The equations governing general relativistic, spherically symmetric, hydrodynamic accretion of polytropic fluid onto black holes are solved in Schwarzschild metric to investigate some of the transonic properties of the flow. Only stationary solutions are discussed. For such accretion, it has been shown that real physical sonic points may form even for flow with γ < 4

In this paper, an application of Homotopy Analysis Method (HAM) is applied to solve the equation governing the unsteady flow of a polytropic gas. Comparison are made between the Adomian decomposition method and homotopy analysis method. The results reveal that the homotopy analysis method is very effective and simp le and gives the exact solution. Classification 2000 MSC: 34K28 • 35G25 • 34K17

We present a useful analytic approximation to the solution of the Lane-Emden equation for infinite polytropic index the isothermal sphere. The optimized expression obtained for the density profile can be accurate to within 0.04% within 5 core-radii and to 0.1% within 10 core-radii.

We establish the global existence of L∞ solutions for a model of polytropic gas flow with diffusive entropy. The result is obtained by showing the convergence of a class of finite difference schemes, which includes the Lax– Friedrichs and Godunov schemes. Such convergence is achieved by proving the estimates required for the application of the compensated compactness theory.

We prove the finite time blow-up for C1 solutions to the EulerPoisson equations in R, n ≥ 1, with/without background density for initial data satisfying suitable conditions. We also find a sufficient condition for the initial data such that C3 solution breaks down in finite time for the compressible Euler equations for polytropic gas flows. AMS subject classification: 35Q35, 35B30

We compute multiprecision solutions of the Lane–Emden equation. This differential equation arises when introducing the well-known polytropic model into the equation of hydrostatic equilibrium for a nondistorted star. Since such multiprecision computations are time-consuming, we apply to this problem parallel programming techniques and thus the execution time of the computations is drastically r...

We prove the existence and nonlinear stability of steady states of the Vlasov-Poisson system in the stellar dynamics case. The steady states are obtained as minimizers of an energy-Casimir functional from which fact their dynamical stability is deduced. The analysis applies to some of the well-known polytropic steady states, but it also considerably extends the class of known steady states.

A novel approach for the investigation of reaction kinetics using a polytropic miniplant reactor featuring highly resolved fibre optic temperature measurement and FTIR gas phase analysis is presented methanol synthesis.

Solar-type stars generate spherical winds, which are pressure driven flows, that start subsonic, reach the sound speed at sonic point and transition to supersonic flows. The point, mathematically corresponds a singularity of system differential equations describing flow. In problem an isothermal wind, Parker solution provides exact analytical expression tuned appropriately so does not affect so...