A set of equations was derived for a non-Boussinesq ocean model in thispaper. A new time-splitting scheme was introduced which incorporates the 4th-order Runge-Kuttaexplicit scheme of low-frequency mode and an implici...A set of equations was derived for a non-Boussinesq ocean model in thispaper. A new time-splitting scheme was introduced which incorporates the 4th-order Runge-Kuttaexplicit scheme of low-frequency mode and an implicit scheme of high-frequency mode. With thismodel, potential temperature, salinity fields and sea surface height were calculated simultaneouslysuch that the numerical error of extrapolation of density field from the current time level to thenext one could be reduced while using the equation of mass conservation to determine sea surfaceheight. The non-Bouss-inesq effect on the density field and sea surface height was estimated bynumerical experiments in the final part of this paper.展开更多
The paper presents a novel pressure-corrected formulation of the immersed boundary method(IBM)for the simulation of fully compressible non-Boussinesq natural convection flows.The formulation incorporated into the pres...The paper presents a novel pressure-corrected formulation of the immersed boundary method(IBM)for the simulation of fully compressible non-Boussinesq natural convection flows.The formulation incorporated into the pressure-based fractional step approach facilitates simulation of the flows in the presence of an immersed body characterized by a complex geometry.Here,we first present extensive grid independence and verification studies addressing incompressible pressure-driven flow in an extended channel and non-Boussinesq natural convection flow in a differentially heated cavity.Next,the steady-state non-Boussinesq natural convection flow developing in the presence of hot cylinders of various diameters placed within a cold square cavity is thoroughly investigated.The obtained results are presented and analyzed in terms of the spatial distribution of path lines and temperature fields and of heat flux values typical of the hot cylinder and the cold cavity surfaces.Flow characteristics of multiple steady-state solutions discovered for several configurations are presented and discussed in detail.展开更多
The Pacific Ocean circulations were simulated based on the global warming from 1960 to 1999 by using the Non-Boussinesq POP model and the data of wind stress and temperature at 1 000 hPa from the NCEP. The results sho...The Pacific Ocean circulations were simulated based on the global warming from 1960 to 1999 by using the Non-Boussinesq POP model and the data of wind stress and temperature at 1 000 hPa from the NCEP. The results show that the circulation in the tropical Pacific Ocean was weakening during the past 40 years. The heat transported to the tropical western Pacific Ocean coast by the north equatorial current and the heat transported to middle and high latitudes in the southem hemisphere by the south equatorial current decreased with time due to the global warming, while the heat transported to middle and high latitudes in the northern hemisphere by the north equatorial current increased with time due to the global warming.展开更多
A novel extension to SMAC scheme is proposed for variable density flows under low Mach number approximation. The algorithm is based on a predictor—corrector time integration scheme that employs a projection method fo...A novel extension to SMAC scheme is proposed for variable density flows under low Mach number approximation. The algorithm is based on a predictor—corrector time integration scheme that employs a projection method for the momentum equation. A constant-coefficient Poisson equation is solved for the pressure following both the predictor and corrector steps to satisfy the continuity equation at each time step. The proposed algorithm has second order centrally differenced convective fluxes with upwinding based on Cell Peclet number while diffusive flux are viscous fourth order accurate. Spatial discretization is performed on a collocated grid system that offers computational simplicity and straight forward extension to curvilinear coordinate systems. The algorithm is kinetic energy preserving. Further in this paper robustness and accuracy are demonstrated by performing test on channel flow with non-Boussinesq condition on different temperature ratios.展开更多
文摘A set of equations was derived for a non-Boussinesq ocean model in thispaper. A new time-splitting scheme was introduced which incorporates the 4th-order Runge-Kuttaexplicit scheme of low-frequency mode and an implicit scheme of high-frequency mode. With thismodel, potential temperature, salinity fields and sea surface height were calculated simultaneouslysuch that the numerical error of extrapolation of density field from the current time level to thenext one could be reduced while using the equation of mass conservation to determine sea surfaceheight. The non-Bouss-inesq effect on the density field and sea surface height was estimated bynumerical experiments in the final part of this paper.
基金financial support for this work(grant 218-11-038).
文摘The paper presents a novel pressure-corrected formulation of the immersed boundary method(IBM)for the simulation of fully compressible non-Boussinesq natural convection flows.The formulation incorporated into the pressure-based fractional step approach facilitates simulation of the flows in the presence of an immersed body characterized by a complex geometry.Here,we first present extensive grid independence and verification studies addressing incompressible pressure-driven flow in an extended channel and non-Boussinesq natural convection flow in a differentially heated cavity.Next,the steady-state non-Boussinesq natural convection flow developing in the presence of hot cylinders of various diameters placed within a cold square cavity is thoroughly investigated.The obtained results are presented and analyzed in terms of the spatial distribution of path lines and temperature fields and of heat flux values typical of the hot cylinder and the cold cavity surfaces.Flow characteristics of multiple steady-state solutions discovered for several configurations are presented and discussed in detail.
基金supported by Natural Science Foundation of China (No. 40976015)National Science Foundation for Youth (No. 40906014)
文摘The Pacific Ocean circulations were simulated based on the global warming from 1960 to 1999 by using the Non-Boussinesq POP model and the data of wind stress and temperature at 1 000 hPa from the NCEP. The results show that the circulation in the tropical Pacific Ocean was weakening during the past 40 years. The heat transported to the tropical western Pacific Ocean coast by the north equatorial current and the heat transported to middle and high latitudes in the southem hemisphere by the south equatorial current decreased with time due to the global warming, while the heat transported to middle and high latitudes in the northern hemisphere by the north equatorial current increased with time due to the global warming.
文摘A novel extension to SMAC scheme is proposed for variable density flows under low Mach number approximation. The algorithm is based on a predictor—corrector time integration scheme that employs a projection method for the momentum equation. A constant-coefficient Poisson equation is solved for the pressure following both the predictor and corrector steps to satisfy the continuity equation at each time step. The proposed algorithm has second order centrally differenced convective fluxes with upwinding based on Cell Peclet number while diffusive flux are viscous fourth order accurate. Spatial discretization is performed on a collocated grid system that offers computational simplicity and straight forward extension to curvilinear coordinate systems. The algorithm is kinetic energy preserving. Further in this paper robustness and accuracy are demonstrated by performing test on channel flow with non-Boussinesq condition on different temperature ratios.
