scholarly journals Стационарные и самоподобные волны в стержне с разномодульной нелинейностью, диссипацией и дисперсией

2020 ◽  
Vol 90 (1) ◽  
pp. 11
Author(s):  
В.Е. Назаров ◽  
С.Б. Кияшко
Keyword(s):  
Phase Velocity ◽  
Elastic Waves ◽  
Numerical Solutions ◽  
Graphical Analysis ◽  
Stationary Waves ◽  
Periodic Waves ◽  
Analytical And Numerical Solutions ◽  
Self Similar ◽  
Impulsive Perturbations

STATIONARY AND SELF-SIMILAR WAVES IN A ROD WITH BIMODULAR NONLINEARITY, DISSIPATION AND DISPERSION V.E.Nazarov, S.B.Kiyasko The propagation of longitudinal elastic waves in a rod with bimodular nonlinearity, linear dissipation and geometric dispersion of the phase velocity is investigated. Analytical and numerical solutions for the profiles of stationary waves and self-similar periodic waves and impulsive perturbations propagating in such rod without changing the shape are obtained; their graphical analysis was carried out.

Comparison of the numerical and self-similar solutions of Sedov’s problem on a point explosion in gas

2020 ◽  
Vol 15 (3-4) ◽  
pp. 212-216
Author(s):  
R.Kh. Bolotnova ◽  
V.A. Korobchinskaya
Keyword(s):  
Gas Dynamics ◽  
Numerical Solutions ◽  
Similarity Theory ◽  
Compressible Medium ◽  
Initial Moment ◽  
Point Explosion ◽  
Perfect Gas ◽  
Gas Dynamics Equations ◽  
Self Similar ◽  
Similar Solutions

Comparative analysis of solutions of Sedov’s problem of a point explosion in gas for the plane case, obtained by the analytical method and using the open software package of computational fluid dynamics OpenFOAM, is carried out. A brief analysis of methods of dimensionality and similarity theory used for the analytical self-similar solution of point explosion problem in a perfect gas (nitrogen) which determined by the density of uncompressed gas, magnitude of released energy, ratio of specific heat capacities and by the index of geometry of the explosion is given. The system of one-dimensional gas dynamics equations for a perfect gas includes the laws of conservation of mass, momentum, and energy is used. It is assumed that at the initial moment of time there is a point explosion with instantaneous release of energy. Analytical self-similar solutions for the Euler and Lagrangian coordinates, mass velocity, pressure, temperature, and density in the case of plane geometry are given. The numerical simulation of considered process in sonicFoam solver of OpenFOAM package built on the PISO algorithm was performed. For numerical modeling the system of differential equations of gas dynamics is used, including the equations of continuity, Navier-Stokes motion for a compressible medium and conservation of internal energy. Initial and boundary conditions were selected in accordance with the obtained analytical solution using the setFieldsDict, blockMeshDict, and uniformFixedValue utilities. The obtained analytical and numerical solutions have a satisfactory agreement.

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