scholarly journals Formation of singularities in one-dimensional Chaplygin gas

2014 ◽  
Vol 11 (03) ◽  
pp. 521-561 ◽  
Author(s):  
De-Xing Kong ◽  
Changhua Wei ◽  
Qiang Zhang

We investigate the formation and propagation of singularities for the system of one-dimensional Chaplygin gas. Under suitable assumptions we construct a physically meaningful solution containing a new type of singularities called "delta-like" solution for this kind of quasilinear hyperbolic system with linearly degenerate characteristics. By a careful analysis, we study the behavior of the solution in a neighborhood of a blow-up point. The formation of this new kind of singularities is related to the envelop of different characteristic families, instead of characteristics of the same family in the standard situation. This shows that the blow-up phenomenon for systems with linearly degenerate characteristics is quite different from the problem of shock formation for the system with genuinely nonlinear characteristic fields. Different initial data can lead to different delta-like singularities: the delta-like singularity with point-shape and the delta-like singularity with line-shape.

2020 ◽  
Vol 20 (4) ◽  
pp. 739-767
Author(s):  
Azahara DelaTorre ◽  
Gabriele Mancini ◽  
Angela Pistoia

AbstractWe study the existence of sign-changing solutions for a non-local version of the sinh-Poisson equation on a bounded one-dimensional interval I, under Dirichlet conditions in the exterior of I. This model is strictly related to the mathematical description of galvanic corrosion phenomena for simple electrochemical systems. By means of the finite-dimensional Lyapunov–Schmidt reduction method, we construct bubbling families of solutions developing an arbitrarily prescribed number sign-alternating peaks. With a careful analysis of the limit profile of the solutions, we also show that the number of nodal regions coincides with the number of blow-up points.


2021 ◽  
Vol 11 (2) ◽  
pp. 609
Author(s):  
Tadeusz Chyży ◽  
Monika Mackiewicz

The conception of special finite elements called multi-area elements for the analysis of structures with different stiffness areas has been presented in the paper. A new type of finite element has been determined in order to perform analyses and calculations of heterogeneous, multi-coherent, and layered structures using fewer finite elements and it provides proper accuracy of the results. The main advantage of the presented special multi-area elements is the possibility that areas of the structure with different stiffness and geometrical parameters can be described by single element integrated in subdivisions (sub-areas). The formulation of such elements has been presented with the example of one-dimensional elements. The main idea of developed elements is the assumption that the deformation field inside the element is dependent on its geometry and stiffness distribution. The deformation field can be changed and adjusted during the calculation process that is why such elements can be treated as self-adaptive. The application of the self-adaptation method on strain field should simplify the analysis of complex non-linear problems and increase their accuracy. In order to confirm the correctness of the established assumptions, comparative analyses have been carried out and potential areas of application have been indicated.


2008 ◽  
Vol 63 (16) ◽  
pp. 4159-4170 ◽  
Author(s):  
Alessandro Butté ◽  
Giuseppe Storti ◽  
Marco Mazzotti

2019 ◽  
Vol 16 (04) ◽  
pp. 639-661 ◽  
Author(s):  
Zhen Wang ◽  
Xinglong Wu

We establish a well-posedness theory and a blow-up criterion for the Chaplygin gas equations in [Formula: see text] for any dimension [Formula: see text]. First, given [Formula: see text], [Formula: see text], we prove the well-posedness property for solutions [Formula: see text] in the space [Formula: see text] for the Cauchy problem associated with the Chaplygin gas equations, provided the initial density [Formula: see text] is bounded below. We also prove that the solution of the Chaplygin gas equations depends continuously upon its initial data [Formula: see text] in [Formula: see text] if [Formula: see text], and we state a blow-up criterion for the solutions in the classical BMO space. Finally, using Osgood’s modulus of continuity, we establish a refined blow-up criterion of the solutions.


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