Numerical simulations have been carried out for laminar sinusoidal pulsating flow in a tube with smooth single constriction.A second-order finite volume method has been developed to solve the fluid flow governing equa...Numerical simulations have been carried out for laminar sinusoidal pulsating flow in a tube with smooth single constriction.A second-order finite volume method has been developed to solve the fluid flow governing equations on a nonstaggered non-orthogonal grid.The effects of the Reynolds number,the Womersley number,the pulsatile amplitude,the constriction ratio and the constriction length on fluid flow in constricted tube will be investigated.It will be demonstrated that the dynamic nature of the pulsating flow greatly depends on the frequency of the flow changes.It is observed that the peak wall vorticity seems to increase with the increase of Reynolds number,the pulsating amplitude and the constriction ratio.The peak values of instantaneous wall vorticity are not greatly affected by the variation of Womersly number.The constriction length does not put a significant impact on the flow instantaneous streamline behaviors compared with other parameters.However,the peak wall vorticity increases monotonically with the decrease of the constriction length.展开更多
In this study,a stable and robust interface-capturing method is developed to resolve inviscid,compressible two-fluid flows with general equation of state(EOS).The governing equations consist of mass conservation equat...In this study,a stable and robust interface-capturing method is developed to resolve inviscid,compressible two-fluid flows with general equation of state(EOS).The governing equations consist of mass conservation equation for each fluid,momentum and energy equations for mixture and an advection equation for volume fraction of one fluid component.Assumption of pressure equilibrium across an interface is used to close the model system.MUSCL-Hancock scheme is extended to construct input states for Riemann problems,whose solutions are calculated using generalized HLLC approximate Riemann solver.Adaptive mesh refinement(AMR)capability is built into hydrodynamic code.The resulting method has some advantages.First,it is very stable and robust,as the advection equation is handled properly.Second,general equation of state can model more materials than simple EOSs such as ideal and stiffened gas EOSs for example.In addition,AMR enables us to properly resolve flow features at disparate scales.Finally,this method is quite simple,time-efficient and easy to implement.展开更多
文摘Numerical simulations have been carried out for laminar sinusoidal pulsating flow in a tube with smooth single constriction.A second-order finite volume method has been developed to solve the fluid flow governing equations on a nonstaggered non-orthogonal grid.The effects of the Reynolds number,the Womersley number,the pulsatile amplitude,the constriction ratio and the constriction length on fluid flow in constricted tube will be investigated.It will be demonstrated that the dynamic nature of the pulsating flow greatly depends on the frequency of the flow changes.It is observed that the peak wall vorticity seems to increase with the increase of Reynolds number,the pulsating amplitude and the constriction ratio.The peak values of instantaneous wall vorticity are not greatly affected by the variation of Womersly number.The constriction length does not put a significant impact on the flow instantaneous streamline behaviors compared with other parameters.However,the peak wall vorticity increases monotonically with the decrease of the constriction length.
文摘In this study,a stable and robust interface-capturing method is developed to resolve inviscid,compressible two-fluid flows with general equation of state(EOS).The governing equations consist of mass conservation equation for each fluid,momentum and energy equations for mixture and an advection equation for volume fraction of one fluid component.Assumption of pressure equilibrium across an interface is used to close the model system.MUSCL-Hancock scheme is extended to construct input states for Riemann problems,whose solutions are calculated using generalized HLLC approximate Riemann solver.Adaptive mesh refinement(AMR)capability is built into hydrodynamic code.The resulting method has some advantages.First,it is very stable and robust,as the advection equation is handled properly.Second,general equation of state can model more materials than simple EOSs such as ideal and stiffened gas EOSs for example.In addition,AMR enables us to properly resolve flow features at disparate scales.Finally,this method is quite simple,time-efficient and easy to implement.
