Convection in a horizontal fluid layer heated from below is one of models for studying patterns of convection in binary fluid mixtures and has been extensively studied. In this article, the convection structures in a ...Convection in a horizontal fluid layer heated from below is one of models for studying patterns of convection in binary fluid mixtures and has been extensively studied. In this article, the convection structures in a rectangular cell were investigated for the aspect-ratio Г= 12 and the separation ratio ψ = -0.47. Simulations were preformed by solving the hydrodynamic equations using the SIMPLE method. A Counter Propagating Wave （CPW） state was found in binary fluid convection with a periodically horizontal motion of defects, and the pattern dynamics was further discuss.展开更多
In this paper, the convection structure in a rectangular channel with a horizontal flow was studied for the aspect ratio ГA=12 and the separation ratio ψ=-0.11. Our simulations were preformed by solving the hydrodyn...In this paper, the convection structure in a rectangular channel with a horizontal flow was studied for the aspect ratio ГA=12 and the separation ratio ψ=-0.11. Our simulations were preformed by solving the hydrodynamic equations using the SIMPLE method. In the system of binary fluid convection with a horizontal flow, a Periodically Localized Traveling Wave （PLTW） state was found. It has similar behavior to classical Rayleigh-Benard convection in a binary fluid mixture, but the region and wave number of convection change periodically with time. The instability of PLTW depends on the Rayleigh number r and the intensity of horizontal flows Re for given ψ. Thus, the PLTW convection results from the competition between the horizontal flow and the counter-propagating wave near the onset of convection.展开更多
The grid-point atmospheric model of IAP LASG （GAMIL） was developed in and has been evaluated since early 2004. Although the model shows its ability in simulating the global climate, it suffers from some problems in ...The grid-point atmospheric model of IAP LASG （GAMIL） was developed in and has been evaluated since early 2004. Although the model shows its ability in simulating the global climate, it suffers from some problems in simulating precipitation in the tropics. These biases seem to result mainly from the treatment of the subgrid scale convection, which is parameterized with Tiedtke＇s massflux scheme （or the Zhang-McFarlane scheme, as an option） in the model. In order to reduce the systematic biases, several modifications were made to the Tiedtke scheme used in GAMIL, including （1） an increase in lateral convective entrainment/detrainment rate for shallow convection, （2） inclusion of a relative humidity threshold for the triggering of deep convection, and （3） a reduced efficiency for the conversion of cloud water to rainwater in the convection scheme. Two experiments, one with the original Tiedtke scheme used in GAMIL and the other with the modified scheme, were conducted to evaluate the performance of the modified scheme in this study. The results show that both the climatological mean state, such as precipitation, temperature and specific humidity, and interannual variability in the model simulation are improved with the use of this modified scheme. Results from several additional experiments show that the improvements in the model performance in different regions mainly result from either the introduction of the relative humidity threshold for triggering of the deep convection or the suppressed shallow convection due to enhanced lateral convective entrainment/detrainment rates.展开更多
The convection structure in a rectangular channel with a horizontal flow forΓ = 12 was studied. The simulations were preformed by solving the hydrodynamic equations using theSIMPLE method. The convective behavior in ...The convection structure in a rectangular channel with a horizontal flow forΓ = 12 was studied. The simulations were preformed by solving the hydrodynamic equations using theSIMPLE method. The convective behavior in an absolutely and convectively unstable regime wasstudied. The results show that the two types of convection patterns in this system appear dependingon the convection intensity and horizontal flow. A periodically localized traveling wave state wasfound in this system.展开更多
基金the National Natural Science Foundation of China (Grant No. 10872164)the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry (Grant No. 220542)+1 种基金the Key Project of Shanxi Education Committee (Grant No.05JK271)the Scientific Research Foundation of Xi’an University of Technology (Grant No.210532).
文摘Convection in a horizontal fluid layer heated from below is one of models for studying patterns of convection in binary fluid mixtures and has been extensively studied. In this article, the convection structures in a rectangular cell were investigated for the aspect-ratio Г= 12 and the separation ratio ψ = -0.47. Simulations were preformed by solving the hydrodynamic equations using the SIMPLE method. A Counter Propagating Wave （CPW） state was found in binary fluid convection with a periodically horizontal motion of defects, and the pattern dynamics was further discuss.
基金Project supported by SRF for ROCS, SEM(Grant No:220542), the Specific Fund of Higher Educational Doctoral Programme of Xi’an University of Technology (Grant No:220327) and the Key Project of Shaanxi Education Committee(Grant No:05JK271).
文摘In this paper, the convection structure in a rectangular channel with a horizontal flow was studied for the aspect ratio ГA=12 and the separation ratio ψ=-0.11. Our simulations were preformed by solving the hydrodynamic equations using the SIMPLE method. In the system of binary fluid convection with a horizontal flow, a Periodically Localized Traveling Wave （PLTW） state was found. It has similar behavior to classical Rayleigh-Benard convection in a binary fluid mixture, but the region and wave number of convection change periodically with time. The instability of PLTW depends on the Rayleigh number r and the intensity of horizontal flows Re for given ψ. Thus, the PLTW convection results from the competition between the horizontal flow and the counter-propagating wave near the onset of convection.
基金This work is jointly supported by CAS International Partnership Creative Group ＂The Climate System Model Development and Application Studies＂, the 973 Project （Grant No. 2005CB321703） the Fund for Innovative Research Groups （Grant No. 40221503） the National Natural Science Foundation of China （Grant No. 40233031）.
文摘The grid-point atmospheric model of IAP LASG （GAMIL） was developed in and has been evaluated since early 2004. Although the model shows its ability in simulating the global climate, it suffers from some problems in simulating precipitation in the tropics. These biases seem to result mainly from the treatment of the subgrid scale convection, which is parameterized with Tiedtke＇s massflux scheme （or the Zhang-McFarlane scheme, as an option） in the model. In order to reduce the systematic biases, several modifications were made to the Tiedtke scheme used in GAMIL, including （1） an increase in lateral convective entrainment/detrainment rate for shallow convection, （2） inclusion of a relative humidity threshold for the triggering of deep convection, and （3） a reduced efficiency for the conversion of cloud water to rainwater in the convection scheme. Two experiments, one with the original Tiedtke scheme used in GAMIL and the other with the modified scheme, were conducted to evaluate the performance of the modified scheme in this study. The results show that both the climatological mean state, such as precipitation, temperature and specific humidity, and interannual variability in the model simulation are improved with the use of this modified scheme. Results from several additional experiments show that the improvements in the model performance in different regions mainly result from either the introduction of the relative humidity threshold for triggering of the deep convection or the suppressed shallow convection due to enhanced lateral convective entrainment/detrainment rates.
文摘The convection structure in a rectangular channel with a horizontal flow forΓ = 12 was studied. The simulations were preformed by solving the hydrodynamic equations using theSIMPLE method. The convective behavior in an absolutely and convectively unstable regime wasstudied. The results show that the two types of convection patterns in this system appear dependingon the convection intensity and horizontal flow. A periodically localized traveling wave state wasfound in this system.
