J.W. van der Burg

Development and applications of a 3D compressible Navier-Stokes solver

As a part of the Dutch ISNaS project our group and NLR jointly develop a flow solver for compressible, turbulent flow. This flow solver is especially aimed at applications on the industrial level: the nm]ti-element airfoil and wing/body combination, both at transonic flow conditions. The flow solver is based on the Reynolds-averaged Navier-Stokes equations, in which presently the algebraic Baldwin-Lomax turbulence model is adopted. In reference [1] the first results, for laminar and turbulent flow around ~ single airfoil and over a finite flat plate have been shown. In the present paper recent developments in the solver are discussed. In section 2 the numerical method used in the ISNaS solver is briefly described. Section 3 discusses the role of the numerical, or artificial dissipation in relation to the physical dissipation. In section 4 numerical aspects of the extension of the monoblock solver to a multiblock solver are described. The numerical method used in the ISNaS solver serves as a basis for many CFD programs used in our group. These programs are not only intended for the tw o applications mentioned above, but also for more fundamental studies of turbulence (with the help of large eddy simulation (LES) and direct numerical simulation (DNS)) and for the simulation of viscous water waves. In section 5 of this paper the use of the numerical method in large eddy simulation is discussed.

Multigrid and Runge-Kutta time stepping applied to the uniformly non-oscillatory scheme for conservation laws

It is known that Hartens uniformly non-oscillatory scheme is a second-order accurate scheme for discretizing coservation laws. In this paper a multigrid technique and Runge-Kutta time stepping with frozen dissipation is applied to Hartens scheme in order to obtain the steady-state solution. It is shown that these techniques applied to Hartens scheme lead to a better convergence to the steady-state solution of a first-order conservation law than applied to Jamesons scheme.