scholarly journals Numerical simulation of differential-difference equations with small delay in convective term and reaction term

2021 ◽  
Keyword(s):  
Numerical Simulation ◽  
Difference Equations ◽  
Convective Term ◽  
Reaction Term ◽  
Small Delay

scholarly journals An unconditionally positive and global stability preserving NSFD scheme for an epidemic model with vaccination

2014 ◽  
Vol 24 (3) ◽  
pp. 635-646 ◽  
Author(s):  
Deqiong Ding ◽  
Qiang Ma ◽  
Xiaohua Ding
Keyword(s):  
Numerical Simulation ◽  
Global Stability ◽  
Difference Equations ◽  
Epidemic Model ◽  
Lyapunov Functions ◽  
Numerical Solutions ◽  
Time Step ◽  
The Stability ◽  
Nsfd Scheme ◽  
Nonstandard Finite Difference

Abstract In this paper, a NonStandard Finite Difference (NSFD) scheme is constructed, which can be used to determine numerical solutions for an epidemic model with vaccination. Here the NSFD method is employed to derive a set of difference equations for the epidemic model with vaccination. We show that difference equations have the same dynamics as the original differential system, such as the positivity of the solutions and the stability of the equilibria, without being restricted by the time step. Our proof of global stability utilizes the method of Lyapunov functions. Numerical simulation illustrates the effectiveness of our results

Spectral phase measurement of complex pulses using delay controlled fringe free interferometry technique

2014 ◽  
Vol 23 (02) ◽  
pp. 1450017 ◽  
Author(s):  
Liang Lei ◽  
Xin Liu ◽  
Jin-Hui Wen ◽  
Xiao-Bo Xing ◽  
Bo Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fourier Transform ◽  
Electric Field ◽  
Femtosecond Pulse ◽  
Phase Measurement ◽  
Spectral Phase ◽  
Pulse Measurement ◽  
Field Reconstruction ◽  
Small Delay ◽  
Free Spectra

The shortcomings in complex femtosecond pulse measurement of conventional spectral phase interferometry for direct electric-field reconstruction (SPIDER) are commented in this paper. To solve the problem, we propose an improved version of SPIDER, where single replica of the unknown pulse upconverts synchronously with two frequency-shifted narrow-banded long pulses. With the introduction of a suitable small delay between the upconverted pulses, the spectral phase of the unknown pulse can be directly calculated from the fringe-free spectra and Fourier-transform filtering is not required. The results of numerical simulation show that the accuracy of the new method in complex pulse measurement is higher than conventional SPIDER.

Numerical Simulation of Vortex Shedding and Lock-in Characteristics for a Thin Cambered Blade

2007 ◽  
Vol 129 (10) ◽  
pp. 1297-1305 ◽  
Author(s):  
Baoshan Zhu ◽  
Jun Lei ◽  
Shuliang Cao
Keyword(s):  
Numerical Simulation ◽  
Vortex Shedding ◽  
Forced Oscillation ◽  
Tvd Scheme ◽  
Convective Term ◽  
Variation Diminishing ◽  
Vortex Shedding Frequency ◽  
Shedding Frequency ◽  
Lock In ◽  
Phase Differences

In this paper, vortex-shedding patterns and lock-in characteristics that vortex-shedding frequency synchronizes with the natural frequency of a thin cambered blade were numerically investigated. The numerical simulation was based on solving the vorticity-stream function equations with the fourth-order Runge–Kutta scheme in time and the Chakravaythy–Oscher total variation diminishing (TVD) scheme was used to discretize the convective term. The vortex-shedding patterns for different blade attack angles were simulated. In order to confirm whether the vortex shedding would induce blade self-oscillation, numerical simulation was also carried out for blade in a forced oscillation. By changing the pitching frequency and amplitude, the occurrence of lock-in at certain attack angles was determined. Inside the lock-in zone, phase differences between the blade’s pitching displacement and the torque acting on the blade were used to infer the probability of the blade self-oscillation.

scholarly journals Numerical Simulation of Cyber-physical Biosensor Systems on the Basis of Lattice Difference Equations

2019 ◽  
Vol 4 (2) ◽  
pp. 91-99
Author(s):  
Vasyl Martsenyuk ◽  
◽  
Aleksandra Kłos-Witkowska ◽  
Andriy Sverstiuk ◽  
Oksana Bahrii-Zaiats
Keyword(s):  
Numerical Simulation ◽  
Difference Equations

The Selection of the Difference Scheme in Numerical Simulation of Low-Rise Gable Roof Surface Pressure

2013 ◽  
Vol 711 ◽  
pp. 344-347
Author(s):  
Jian Feng Wu ◽  
Cai Hua Wang ◽  
Xue Qin Zhang
Keyword(s):  
Numerical Simulation ◽  
Surface Wind ◽  
Wind Pressure ◽  
Building Structures ◽  
Convective Term ◽  
Shape Coefficient ◽  
Fluent Software ◽  
The Difference ◽  
Load Shape ◽  
Selection Of

Using the FLUENT software, this paper taking the wind load shape coefficient in the current code for the design of building structures as the comparison standard, have numerical wind tunnel simulation of the wind the surface wind pressure on low layer double slope roof. It focused on the effect of four convective term difference schemes on the numerical simulation, such as First-Order Upwind, Second-Order Upwind, Power Law and Quadratic Upwind Interpolation for ConvectiveKinematics. It provided reasonable reference for selection of convective term difference format.

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