Based on the Zufiria theoretical model, a new model regarding the asymptotic bubble velocity for the Rayleigh-Taylor （RT） instability is presented by use of the complex velocity potential proposed by Sohn. The propo...Based on the Zufiria theoretical model, a new model regarding the asymptotic bubble velocity for the Rayleigh-Taylor （RT） instability is presented by use of the complex velocity potential proposed by Sohn. The proposed model is an extension of the ordinary Zufiria model and can deal with non-ideal fluids. With the control variable method, the effect of the viscosity and surface tension on the bubble growth rate of the RT instability is studied. The result is consistent with Cao＇s result if we only consider the viscous effect and with Xia＇s result if we only consider the surface tension effect. The asymptotic bubble velocity predicted by the Zufiria model is smaller than that predicted by the Layzer model, and the result from the Zufiria model is much closer to White＇s experimental data.展开更多
The Rayleigh–Taylor instability（RTI） in cylindrical geometry is investigated analytically through a second-order weakly nonlinear（WN） theory considering the Bell–Plesset（BP） effect. The governing equations for...The Rayleigh–Taylor instability（RTI） in cylindrical geometry is investigated analytically through a second-order weakly nonlinear（WN） theory considering the Bell–Plesset（BP） effect. The governing equations for the combined perturbation growth are derived. The WN solutions for an exponentially convergent cylinder are obtained. It is found that the BP and RTI growths are strongly coupled, which results in the bubble-spike asymmetric structure in the WN stage. The large Atwood number leads to the large deformation of the convergent interface. The amplitude of the spike grows faster than that of the bubble especially for large mode number m and large Atwood number A. The averaged interface radius is small for large mode number perturbation due to the mode-coupling effect.展开更多
正弦调制靶是瑞利-泰勒(Rayleigh-Taylor,R-T)不稳定性研究的重要实验用靶。从国内外实验用靶的需求出发,采用金刚石车削技术,在紫铜表面完成了振幅为10μm、波长为100μm等一系列正弦曲线的加工。采用直线插补原理编制数控加工程序,利...正弦调制靶是瑞利-泰勒(Rayleigh-Taylor,R-T)不稳定性研究的重要实验用靶。从国内外实验用靶的需求出发,采用金刚石车削技术,在紫铜表面完成了振幅为10μm、波长为100μm等一系列正弦曲线的加工。采用直线插补原理编制数控加工程序,利用超精密金刚石车床,设计了合理的加工工艺过程,分析了对正弦曲线轮廓加工及测量的主要影响因素及误差,通过Form Talysurf series 2型触针式轮廓仪对正弦曲线轮廓进行测量。结果表明:正弦曲线轮廓平滑,波长和振幅数值上与理论值基本相同。通过SPDT技术制备的正弦曲线图形基本满足R-T不稳定性实验需求。展开更多
The present study shows that the Rayleigh–Taylor(RT)instability and its growth rate are strongly dependent on the charge-mass ratio of charged particles in a charged fluid.A higher charge-mass ratio of the charged fl...The present study shows that the Rayleigh–Taylor(RT)instability and its growth rate are strongly dependent on the charge-mass ratio of charged particles in a charged fluid.A higher charge-mass ratio of the charged fluid appears to result in a stronger effect of the magnetic field to suppress the RT instability.We study the RT instabilities for both dusty plasma(small chargemass ratio of charged particles)and ion-electron plasma(large charge-mass ratio of charged particles).It is found that the impact of the external magnetic field to suppress the RT instability for ion-electron plasma is much greater than that for dusty plasma.It is also shown that,for a dusty plasma,in addition to region parameters such as the external magnetic field,region length,its gradient,as well as dust particle parameters such as number density,mass,and charge of dust particles,the growth rate of the RT instability in a dusty plasma also depends on parameters of both electrons and ions such as the number densities and temperatures of both electrons and ions.展开更多
A front tracking method based on a marching cubes isosurface extractor, which is related filter generating isosurfaces from a structured point set, is provided to achieve sharp resolution for the simulation of non-dif...A front tracking method based on a marching cubes isosurface extractor, which is related filter generating isosurfaces from a structured point set, is provided to achieve sharp resolution for the simulation of non-diffusive interfacial flow. Compared with the traditional topology processing procedure, the current front tracking method is easier to be implemented and presents high performance in terms of computational resources. The numerical tests for 2-D highly-shearing flows and 3-D bubbles merging process are conducted to numerically examine the performance of the current methodology for tracking interfaces between two immiscible fluids The Rayleigh-Taylor （RT） and Richtmyer-Meshkov （RM） instability problems are successfully investigated with the present marching cubes based front tracking method.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.11171281 and11201389)
文摘Based on the Zufiria theoretical model, a new model regarding the asymptotic bubble velocity for the Rayleigh-Taylor （RT） instability is presented by use of the complex velocity potential proposed by Sohn. The proposed model is an extension of the ordinary Zufiria model and can deal with non-ideal fluids. With the control variable method, the effect of the viscosity and surface tension on the bubble growth rate of the RT instability is studied. The result is consistent with Cao＇s result if we only consider the viscous effect and with Xia＇s result if we only consider the surface tension effect. The asymptotic bubble velocity predicted by the Zufiria model is smaller than that predicted by the Layzer model, and the result from the Zufiria model is much closer to White＇s experimental data.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11275031,11475034,11575033 and 11274026the National Basic Research Program of China under Grant No 2013CB834100
文摘The Rayleigh–Taylor instability（RTI） in cylindrical geometry is investigated analytically through a second-order weakly nonlinear（WN） theory considering the Bell–Plesset（BP） effect. The governing equations for the combined perturbation growth are derived. The WN solutions for an exponentially convergent cylinder are obtained. It is found that the BP and RTI growths are strongly coupled, which results in the bubble-spike asymmetric structure in the WN stage. The large Atwood number leads to the large deformation of the convergent interface. The amplitude of the spike grows faster than that of the bubble especially for large mode number m and large Atwood number A. The averaged interface radius is small for large mode number perturbation due to the mode-coupling effect.
文摘正弦调制靶是瑞利-泰勒(Rayleigh-Taylor,R-T)不稳定性研究的重要实验用靶。从国内外实验用靶的需求出发,采用金刚石车削技术,在紫铜表面完成了振幅为10μm、波长为100μm等一系列正弦曲线的加工。采用直线插补原理编制数控加工程序,利用超精密金刚石车床,设计了合理的加工工艺过程,分析了对正弦曲线轮廓加工及测量的主要影响因素及误差,通过Form Talysurf series 2型触针式轮廓仪对正弦曲线轮廓进行测量。结果表明:正弦曲线轮廓平滑,波长和振幅数值上与理论值基本相同。通过SPDT技术制备的正弦曲线图形基本满足R-T不稳定性实验需求。
基金the National Natural Science Foundation of China(Nos.12275223,11965019)the Foundation of Gansu Educational Committee(No.2022QB-178)。
文摘The present study shows that the Rayleigh–Taylor(RT)instability and its growth rate are strongly dependent on the charge-mass ratio of charged particles in a charged fluid.A higher charge-mass ratio of the charged fluid appears to result in a stronger effect of the magnetic field to suppress the RT instability.We study the RT instabilities for both dusty plasma(small chargemass ratio of charged particles)and ion-electron plasma(large charge-mass ratio of charged particles).It is found that the impact of the external magnetic field to suppress the RT instability for ion-electron plasma is much greater than that for dusty plasma.It is also shown that,for a dusty plasma,in addition to region parameters such as the external magnetic field,region length,its gradient,as well as dust particle parameters such as number density,mass,and charge of dust particles,the growth rate of the RT instability in a dusty plasma also depends on parameters of both electrons and ions such as the number densities and temperatures of both electrons and ions.
基金supported by the National Natural Science Foundation of China (Grant No. 10702064)
文摘A front tracking method based on a marching cubes isosurface extractor, which is related filter generating isosurfaces from a structured point set, is provided to achieve sharp resolution for the simulation of non-diffusive interfacial flow. Compared with the traditional topology processing procedure, the current front tracking method is easier to be implemented and presents high performance in terms of computational resources. The numerical tests for 2-D highly-shearing flows and 3-D bubbles merging process are conducted to numerically examine the performance of the current methodology for tracking interfaces between two immiscible fluids The Rayleigh-Taylor （RT） and Richtmyer-Meshkov （RM） instability problems are successfully investigated with the present marching cubes based front tracking method.
