders in the past lacked our knowledge concerning fluid dynamics, but they exhibited a deep rooted ability to observe and reflect ‐ thus, different cultures have developed by trial and error. The authors have produced a stimulating analysis which couples the science of fluid dynamics and a sensitive understanding of past cultures. The paper is recommended reading.     

本科流体力学课程中引入CFD内容的探索与实践

流体力学是大部分工科学生的专业基础必修课,计算流体力学软件是流体力学科学与工程研究的重要工具。首先,论证流体力学教学中适当引入计算流体力学的必要性;其次,从理论基础、教学条件、学时安排、教学内容、学时分配和考核办法等方面论证了在流体力学教学中适当引入计算流体力学的可行性;最后,为了激发学生的学习积极性和主动性,提升教学质量,尝试性地在教学中引入了计算流体力学。结果表明,引入计算流体力学后能激发学生对流体力学的兴趣,提高学生的学习能力,培养学生的创新性思维,拓宽学生的知识面,加深学生对基本理论的理解,从而提高教学质量,学生期末成绩明显提高。文章提出的流体力学课程改革新思路,为今后引入计算流体力学教学提供了必要的准备和参考。     

Modelling the Performance of Combined-Sewer Overflow Chambers

This paper reviews some of the physical model studies which have been carried out in the UK to determine the performance of combined-sewer overflow chambers. The topic of computational fluid dynamics is introduced and identified as a viable alternative to physical modelling. The limitations of both modelling approaches are discussed. It is concluded that the future of chamber modelling will be a combination of computational fluid dynamics and physical techniques.     

Natural ventilation design for houses in Thailand

This paper explores the potential of using natural ventilation as a passive cooling system for new house designs in Thailand. The characteristics of past and present Thai houses are analyzed in terms of climate, culture, and technology. Based on the thermal comfort requirements for the Thai people and the climate conditions in Bangkok, the study found that it is possible to use natural ventilation to create a thermally comfortable indoor environment in houses in a Bangkok suburb during 20% of the year. This study also develops comprehensive design guidelines for natural ventilation at both the site planning and individual house levels by using computational fluid dynamics.     

Airborne spread of expiratory droplet nuclei between the occupants of indoor environments: A review

This article reviews past studies of airborne transmission between occupants in indoor environments, focusing on the spread of expiratory droplet nuclei from mouth/nose to mouth/nose for non‐specific diseases. Special attention is paid to summarizing what is known about the influential factors, the inappropriate simplifications of the thermofluid boundary conditions of thermal manikins, the challenges facing the available experimental techniques, and the limitations of available evaluation methods. Secondary issues are highlighted, and some new ways to improve our understanding of airborne transmission indoors are provided. The characteristics of airborne spread of expiratory droplet nuclei between occupants, which are influenced correlatively by both environmental and personal factors, were widely revealed under steady‐state conditions. Owing to the different boundary conditions used, some inconsistent findings on specific influential factors have been published. The available instrumentation was too slow to provide accurate concentration profiles for time‐dependent evaluations of events with obvious time characteristics, while computational fluid dynamics (CFD) studies were mainly performed in the framework of inherently steady Reynolds‐averaged Navier‐Stokes modeling. Future research needs in 3 areas are identified: the importance of the direction of indoor airflow patterns, the dynamics of airborne transmission, and the application of CFD simulations.     

CFD在臭氧接触系统优化中的应用

利用计算流体力学（CFD）技术,通过计算流体的停留时间分布,模拟了深圳某水厂臭氧接触池的水力效率,对臭氧接触系统进行了优化.结果表明,未设置导流板的接触池水力效率较低,T10/HRT仅为0.40.通过设计优化,增加了导流板,可将接触池的水力效率提高73%,T10/HRT为0.66.     

A review of methods,applications and limitations for incorporating fluid flow in the discrete element method

The past decade has witnessed the substantial growth in research interests and progress on the subject of coupled hydro-mechanical processes in rocks and soils, driven mainly by the surge of research in unconventional hydrocarbon reservoirs and associated hazards. Many coupling techniques have been developed to include the effects of fluid flow in the discrete element method (DEM), and the techniques have been applied to a variety of geomechanical problems. Although these coupling methods have been successfully applied in various engineering fields, no single fluid/DEM coupling method is universal due to the complexity of engineering problems and the limitations of the numerical methods. For researchers and engineers, the key to solve a specific problem is to select the most appropriate fluid/DEM coupling method among these modeling technologies. The purpose of this paper is to give a comprehensive review of fluid flow/DEM coupling methods and relevant research. Given their importance, the availability or unavailability of best practice guidelines is outlined. The theoretical background and current status of DEM are introduced first, and the principles, applications, and advantages and disadvantages of different fluid flow/DEM coupling methods are discussed. Finally, a summary with speculation on future development trends is given.     

Using computational fluid dynamics to improve the drag coefficient estimates for tall buildings under wind loading

Wind is the main horizontal force acting on tall buildings. This force is proportional to the drag coefficient. The drag coefficient is an important factor in their structural design. Designers have historically relied upon experimental wind tunnel results to estimate the drag coefficient. However, this process is both expensive and time consuming. In this study, we alternatively computed the drag coefficient (apart from the pressure, force, and bending moment) using computational fluid dynamics for a typical 93‐m‐high residential building. The simulation considers the actual building geometry, as well as the neighborhood roughness effects. We compared these results with the conventional estimates contained in the Brazilian code NBR‐6123/1988 and Eurocode EC1. The results indicated that the pressures obtained herein near the top of the building were lower compared to those obtained using conventional estimation methods given in codes. Comparatively, the obtained bending moment relative to the base of the building was higher, indicating the existence of significant drag forces not considered in codes. In fluid dynamics simulations, the drag coefficient is determined for each terrain condition. Computational fluid dynamics can effectively simulate the drag force and resultant forces in the direction of the flow, as well as the vortices that result during coating detachment and other types of damage.     

Outdoor algal mass cultures—I. Applications

Algal mass culturing research has been carried out in many parts of the world for past 30 yr. Whereas early efforts were directed towards single-celled protein production for human consumption, many new applications have evolved including wastewater treatment, water renovation, nutrient recycling, production of chemicals, aquaculture and bioconversion of solar energy. Photosynthetic yields over 30g dry wt m^?2day^?1 have been attained on occasion in many locations for short periods and yields between 15 and 25 g dry wt m^?2 day^?1 for longer periods are now common. It appears that bioconversion of solar energy with algal cultures is not attractive because of the tremendous quantities of land, water and nutrients required. Similarly, single-celled protein from microalgae is beset with numerous problems associated with nutritional quality, toxicology and economics. The main attractiveness of algal mass cultures is that they have great versatility to be integrated into multi-use systems for simultaneously solving several environmental problems. Their use probably will be limited to small specific applications and not on the massive scale projected in the past.     

Reduced-scale building model and numerical investigations to buoyancy-driven natural ventilation

Similarities of a reduced-scale building model using air as the working fluid for buoyancy-driven natural ventilation have been analyzed and experiments were carried out using the scaled model for a common natural ventilation building, which has open office floor plans connected to a central atrium. Both open and closed cases have been investigated for the stack vents, located at the top of the atrium. Inputs for the scaled building model were taken from results measured in the prototype building by the authors. The parameters of the scaled building model's experiments thus were used as inputs into a computational fluid dynamics (CFD) simulation model to compare predicted and measured airflow patterns, temperatures and velocity distributions in the scaled building model.     

Application of computational fluid dynamics in building performance simulation for the outdoor environment: an overview

This article provides an overview of the application of computational fluid dynamics (CFD) in building performance simulation for the outdoor environment, focused on four topics: (1) pedestrian wind environment around buildings, (2) wind-driven rain on building facades, (3) convective heat transfer coefficients at exterior building surfaces and (4) air pollutant dispersion around buildings. For each topic, its background, the need for CFD, an overview of some past CFD studies, a discussion about accuracy and some perspectives for practical application are provided. This article indicates that for all four topics, CFD offers considerable advantages compared with wind tunnel modelling or (semi-)empirical formulae because it can provide detailed whole-flow field data under fully controlled conditions and without similarity constraints. The main limitations are the deficiencies of steady Reynolds-averaged Navier–Stokes modelling, the increased complexity and computational expense of large eddy simulation and the requirement of systematic and time-consuming CFD solution verification and validation studies.     

地铁列车区间隧道着火时行车安全性的讨论

当地铁列车在区间隧道内发生火灾时,现行的关于地铁列车区间隧道着火时的应急对策是:如果列车的条件允许,尽量驶到下一个车站,利用前方车站疏散乘客.本研究运用计算流体力学(CFD)的方法,对运行中地铁列车周围不同部位的相对风速及其速度场分布特性进行了模拟分析;重点讨论了当地铁列车区间隧道着火时,考虑到风助火势的影响,行进中地铁列车的行驶速度对火势蔓延的影响;进而对地铁列车区间隧道着火时的安全行驶速度进行了初步的探讨.     

大气式燃气燃烧器引射器的CFD研究

利用计算流体力学(CFD)，对燃气大气式燃烧器引射器的流场进行模拟研究，形成燃气的速度场压力场、浓度场等流体状态参数，达到设计引射器的目的。     

建筑户型对自然通风效果的影响

从自然通风的基本原理入手,采用计算流体力学方法对典型户型的自然通风效果进行了研究,模拟发现不同户型对自然通风的效果影响很大,提出了改进自然通风效果的建议,对今后的建筑设计给出了很好的参考和改进依据。     

设置非线性粘滞阻尼器结构地震响应的时程分析

本文基于国内外现有的粘滞阻尼器性能试验和计算研究,提出单自由度非线性粘滞阻尼器的计算方法。文中给出了粘滞阻尼器非线性运动方程的解法,并运用该方法进行了大量的比较计算,研究了单自由度非线性粘滞阻尼器的动力响应特性。     

Performance of coupled building energy and CFD simulations

The integration of building energy simulation (ES) and computational fluid dynamics (CFD) programs can provide more accurate prediction of building energy use and indoor environment due to the complementary information provided by the two programs. This paper outlines briefly a coupled energy simulation and computational fluid dynamics program with different coupling methods and validates the coupled program by using four sets of experimental data from literature. The comparison of the simulated results with the experimental/empirical data reveals the advantages of the integrated building simulation over the separated energy simulation and computational-fluid-dynamics applications. The program was then used to calculate the cooling load of a large-scale indoor auto-racing complex.     

单面开孔空间结构风压分布及风致内压研究

本文利用计算流体动力学通用软件FLUENT对具有复杂体型的大跨空间屋盖结构进行数值分析,研究了结构在体型逐渐变化的过程中风压分布的变化规律;针对单面开孔结构的风致内压问题,以及内压对结构的影响做了深入的研究,得到一些有价值的结论.     

乡土文化,现代演绎--关于重庆翡翠湖一期项目

居住文化——从市场开放到现在已经20多年了,最初往往去西方寻找答案。但建筑师接触过世界各地的不同的文化、不同的地方之后,才觉得中国人集聚了几千年的居住文化是最成熟和充满浪漫的。所以在重庆翡翠湖别墅项目里,建筑师利用了一些老中国的元素来处理一些现代中国的居住问题。     

Coupled dynamics of tensioned buoyant platforms and mooring tethers

A mathematical model is presented of the coupled dynamics of a tensioned buoyant surface platform and the lateral dynamics of its taut mooring tethers. A finite element model of the lateral mooring tether dynamics is extended to take account of nonlinear square law fluid damping by a simple global ‘whole tether’ linearization and an alternative computationally more expensive ‘element-by-element’ linearization scheme. The resultant finite element model is combined with the surface platform dynamic analysis and the coupled dynamic model is used to investigate the effects of water depth, surface platform mass and tether mass per unit length on the tether displacements and bending stresses as well as the resultant surface platform displacements. The results show that the bending stresses induced in the tethers due to their dynamic motions are quite small and that the tether dynamics only affect the motion response of the platform appreciably if the tethers are long (1500 m or more), have a large mass per unit length and have a relatively low tension; or if the platform mass is relatively small. It was also found that the additional computing time required for the local ‘element-by-element’ equivalent linearization was not matched by the small improvement in accuracy obtained over the global ‘whole tether’ technique.     

Business and Planning: A Strategic-Relational Approach

Business interests and agendas have been amongst the most influential drivers in the restructuring of the UK planning system over the past 30 years. Yet questions regarding the nature of business and business agendas and the power and influence of business interests have been somewhat under-developed in recent planning theory. In this paper we adopt a distinctive approach to theorizing business interest representation and business–state relations based on a strategic-relational approach. This seeks to establish an explicit focus on the dynamics of business–state relations, a standpoint of particular salience to planning and planning theory. It also offers distinctive theoretical perspectives regarding questions of business power and the evaluation of business influence, as well as informing contemporary debates around the engagement of business in planning processes. These insights hold significant potential in extending understanding of governance dynamics and the realities of planning politics and practice.