提出二维湍流热对流DNS模拟的并行直接求解方法(Parallel Direct Method of DNS,PDMDNS),在"天河二号"超级计算机上实现高Ra和极高Ra湍流热对流大规模DNS计算。高分辨率的湍流热对流计算结果表明不同Ra(10~8≤Ra≤10^(13))的...
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提出二维湍流热对流DNS模拟的并行直接求解方法(Parallel Direct Method of DNS,PDMDNS),在"天河二号"超级计算机上实现高Ra和极高Ra湍流热对流大规模DNS计算。高分辨率的湍流热对流计算结果表明不同Ra(10~8≤Ra≤10^(13))的瞬时温度场的流场特性完全不同。较低Ra流场中有明显的大尺度环流和角涡;较高Ra流场中羽流运动充满随机性;更高Ra流场出现小尺寸漩涡并不断从上下底板产生,这些涡相互影响作用,随大尺度环流一起作绕行运动。二维湍流热对流的Nu与Ra存在标度关系,标度律约为0.3。
Human water regulation (HWR), groundwater lateral flow (GLF) and the movement of frost and thaw fronts (FTFs) affect soil water and thermal processes, as well as energy and water exchanges between the land surface and...
Human water regulation (HWR), groundwater lateral flow (GLF) and the movement of frost and thaw fronts (FTFs) affect soil water and thermal processes, as well as energy and water exchanges between the land surface and atmosphere. Reasonable representation of these processes in land surface models is very important to improving the understanding of land-atmosphere interactions. In this study, mathematical descriptions of GLF, HWR and FTFs were synchronously incorporated into a high-resolution community land model named the Land Surface Model for Chinese Academy of Sciences (CAS-LSM). With a series of atmospheric forcings and high-resolution land surface data from the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) program, numerical simulations of the period 1981–2013 using CAS-LSM with 1-km resolution were conducted for an endorheic basin,the Heihe River Basin in China. Compared with observations, CAS-LSM reproduced the distributions of groundwater, evapotranspiration and permafrost reasonably, and well matched the temporal changes in ground temperature, heat fluxes and *** illuminate the temporal and spatial characteristics of frozen soil and the changes in the land-atmosphere exchange of carbon, water and energy. The permafrost and seasonally frozen soil were distinguished. In the seasonally frozen areas,the maximum soil frost depth increased by 0.65 mm/year within natural areas and decreased by 2.12 mm/year in human-dominated areas. The active layer thickness increased 8.63 mm/year for permafrost. In the permafrost zone evapotranspiration and latent heat flux increased, and the sensible heat flux declined. In the humandominated areas water use raised the latent heat flux and reduced the sensible heat flux, net ecosystem exchange and streamflow recharging to the eco-fragile region in the lower reaches. Results suggested that the land surface model CAS-LSM is a potential tool for studying land surface processes, especially in cold and arid
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