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L. Mátyás

Publications and source records attributed to L. Mátyás.

8 recordsLinked to original sources
arXiv2023

Analytical investigation of time-dependent two-dimensional non-Newtonian boundary layer equations

In this study, five different time-dependent incompressible non-Newtonian boundary layer models in two dimensions are investigated, including external magnetic field effects. The power law, the Casson fluid, the Oldroyd-B model, the Walter fluid B model and the Williamson fluid are analyzed. For the first two models, analytical results are given for the velocity and pressure distributions, which can be expressed by different types of hypergeometric functions. Depending on the parameters involved in the analytical solutions of the nonlinear ordinary differential equation obtained by the similarity transformation, a very wide range of solution types is presented.

physics.flu-dyn↗
arXiv2023

Even and odd self-similar solutions of the diffusion equation for infinite horizon

In the description of transport phenomena an important aspect represents the diffusion. In certain cases the diffusion may appear together with convection. In this paper we study the diffusion equation with the self similar Ansatz. With an appropriate change of variables we found original solutions of diffusion equation for infinite horizon. Here we present the even solutions of diffusion equation for the boundary conditions presented. For completeness the odd solutions are also mentioned as well, as part of the previous works. Finally, the diffusion equation with constant source term is discussed, which also has even and odd solutions, too

physics.class-ph↗
arXiv2022

Time-dependent analytic solutions for water waves above sea of varying depths

We investigate a hydrodynamic equation system which - with some approximation - is capable to describe the tsunami propagation in the open ocean with the time-dependent self-similar Ansatz. We found analytic solutions how the wave height and velocity behave in time and space for constant and linear seabed functions. First we study waves on open water, where the seabed can be considered relatively constant, sufficiently far from the shore. In the second part of the study we also consider a seabed which is oblique. Finally, we apply the most common traveling wave Ansatz and present almost trivial solutions as well.

nlin.SI↗
arXiv2021

General self-similar solutions of diffusion equation and related constructions

Transport phenomena plays an important role in science and technology. In the wide variety of applications both advection and diffusion may appear. Regarding diffusion, for long times, different type of decay rates are possible for different non-equilibrium systems. After summarizing the existing solutions of the regular diffusion equation, we present not so well known solution derived from three different trial functions, as a key point we present a family of solutions for the case of infinite horizon. By this we tried to make a step toward understanding the different long time decays for different diffusive systems.

physics.class-ph↗
arXiv2021

Self-similar analysis of the time-dependent compressible and incompressible boundary layers including heat conduction

We investigate the incompressible and compressible heat conducting boundary layer with applying the two-dimensional self-similar Ansatz. Analytic solutions can be found for the incompressible case which can be expressed with special functions. The parameter dependencies are studied and discussed in details. In the last part of our study we present the ordinary differential equation (ODE) system which is obtained for compressible boundary layers.

physics.flu-dyn↗
arXiv2018

Self-similarity analysis of the non-linear Schrödinger equation in the Madelung form

In the present study a particular case of Gross-Pitaevskii or non-linear Schrödinger equation is rewritten to a form similar to a hydrodynamic Euler equation using the Madelung transformation. The obtained system of differential equations is highly nonlinear. Regarding solutions, a larger coefficient of the nonlinear term yields stronger deviation of the solution from the linear case.

quant-ph↗
arXiv2010

Geometrical origin of chaoticity in the bouncing ball billiard

We present a study of the chaotic behavior of the bouncing ball billiard. The work is realised on the purpose of finding at least certain causes of separation of the neighbouring trajectories. Having in view the geometrical construction of the system, we report a clear origin of chaoticity of the bouncing ball billiard. By this we claim that in case when the floor is made of arc of circles - in a certain interval of frequencies - a lower bound for the maximal Ljapunov can be evaluated by sem-ianalitical techniques.

nlin.CD↗