scholarly journals NON-LINEAR WKB ANALYSIS OF THE STRING EQUATION

1992 ◽  
Vol 06 (11n12) ◽  
pp. 2123-2147 ◽  
Author(s):  
F. FUCITO ◽  
A. GAMBA ◽  
M. MARTELLINI ◽  
O. RAGNISCO
Keyword(s):  
Numerical Simulations ◽  
Numerical Solution ◽  
Excellent Agreement ◽  
Riemann Surfaces ◽  
Analytic Approximation ◽  
String Equation ◽  
Non Linear

We apply non-linear WKB analysis to the study of the string equation. Even though the solutions obtained with this method are not exact, they approximate extremely well the true solutions, as we explicitly show using numerical simulations. “Physical” solutions are seen to be separatrices corresponding to degenerate Riemann surfaces. We obtain an analytic approximation in excellent agreement with the numerical solution found by Parisi et al. for the k=3 case.

ON THE STRING EQUATION AND THE WHITHAM METHOD

1993 ◽  
Vol 08 (19) ◽  
pp. 3321-3338 ◽  
Author(s):  
F. FUCITO ◽  
A. GAMBA ◽  
M. MARTELLINI
Keyword(s):  
Numerical Simulations ◽  
Excellent Agreement ◽  
String Equation ◽  
Detailed Report ◽  
Whitham Method

We present a detailed report of the application of the Whitham method to the study of the string equation. Even though the solutions obtained with this method are not exact they are in excellent agreement with the true solutions, as we explicitly show using numerical simulations.

Motion of a Large Dusty Buoyant Thermal With a Vortex Ring

1978 ◽  
Vol 45 (4) ◽  
pp. 711-716 ◽  
Author(s):  
Stephen S.-H. Chang
Keyword(s):  
Numerical Solution ◽  
Vortex Ring ◽  
Excellent Agreement ◽  
Spherical Particles ◽  
System Of Equations ◽  
Inhomogeneous Atmosphere

This paper presents a method for computing the motion and decay of a large dusty, buoyant thermal (cloud) carried by a vortex ring generated from a strong near ground explosion and ascending in an inhomogeneous atmosphere. A system of equations is derived describing the motion of the vortex ring, the thermal, and the pollutants which consist of numerous solid spherical particles. The interior properties and the trajectories of the thermal and the pollutants are obtained. The numerical solution for the thermal trajectory is in excellent agreement with experiment.

The Best Perturbation Method for the Parameter Inversion of Two-Dimension Convection-Diffusion Equation

2013 ◽  
Vol 380-384 ◽  
pp. 1143-1146
Author(s):  
Xiang Guo Liu
Keyword(s):  
Inverse Problem ◽  
Diffusion Equation ◽  
Perturbation Method ◽  
Numerical Simulations ◽  
Numerical Solution ◽  
Two Dimensional ◽  
Convection Diffusion ◽  
Convection Diffusion Equation ◽  
Parameter Inversion ◽  
Parametric Inversion

The paper researches the parametric inversion of the two-dimensional convection-diffusion equation by means of best perturbation method, draw a Numerical Solution for such inverse problem. It is shown by numerical simulations that the method is feasible and effective.

Numerical Simulations as a Reliable Alternative for Landmine Explosion Studies: The AUTODYN Approach

2010 ◽  
Author(s):  
Stephanie Follett ◽  
Amer Hameed ◽  
S. Darina ◽  
John G. Hetherington
Keyword(s):  
Experimental Data ◽  
Numerical Simulations ◽  
Reasonable Agreement ◽  
Specific Impulse ◽  
Numerical Procedure ◽  
Ground Surface ◽  
Time Of Arrival ◽  
Linear Dynamics ◽  
Non Linear

In order to validate the numerical procedure, the explosion of a mine was recreated within the non-linear dynamics software, AUTODYN. Two models were created and analysed for the purposes of this study — buried and flush HE charge in sand. The explosion parameters — time of arrival, maximum overpressure and specific impulse were recorded at two stand-off distances above the ground surface. These parameters are then compared with LS-DYNA models and published experimental data. The results, presented in table format, are in reasonable agreement.

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