We extend two adaptive step-size methods for solving two-dimensional or multi-dimensional generalized nonlinear Schr ¨odinger equation(GNLSE): one is the conservation quantity error adaptive step-control method(R...We extend two adaptive step-size methods for solving two-dimensional or multi-dimensional generalized nonlinear Schr ¨odinger equation(GNLSE): one is the conservation quantity error adaptive step-control method(RK4IP-CQE), and the other is the local error adaptive step-control method(RK4IP-LEM). The methods are developed in the vector form of fourthorder Runge–Kutta iterative scheme in the interaction picture by converting a vector equation in frequency domain. By simulating the supercontinuum generated from the high birefringence photonic crystal fiber, the calculation accuracies and the efficiencies of the two adaptive step-size methods are discussed. The simulation results show that the two methods have the same global average error, while RK4IP-LEM spends more time than RK4IP-CQE. The decrease of huge calculation time is due to the differences in the convergences of the relative photon number error and the approximated local error between these two adaptive step-size algorithms.展开更多
The uniform mixing of solids is important in many industries,such as the pharmaceutical,food,petrochemical and chemical industries.We numerically investigated the effect of particle size ratio on the mixing of bisized...The uniform mixing of solids is important in many industries,such as the pharmaceutical,food,petrochemical and chemical industries.We numerically investigated the effect of particle size ratio on the mixing of bisized particles in a quasi-two-dimensional vibrationally fluidized bed.The granular bin ary mixtures comprised spherical particles with different size ratios.Three-dimensional discrete-element simulations agreed with previous experimental results.Convective and diffusive mechanisms occurred Keywords:Discrete-element modeling Fluidization Granular media Mixing Particle size ratio Vibration within the vibrated bed.The particle size had no significant influence on convective mixing,whereas the diffusive mechanism strengthened for large size ratios.The average particle velocity was larger in a mixture of large size ratios.The stronger diffusive motion and larger average particle velocity caused the particles to mix faster for large size ratios.The final mixing index decreased with size ratio because of the difference between the size and number of small and large particles.展开更多
Soil is a typical porous media and its impedance characteristic directly determines the performance of grounding system. Soil phase frequency characteristic measurements were carried out on various soil types and wate...Soil is a typical porous media and its impedance characteristic directly determines the performance of grounding system. Soil phase frequency characteristic measurements were carried out on various soil types and water content. This paper finds that the impedance angle of soil specimen presents a capacitive performance when power frequency (f) is low. As the frequency increases, soil impedance angle goes up rapidly. Furthermore the frequency characteristic while f > 1000 Hz is distinct in terms of different water content. In particular, at low moisture content, soil impedance angle would be higher than 0?, that is, the inductive component is obvious. The study result indicates that porous media possesses the unique conductivity property dif-ferent from conductor and solution. Its mechanism needs further study.展开更多
基金supported by the National Key Research and Development Program of China (Grant Nos. 2021YFC2201803 and 2020YFC2200104)。
文摘We extend two adaptive step-size methods for solving two-dimensional or multi-dimensional generalized nonlinear Schr ¨odinger equation(GNLSE): one is the conservation quantity error adaptive step-control method(RK4IP-CQE), and the other is the local error adaptive step-control method(RK4IP-LEM). The methods are developed in the vector form of fourthorder Runge–Kutta iterative scheme in the interaction picture by converting a vector equation in frequency domain. By simulating the supercontinuum generated from the high birefringence photonic crystal fiber, the calculation accuracies and the efficiencies of the two adaptive step-size methods are discussed. The simulation results show that the two methods have the same global average error, while RK4IP-LEM spends more time than RK4IP-CQE. The decrease of huge calculation time is due to the differences in the convergences of the relative photon number error and the approximated local error between these two adaptive step-size algorithms.
文摘The uniform mixing of solids is important in many industries,such as the pharmaceutical,food,petrochemical and chemical industries.We numerically investigated the effect of particle size ratio on the mixing of bisized particles in a quasi-two-dimensional vibrationally fluidized bed.The granular bin ary mixtures comprised spherical particles with different size ratios.Three-dimensional discrete-element simulations agreed with previous experimental results.Convective and diffusive mechanisms occurred Keywords:Discrete-element modeling Fluidization Granular media Mixing Particle size ratio Vibration within the vibrated bed.The particle size had no significant influence on convective mixing,whereas the diffusive mechanism strengthened for large size ratios.The average particle velocity was larger in a mixture of large size ratios.The stronger diffusive motion and larger average particle velocity caused the particles to mix faster for large size ratios.The final mixing index decreased with size ratio because of the difference between the size and number of small and large particles.
文摘Soil is a typical porous media and its impedance characteristic directly determines the performance of grounding system. Soil phase frequency characteristic measurements were carried out on various soil types and water content. This paper finds that the impedance angle of soil specimen presents a capacitive performance when power frequency (f) is low. As the frequency increases, soil impedance angle goes up rapidly. Furthermore the frequency characteristic while f > 1000 Hz is distinct in terms of different water content. In particular, at low moisture content, soil impedance angle would be higher than 0?, that is, the inductive component is obvious. The study result indicates that porous media possesses the unique conductivity property dif-ferent from conductor and solution. Its mechanism needs further study.
