Two-dimensional Navier-Stokes equations and energy equation governing incompressible laminar flow past a bundle of cylinders were numerically solved by using the finite element method. The velocity correction method w...Two-dimensional Navier-Stokes equations and energy equation governing incompressible laminar flow past a bundle of cylinders were numerically solved by using the finite element method. The velocity correction method was used for time advancement, and spatial discretization was carried out with the Galerkin weighted residual method. Viscous flows past the cylinder banks arranged in in-line cylinder bundles and staggered cylinder bundles, coupled with heat transfer, were investigated for pitch-diameter ratios of 1.5 and 2.0 and the Reynolds numbers from 50 to 500. Flow structures and heat transfer behavior were discussed. The results obtained agree well with available numerical data.展开更多
For two-dimensional wa ter flow in open channel, by discritizing hydrodynamic differential equation of conservative form, the corresponding algebraic equations were derived which invo lve the relationship between vel...For two-dimensional wa ter flow in open channel, by discritizing hydrodynamic differential equation of conservative form, the corresponding algebraic equations were derived which invo lve the relationship between velocity and depth. Based on the relationship, this paper deduced a modified formula of velocity correction for SIMPLE algorithm. A s a test case, the flow in a prismatic channel with two different slopes was com puted and a good result was obtained.展开更多
A boundary condition-implemented immersed boundary-lattice Boltzmann method(IB-LBM)is presented in this work.The present approach is an improvement to the conventional IB-LBM.In the conventional IB-LBM,the no-slip bou...A boundary condition-implemented immersed boundary-lattice Boltzmann method(IB-LBM)is presented in this work.The present approach is an improvement to the conventional IB-LBM.In the conventional IB-LBM,the no-slip boundary condition is only approximately satisfied.As a result,there is flow penetration to the solid boundary.Another drawback of conventional IB-LBM is the use of Dirac delta function interpolation,which only has the first order of accuracy.In this work,the no-slip boundary condition is directly implemented,and used to correct the velocity at two adjacent mesh points from both sides of the boundary point.The velocity correction is made through the second-order polynomial interpolation rather than the first-order delta function interpolation.Obviously,the two drawbacks of conventional IB-LBM are removed in the present study.Another important contribution of this paper is to present a simple way to compute the hydrodynamic forces on the boundary from Newton’s second law.To validate the proposed method,the two-dimensional vortex decaying problem and incompressible flow over a circular cylinder are simulated.As shown in the present results,the flow penetration problem is eliminated,and the obtained results compare very well with available data in the literature.展开更多
基金The project supported by the Natural Science Foundation of China.(No.19889210)
文摘Two-dimensional Navier-Stokes equations and energy equation governing incompressible laminar flow past a bundle of cylinders were numerically solved by using the finite element method. The velocity correction method was used for time advancement, and spatial discretization was carried out with the Galerkin weighted residual method. Viscous flows past the cylinder banks arranged in in-line cylinder bundles and staggered cylinder bundles, coupled with heat transfer, were investigated for pitch-diameter ratios of 1.5 and 2.0 and the Reynolds numbers from 50 to 500. Flow structures and heat transfer behavior were discussed. The results obtained agree well with available numerical data.
文摘For two-dimensional wa ter flow in open channel, by discritizing hydrodynamic differential equation of conservative form, the corresponding algebraic equations were derived which invo lve the relationship between velocity and depth. Based on the relationship, this paper deduced a modified formula of velocity correction for SIMPLE algorithm. A s a test case, the flow in a prismatic channel with two different slopes was com puted and a good result was obtained.
基金supported by the National Natural Science Foundation of China(11272153).
文摘A boundary condition-implemented immersed boundary-lattice Boltzmann method(IB-LBM)is presented in this work.The present approach is an improvement to the conventional IB-LBM.In the conventional IB-LBM,the no-slip boundary condition is only approximately satisfied.As a result,there is flow penetration to the solid boundary.Another drawback of conventional IB-LBM is the use of Dirac delta function interpolation,which only has the first order of accuracy.In this work,the no-slip boundary condition is directly implemented,and used to correct the velocity at two adjacent mesh points from both sides of the boundary point.The velocity correction is made through the second-order polynomial interpolation rather than the first-order delta function interpolation.Obviously,the two drawbacks of conventional IB-LBM are removed in the present study.Another important contribution of this paper is to present a simple way to compute the hydrodynamic forces on the boundary from Newton’s second law.To validate the proposed method,the two-dimensional vortex decaying problem and incompressible flow over a circular cylinder are simulated.As shown in the present results,the flow penetration problem is eliminated,and the obtained results compare very well with available data in the literature.
