Impacts of uneven surface heating of an ideal street canyon on airflows and indoor ventilation: Numerical study using OpenFOAM coupled with EnergyPlus
In this study, the impacts of uneven and time-varying heating of surfaces inside an ideal urban street canyon (aspect ratio = 1) on single-sided indoor natural ventilation are analyzed. This work introduces a methodology for a numerical approach based on the coupling between a computational fluid dynamics (CFD) model and an energy balance model. First, EnergyPlus is employed to calculate the time-varying and uneven surface heating. Simulations are performed at four typical study times (05:00, 09:00, 15:00, 20:00) during a hot summer day (July 15) in Wuhan, China. Second, the surface temperature results are transferred to OpenFOAM for CFD simulation. Two inlet wind velocities (Uref) are investigated. The results show that for a relatively strong ambient wind (Uref = 3 m/s), the buoyancy caused by surface heating does not significantly change the airflow structures and indoor ventilation compared with those in the isothermal case. However, for a weak ambient wind (Uref = 0.5 m/s), the airflow structures inside the street canyon vary with the time of day. Moreover, the average air exchange rate (ACH) differs by −25.0% to 15.9% compared with that in the isothermal case, and the ACH of a single room increases by up to 2710%. The results indicate that the surface-heating-induced buoyancy is nonnegligible and should be carefully investigated, especially for weak ambient winds.
This report describes how the authors adapted the research methodologies to continue work throughout the pandemic, despite various restrictions. The original studies had very high participation rates because of several methodological approaches that minimized barriers, especially in-person data collection. During the pandemic, distancing requirements precluded replication of these same methods. Research strategies that enabled staff participation during working hours, with designated time allotted for participation, was key for ensuring high participation rates, as access to technology, availability of free time and oth...
New York has announced three more cases of the omicron variant of the coronavirus, bringing to eight the number of state cases linked to the new variant
If we keep allowing this virus to spread through unvaccinated populations, the next variant could be even more deadlyCoronavirus – latest updatesSee all our coronavirus coverageIt ’s almost two years since we first heard of Covid-19, and a year since the first Covid vaccines were rolled out. Yet this staggering progress is being squandered. We have drifted for months now, with richer countries, taking a very blinkered domestic focus, lulled into thinking that the worst of t he pandemic was behind us. This variant reminds us all that we remain closer to the start of the pandemic than the end.There is a lot we ne...
Sir Jeremy Farrar, director of Wellcome Trust, suggests emergence of Omicron variant means pandemic is far from overCoronavirus – latest updatesSee all our coronavirus coverageThe emergence of the Omicron variant shows that the world is “closer to the start of the pandemic than the end”, one of Britain’s most senior scientific figures has warned, as he lamented a lack of political leadership over Covid.Sir Jeremy Farrar, the director of the Wellcome Trust whostepped down as a government scientific adviser last month, said the progress in combatting Covid-19 since its emergence was “being squan...
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Christmas parties Johnson’s staff held last year broke coronavirus restrictions.
The omicron coronavirus variant has been found in 12 U.S. states just three days days after the first case in the country was announced.
[Thomson Reuters Foundation] Developing countries want the right to make their own COVID-19 vaccines, but opponents say there are better ways to boost supplies
South Africa's Covid-19 cases have nearly quadrupled in the last four days, underscoring concerns around how contagious the new coronavirus Omicron variant might be as the country enters its... #southafrica #southafricacovid #omicron