In this paper,we consider the double-satellite localization under the earth ellipsoid model of the Wideband Geodetic System(WGS-84)using the Time Difference of Arrival(TDOA)and the Angle-of-Arrival(AOA).Several closed...In this paper,we consider the double-satellite localization under the earth ellipsoid model of the Wideband Geodetic System(WGS-84)using the Time Difference of Arrival(TDOA)and the Angle-of-Arrival(AOA).Several closed-form solution algorithms via the pseudolinearization of the measurement equations are presented to efficiently estimate the location.These algorithms include the Weighted Least Squares(WLS),the Constrained Total Least Squares(CTLS),and the Taylor-Series Iteration(TSI).Performance comparison of the proposed methods with the Cramér-Rao Lower Bound(CRLB)in the simulation is shown to demonstrate that the proposed algorithms are feasible and have stable performance.展开更多
A CFD simulation is performed for a particle-laden planar jet flow.The Reynolds number is 8300,and the initial particle diameter is 1 μm.Large Eddy Simulation（LES） is employed to calculate the flow field,and the Ta...A CFD simulation is performed for a particle-laden planar jet flow.The Reynolds number is 8300,and the initial particle diameter is 1 μm.Large Eddy Simulation（LES） is employed to calculate the flow field,and the Taylor-series expansion moment method（TEMOM） is adopted to deal with the balance equation of particle coagulation and breakage.The shear-induced coagulation kernel,power-law breakage kernel and symmetric fragment distribution function are involved.The prediction of the distribution of the mean streamwise velocity of the jet is in good agreement with experimental data.The evolution of particle number concentration,volume concentration,polydispersity,particle diameter and standard geometric deviation is discussed in detail.The results show that as the jet travels downstream,the particle number concentration and volume concentration decrease,while their spans become wider.The polydispersity and particle diameter are very large in the shear layers at the upstream and in the core of vortex structures at the downstream.The particle standard geometric deviation changes within the range of 1.32 ≤σg≤ 1.96,and increases sharply in the shear layers.All variables approach the steady-state as time progresses.展开更多
In this article,a coupling of the direct numerical simulation(DNS)and the population balance modeling(PBM)is implemented to study the effect of turbulence on nanoparticle dynamics in homogenous isotropic turbulence(HI...In this article,a coupling of the direct numerical simulation(DNS)and the population balance modeling(PBM)is implemented to study the effect of turbulence on nanoparticle dynamics in homogenous isotropic turbulence(HIT).The DNS is implemented based on a pseudo-spectral method and the PBM is implemented using the Taylor-series expansion method of moments.The result verifies that coagulation due to turbulent shear force has a bigger impact on the evolution of number concentration,polydispersity,and average diameter of nanoparticles than Brownian coagulation in the HIT.The Reynolds number plays an important role in determining the number concentration,polydispersity,and average diameter of nanoparticles,and these quantities change more rapidly with an increase of Reynolds number.It is also found that the initial geometric standard deviation slows down the evolution of particle dynamics,but almost has no influence on the polydispersity of nanoparticles.展开更多
基金supported by Meteorological information and Signal Processing Key Laboratory of Sichuan Higher Education Institutes of Chengdu University of Information Technology,China(No.QXXCSYS201702)
文摘In this paper,we consider the double-satellite localization under the earth ellipsoid model of the Wideband Geodetic System(WGS-84)using the Time Difference of Arrival(TDOA)and the Angle-of-Arrival(AOA).Several closed-form solution algorithms via the pseudolinearization of the measurement equations are presented to efficiently estimate the location.These algorithms include the Weighted Least Squares(WLS),the Constrained Total Least Squares(CTLS),and the Taylor-Series Iteration(TSI).Performance comparison of the proposed methods with the Cramér-Rao Lower Bound(CRLB)in the simulation is shown to demonstrate that the proposed algorithms are feasible and have stable performance.
基金supported by the National Natural Science Foundation of China (Grant No. 10632070)
文摘A CFD simulation is performed for a particle-laden planar jet flow.The Reynolds number is 8300,and the initial particle diameter is 1 μm.Large Eddy Simulation（LES） is employed to calculate the flow field,and the Taylor-series expansion moment method（TEMOM） is adopted to deal with the balance equation of particle coagulation and breakage.The shear-induced coagulation kernel,power-law breakage kernel and symmetric fragment distribution function are involved.The prediction of the distribution of the mean streamwise velocity of the jet is in good agreement with experimental data.The evolution of particle number concentration,volume concentration,polydispersity,particle diameter and standard geometric deviation is discussed in detail.The results show that as the jet travels downstream,the particle number concentration and volume concentration decrease,while their spans become wider.The polydispersity and particle diameter are very large in the shear layers at the upstream and in the core of vortex structures at the downstream.The particle standard geometric deviation changes within the range of 1.32 ≤σg≤ 1.96,and increases sharply in the shear layers.All variables approach the steady-state as time progresses.
基金Project supported by the Zhejiang Provincial Natural Science Foundation of China(grant number,LR16A020002)the National Natural Science Foundation of China(grant number,11872353 and 91852102).
文摘In this article,a coupling of the direct numerical simulation(DNS)and the population balance modeling(PBM)is implemented to study the effect of turbulence on nanoparticle dynamics in homogenous isotropic turbulence(HIT).The DNS is implemented based on a pseudo-spectral method and the PBM is implemented using the Taylor-series expansion method of moments.The result verifies that coagulation due to turbulent shear force has a bigger impact on the evolution of number concentration,polydispersity,and average diameter of nanoparticles than Brownian coagulation in the HIT.The Reynolds number plays an important role in determining the number concentration,polydispersity,and average diameter of nanoparticles,and these quantities change more rapidly with an increase of Reynolds number.It is also found that the initial geometric standard deviation slows down the evolution of particle dynamics,but almost has no influence on the polydispersity of nanoparticles.
