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入口带倒圆结构的旋转长孔计算模型 被引量:1
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作者 李澎 吴宏 陶智 《航空动力学报》 EI CAS CSCD 北大核心 2012年第10期2205-2213,共9页
通过对旋转长孔的各种复杂工况开展CFD仿真,对现有经验关联式进行修正,并基于流体网络法对修正后的计算模型进行开发,开发完成的模型采用计算流体力学商业软件Simerics进行验证,结果表明:该模型考虑了入口倒圆结构对流动的影响,对于旋... 通过对旋转长孔的各种复杂工况开展CFD仿真,对现有经验关联式进行修正,并基于流体网络法对修正后的计算模型进行开发,开发完成的模型采用计算流体力学商业软件Simerics进行验证,结果表明:该模型考虑了入口倒圆结构对流动的影响,对于旋转长孔的模拟准确度较高,在低雷诺数及超声速等各种流动状态下均具有较广的适用性,并且只需基本的几何特征参数即可进行一维数值模拟,因此可以作为二次空气系统一维数值仿真的标准化模型使用. 展开更多
关键词 旋转长孔 入口倒圆 流量系数 经验关联式 二次空气系统
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Near-saturated soil hydraulic conductivity and pore characteristics as influenced by conventional and conservation tillage practices in North-West Himalayan region,India
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作者 Deepak Singh Alok Kumar Mishra +2 位作者 Sridhar Patra Sankar Mariappan Nisha Singh 《International Soil and Water Conservation Research》 SCIE CSCD 2021年第2期249-259,共11页
Tillage plays an important role in modifying soil hydraulic properties.The objective of the present study was to evaluate the effect of conservation tillage practices in a maize-wheat cropping system on nearsaturated ... Tillage plays an important role in modifying soil hydraulic properties.The objective of the present study was to evaluate the effect of conservation tillage practices in a maize-wheat cropping system on nearsaturated soil hydraulic properties and pore characteristics in the North-West Himalayan region,India.Three treatments viz.conventional tillage(CT),minimum tillage(MT),and zero tillage(ZT)were evaluated in terms of field saturated hydraulic conductivity(ks),unsaturated hydraulic conductivity k(h),the inverse of capillary length(a),flow-weighted mean pore radius(r0),numbers of pores per square meter(n0)and water-conducting macroporosity(Ɛ).The above hydraulic conductivity and pore characteristics were derived from steady-state water flux(q)measured using hood infiltrometer at 0,1,and3 cm pressure head for each treatment after seven years of establishment of this tillage experiment.Results revealed significantly(p<0.05)higher values of ks,k(h),a,andƐin ZT as compared with CT.MT had intermediate values.Higher a values suggested a greater gravity-dominated flow under ZT and MT as compared with CT.Analysis of r0 values indicated better connectivity of pores in ZT and MT as compared with CT.Macropore flow suggested that on average pore radii,>0.50 mm conducted about 63.60,68.01,and 75.97%of total flow(at 0 cm pressure head)in the corresponding water-conducting macroporosity of 0.00030,0.00044,and 0.00069%of soil volume under CT,MT,and ZT,respectively.Overall,zero-tillage based agriculture system was found to improve near-saturated soil hydraulic properties. 展开更多
关键词 Near-saturated hydraulic conductivity MACROPORES TILLAGE flow weighted mean pore radius Water-conducting macroporosity
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