This paper investigates the problem of oblique hydro magnetic stagnation point flow of an electrically conducting Casson fluid over stretching sheet embedded in a doubly stratified medium in the presence of thermal ra...This paper investigates the problem of oblique hydro magnetic stagnation point flow of an electrically conducting Casson fluid over stretching sheet embedded in a doubly stratified medium in the presence of thermal radiation and heat source/absorption with first order chemical reaction.It is assumed that the fluid impinges on the wall obliquely.Similarity variables were used to convert the partial differential equations to ordinary differential equations.The transformed ordinary differential equations are solved numerically using Runge-Kutta-Fehlberg method with shooting technique.It is observed that a boundary layer is formed when the stretching velocity of the surface is less than the in viscid free stream velocity at a point decreases with increase in the non-Newtonian rheology parameter.The augmentation of the temperature is observed with the magnetic parameter,heat source parameter and thermal radiation parameter while a reverse effect with thermal stratification number,Prandtl number and the velocity ratio parameter.Influence of Skin friction coefficient,Nusselt number and Sherwood number on the flow configurations for different values of pertinent parameters are portrayed graphically and discussed.Numerical results are compared with the published results and are found to be in good agreement with previously published results as special cases of present problem.The mass concentration is seen to be decrease with Schmidt number,chemical reaction parameter and solutal stratification number.展开更多
Based on the two-stream approximation a broad-band parameterization scheme for solar radiative flux calculation is presented.The whole solar spectral region from 0.2 to 3.58 μm is divided into three broad spectral in...Based on the two-stream approximation a broad-band parameterization scheme for solar radiative flux calculation is presented.The whole solar spectral region from 0.2 to 3.58 μm is divided into three broad spectral intervals.The effec- tive broad-band optical depths and single scattering albedos in the atmosphere in each spectral interval can be obtained using parameterized formulae from known atmospheric parameters.The overlapping scattering and/or absorption ef- fects of two atmospheric constituents are considered properly.In the consideration of radiative effect of clouds in the atmosphere the single scattering albedos and backscattering parameters of clouds in each broad spectral interval are giv- en preliminarily and the cloud optical depths are determined according to the cloud liquid water content.展开更多
Tidal stream energy is a type of marine renewable energy which is close to commercial-scale production. Tidal stream turbine arrays are considered as the one of the most promising exploitation methods. However, compar...Tidal stream energy is a type of marine renewable energy which is close to commercial-scale production. Tidal stream turbine arrays are considered as the one of the most promising exploitation methods. However, compared to the relatively mature technology of single turbine design and installation, the current knowledge on the hydrodynamic processes of tidal stream turbine arrays is still limited. Coastal models with simplified turbine representations based on the shallow water equation are among the most favorable methods for studying the tidal stream energy extraction processes in realistic sites. This paper presents a review of the progress and challenges in assessing the tidal stream energy.展开更多
文摘This paper investigates the problem of oblique hydro magnetic stagnation point flow of an electrically conducting Casson fluid over stretching sheet embedded in a doubly stratified medium in the presence of thermal radiation and heat source/absorption with first order chemical reaction.It is assumed that the fluid impinges on the wall obliquely.Similarity variables were used to convert the partial differential equations to ordinary differential equations.The transformed ordinary differential equations are solved numerically using Runge-Kutta-Fehlberg method with shooting technique.It is observed that a boundary layer is formed when the stretching velocity of the surface is less than the in viscid free stream velocity at a point decreases with increase in the non-Newtonian rheology parameter.The augmentation of the temperature is observed with the magnetic parameter,heat source parameter and thermal radiation parameter while a reverse effect with thermal stratification number,Prandtl number and the velocity ratio parameter.Influence of Skin friction coefficient,Nusselt number and Sherwood number on the flow configurations for different values of pertinent parameters are portrayed graphically and discussed.Numerical results are compared with the published results and are found to be in good agreement with previously published results as special cases of present problem.The mass concentration is seen to be decrease with Schmidt number,chemical reaction parameter and solutal stratification number.
文摘Based on the two-stream approximation a broad-band parameterization scheme for solar radiative flux calculation is presented.The whole solar spectral region from 0.2 to 3.58 μm is divided into three broad spectral intervals.The effec- tive broad-band optical depths and single scattering albedos in the atmosphere in each spectral interval can be obtained using parameterized formulae from known atmospheric parameters.The overlapping scattering and/or absorption ef- fects of two atmospheric constituents are considered properly.In the consideration of radiative effect of clouds in the atmosphere the single scattering albedos and backscattering parameters of clouds in each broad spectral interval are giv- en preliminarily and the cloud optical depths are determined according to the cloud liquid water content.
基金Project supported by the National High-Technology Research and Development Program of China(863 Program,Grant No.2012AA052602)
文摘Tidal stream energy is a type of marine renewable energy which is close to commercial-scale production. Tidal stream turbine arrays are considered as the one of the most promising exploitation methods. However, compared to the relatively mature technology of single turbine design and installation, the current knowledge on the hydrodynamic processes of tidal stream turbine arrays is still limited. Coastal models with simplified turbine representations based on the shallow water equation are among the most favorable methods for studying the tidal stream energy extraction processes in realistic sites. This paper presents a review of the progress and challenges in assessing the tidal stream energy.
