Due to the extreme conditions required to produce energy by nuclear fusion in tokamaks, simulating the plasma behavior is an important but challenging task. We focus on the edge part of the plasma, where fluid approaches are probably the best suited, and our approach relies on the Braginskii ion-electron model. Assuming that the electric field is electrostatic, this yields a set of 10 strongly ...

The flow problem presented in the paper is boundary-layer flow of nanofluids over a moving surface in the presence of thermal radiation, viscous dissipation and chemical reaction. The plate is assumed to move in the same or opposite direction to the free stream which depends on the sign of the velocity parameter. The partial differential equations appearing in the governing equations are transf...

For many flow problems modeled by Large Eddy Simulation (LES), the computational meshes are such that a large number of the elements would allow for explicit timestepping, but the CFL-condition is highly limited by the smaller stretched elements in the boundary layers. We propose an implicit-explicit time-integration scheme that uses an implicit solver only for the smaller portion of the domain...

Um mecanismo explícito para a reação da metacroleína (MTA) com radicais OH, numa mistura NOx ar, foi simulado resolvendo as equações diferenciais ordinárias usando o método RungeKutta-4-semi-implícito. Os resultados simulados são consistentes com os dados experimentais publicados e o modelo explica as principais vias de reação para a oxidação da MTA com radicais OH na presença de NOx ar. Usando...

We consider the numerical solution of systems of semi-explicit index 2 differential-algebraic equations (DAEs) by methods based on RungeKutta (RK) coefficients. For nonstiffly accurate RK coefficients, such as Gauss and Radau IA coefficients, the standard application of implicit RK methods is generally not superconvergent. To reestablish superconvergence projected RK methods and partitioned RK ...

In this paper the steady laminar magneto hydrodynamic (MHD) mixed convection boundary layer flow towards a vertical stretching sheet with variable fluid viscosity, radiation and in the presence of Dufour’s effect have been investigated. The governing partial differential equations are transformed into set of ordinary differential equations using similarity transformation, and then these equatio...

In this paper, we present a class of explicit numerical methods for stiff Itô stochastic differential equations (SDEs). These methods are as simple to program and to use as the well-known Euler-Maruyama method, but much more efficient for stiff SDEs. For such problems, it is well known that standard explicit methods face step-size reduction. While semi-implicit methods can avoid these problems ...

This work is an extension of our previous paper [3], in which we have started introducing new C software for autonomous ordinary differential equation initial-value problems y′ = f(y), y ∈ R, y(x0) = y0, x0 ∈ R, y0 ∈ R, which implements new Runge-Kutta methods [1], [2]. The novel feature of this approach is the replacement of evaluations of f by approximations or evaluations of fy. The advantag...