Computational Fluid Mechanics - Literature review Example

COMPUTATIONAL FLUID MECHANICS Literature Review/Position Paper Table of Contents Executive summary 3 Introduction 3 Related technical and scientific advance 5 CFD and climate change 7 CFD and energy 8 CFD and Health 8 CFD and security 9 Appraisal 9 Conclusions 10 Bibliography 11 Executive summary Urban physics is a core area being applied in every dimensions of the society, from studying climate change to accessing security and aging. Consequently, it is important to study the aspects the that contribute to the importance of urban physics. Computational fluid mechanics (CFD) is a numerical simulation method used as assessment tool in urban physics, besides various reduced-scale laboratory measurements. In which case, the study of CFD implies the review of engineering of physical processes found in industrial areas in the urban zones. The adoption of computational fluid mechanics has seen it exhibit various fruitful transition, from a mere field to an increasingly developed field in practice and design. This literature review, in form of a position paper, provides a theoretical background of the CFD plus supporting views about its mechanism and its usage within our organization. This will involve studying aspects of technical challenges associated with using the tool within the organization. Further, possibilities and limitations are also presented to further the exploration of how CFD applies to urban physics. Intuitively, this will provide a benchmark for measuring the spatial and temporal scales that can be associated with the position of computational fluid mechanics. Finally, it would be important to scale the position of the review by focusing on the technical aspects of using CFD in the organization. For this reason it would be possible to extensively discover the future of CFD in urban physics. Introduction In mostly urban areas, especially in the industries, urban physics is a core field in facilitating various physical processes. Essentially the field deals with the transmission of heat and mass experienced in the outdoor and indoor for the urban environment. Further, it focuses this concept of heat and mass transmission to its interaction with human and materials used in production. Conclusively, an organization is likely to apply this field ensuring a healthy and sustainable outdoor and indoor environment through encompassing all the associated constraints such as security, energetic and health, all which are considered as grand societal challenges. For this particular reasons, urban physics with all its components is adopted widely across engineering disciplines, scaling from mechanical to electrical engineering. One of the major component that makes urban physics formidable is Computational Fluid Dynamics mainly used in numerical simulation within the particular organization. This technique of numerical simulation, for CFD, makes possible the successful operation of other components of urban physics: field measurement and full-scale or reduced-scale wind-tunnel measurements (Tan et al, 2015, 76). CFD, as numerical simulation tools acts as an effective alternative in the organization given that it can avoid limitations associated with the other tools. This challenges include multitphase flow problems and buoyant flow problems, specifically experienced by both field measurement and wind-tunnel measurement. It can provide thorough data on the pertinent flow variables in the whole calculation domain (“whole-flow field data”), under contained conditions and without similarity limitations (Emmanuel & Kruegler, 2010, 112). However, the accuracy of CFD comes into play as an important aspects which must be put in control. Especially, this must include taking into control geometrical implementation associated with the model and understanding of the results in the event of choosing the proper solution strategies. The selection process including making choices between various options; the steady Reynolds-averaged Navier-Stokes (RANS) approach, the unsteady RANS (URANS) approach, Large Eddy Simulation (LES) or hybrid URANS/LES (Sarrat et al, 2006, 1750). Further, errors arising from numerical and modeling must be taken into consideration through verification and validation to contain them within the system. Further, the validation process might also require the use of high-quality data as compared to other simulation models. The literature review, in form of a position paper, provides a theoretical background of the CFD plus supporting views about its mechanism and its usage within our organization. This will involve studying aspects of technical challenges associated with using the tool within the organization. Further, possibilities and limitations are also presented to further the exploration of how CFD applies to urban physics. Intuitively, this will provide a benchmark for measuring the spatial and temporal scales that can be associated with the position of computational fluid mechanics. Finally, it would be important to scale the position of the review by focusing on the technical aspects of using CFD in the organization. For this reason it would be possible to extensively discover the future of CFD in urban physics. Related technical and scientific advance As a tool used in urban physics, CFD has been seen to makes various steps in the society because of it adoption in various field. In which case, the grand societal challenges as aforementioned make it possible to study the advances made by CFD, especially for the associated organizations. This is achieved through various approaches: RANS, URANS,hybrid URANS/LES and LES simulations. The following figure shows the connection of CFD to various societal challenges. Figure 1: Adoption of CFD in various institutions The above chart shows the connection between CFD and various societal challenges, thereby depicting both technical and scientific advances made by the tool in the society. This advances enforce the adoption of the tool in various field especially in case of an organization focusing in those field. The various advances related to solving the above challenges include; CFD simulation of micro-scale pollutant dispersion in the built environment, ventilative cooling and vehicle aerodynamics on the basis of their energy consumption, warning systems for toxic accidents and terrorist attacks, air pollution traffic, control of show drift, avoidance of wind danger and provision of healthy and comfortable environment (Memon et al, 2010, 440). The following is a categorical discussion of the field advances made by CFD. CFD and climate change As a grand societal challenge, climate change has given much focus to CFD to help in moderating the impacts on the society. In which case, CFD makes it possible through allowing research on both outdoor and indoor thermal environment. Adverse effects of climate change that are particularly relevant for urban areas are sea-level rise and coastal flooding, more intense and frequent heat waves, more intense and frequent precipitation events, pluvial flooding, drought and increased air pollution (Watkiss, 2011, 46). The combination of urbanization and climate change is particularly problematic. Particularly, urbanization increases the influence of climate change effects on the population through such occurrence of heat waves, flooding and precipitation changes. This occurrence has been facilitated by the increased growth of cities and budding of other new cities. Consequently, the society finds it difficult to deal with this problem since it directly contributes to the livelihood of the society. CFD comes out as one of the most effective answers for this problems, especially in facilitating moderation of the above aspects. CFD has been used as a facilitator in moderating the impact of climate change. This is in form of studying heat waves that are required to change weather extremities and therefore lead to variability in a given area. Through the use of potential flow solver, CFD contributes to studying the specific heat capacity of a particular areas. This helps in designing strategies for dealing with any evidenced change in heat characteristics of a particular area. City inhabitants are especially vulnerable to the consequences of climate change, such as heat waves, increased air pollution and rising sea levels (Changnon et al, 1996, 1123). Further, CFD is used in the study of increase in meteorological phenomena, wind loads on vehicles and problems related to penetration of rain. In which case, the computational tool helps in studying the extent of these aspects, which then can help in formulating proper strategies for adaptation during such occurrences. CFD and energy Major aspects of energy consumption in the society make the adoption of CFD feasible. Considering that energy is an important product in the society, both in the production process and in complementing livelihood, the advancement of CFD is worth exploring. CFD advancement in energy include study of vehicle dynamics through facilitating exploration of energy consumption therein. This involves simulating a vehicle engine and studying the amount of fuel consumption. In addition, through facilitating a built environment, the simulation model helps in carrying out research on solar energy and wind energy. Consequently, this made computational dynamics an important aspect in the society that can help in solving various problems exhibited by the society, especially in terms of energy consumption (Garssen et al, 2005, 259). CFD and Health CFD has also made a worth noting advancement in the field of health. The advancement is of worth significance for this position paper because health is a grand society issue considered as a major pillar in both social and economic dimensions. In which case, CFD facilitates health practices by providing a framework for carrying research on thermal environment and heat stress. It measures the extent of thermal environment and heat stress thereby helping in establishing limits within which human being and their animals can survive in. Further, through the concepts of CFD it is easy to study air quality in urban centers, with its action complimented by its ability to study dispersion of pollutants (Awbi, 2003, 56). Consequently, the involved administrators are able to put up effective protective measures for reducing the impacts of the related process. Another important advancement is the ability of CFD to measure avoidance of wind-danger for those pendestrians living in the high-rise buildings. Other aspects include measurement of natural ventilation to avoid indoor pollutants. CFD and security In this case, security can be contextualized in terms of pollution and attacks from terrorists. Consequently, CFD comes out as an important model that is adopted to develop warning systems both for an event of toxic accident or in extreme cases attack by terrorists. Further, in a case of destructive meteorological phenomena such as windborne debris, CFD helps in avoiding the associated impacts because it can be used for providing the warning. The simulation model can also be adopted in determining the occurrence and spreading of fire thereby complimenting on fires safety. Appraisal In order to effectively appraise this research technique, it is important to consider the success of the approaches used therein. These approaches include RANS, URANS,hybrid URANS/LES and LES simulations. Although steady RANS is linked with quite important confines in terms of modeling significant features of the fully turbulent stream around outspoken frames in urban physics, still, it is by far the most widely used approach in most urban physics focus areas. The reason for this is twofold: (i) the computational expense of LES and (ii) the increased model complexity of LES in combination with the absence of extensive best practice guidelines for LES (Mochida & Lun, 2008, 1500). Such Best practice strategies exist for RANS, as they have been advanced in the previous 15 years. From this particular reasoning, carrying out a risk assessment yields a notion worth supporting the low-risk vs high returns associated with the use of the technique. The approach of RANS is well established in CFD, and complements its functioning as successful in meeting needs of the particular organization. Conclusions Computational fluid mechanics (CFD) is a numerical simulation method used as assessment tool in urban physics, besides various reduced-scale laboratory measurements. In which case, the study of CFD implies the review of engineering of physical processes found in industrial areas in the urban zones. The paper has successfully confirmed the fact that Computational Fluid Dynamics, for urban physics has undergone a prosperous transition to be an established field in the both practice and design. In order to achieve this the paper illuminated on the technical and scientific advances that have been made possible by adoption of CFD. In which case, it is found that CFD has a wider application especially in grand societal challenges such as climate change, energy issues, health issues and security issues. The relationship between CFD and these societal issues, have also been illustrated by chart. Further, in appraisal the research established that RANS is by far the most widely used approach in most urban physics focus areas. RANS is an approach well established in CFD; consequently, it can be said that it associates with low-risk for the organization. Best practice strategies exist for RANS, as they have been advanced in the previous 15 years. Bibliography Watkiss P. Final Report. The ClimateCOST project, vol. 1. Europe: Stock Environ Inst; 2011. Xu P, Huang YJ, Miller N, Schlegel N, Shen P. Impacts of climate change on building heating and cooling energy patterns in California. Energy 2012;44:792-804. Changnon SA, Kunkel EK, Reinke BC. Impacts and responses to the1995 heat wave: a call to action. Bull Am Meteorol Soc 1996;77:1497-506. Garssen J, Harmsen C, de Beer J. Effect of the summer 2003 heatwave on mortality in the Netherlands. Eurosurveillance 2005;10:165-7. Mochida A, Lun IYF. Prediction of wind environment and thermal comfort at pedestrian level in urban area. J Wind Eng Ind Aerodyn, 2008;96 (10-11):1498-1527. Awbi HB. Ventilation of buildings. London, UK: Spon Press; 2003. Sarrat C, Lemonsu, Masson V, Guedalia D. Impact of urban heat island on regional atmospheric pollution. Atmos Environ 2006;40:1743-58. Tan J, Zheng Y, Tang X, Guo C, Li L, Song G, et al. The urban heat island and its impact on heat waves and human health in Shanghai. Int J Biometeorol 2010;54:75-84. Memon RA, Leung DYC, Liu C-H, Leung MKH. Urban heat island and its effect on the cooling and heating demands in urban and suburban areas of Hong Kong. TheorAppl Climatol 2010;103:441-50. Emmanuel R, Krüger EL. Urban heat island and its impact on climate change resilience in a shrinking city: the case of Glasgow, UK. Build Environ 2012;53:137-49. Read More