Backward erosion piping: Initiation and progression

Backward erosion piping is an internal erosion mechanism during which shallow pipes are formed in the direction opposite to the flow underneath water-retaining structures as a result of the gradual removal of sandy material by the action of water. It is an important failure mechanism in both dikes and dams where sandy layers are covered by a...

Artificial boundary conditions for nonlinear discrete problems in gas dynamics

The previous theory of artificial boundary conditions in gas dynamics has been elaborated mostly for the Euler equations. However, in practice, such boundary treatments are applied to discrete methods to solution of gasdynamic problems. In this study, based on exact nonreflecting boundary conditions for the 1D linearized Euler equations, we...

Physical and numerical aspects of aeroelastic simulations

A system for computer aided analysis and design of multi-element airfoils

A program system has been developed as a tool for interactive analysis and design of multi-element airfoils in incompressible viscous flow. A global description of the system is given. It involves the application of three computational methods, one for the analysis of viscous flow and one for the analysis of inviscid flow around multi-element...

Application of a constrained inverse method in the aerodynamic design of a low speed wing-slat configuration

At NLR a system for the computational design on multi-element airfoil has been developed. This design system solves the inverse aerodynamic problem in an approximate way. A priori specified aerodynamic requirements (surface pressure distribution) and geometric requirements are minimized in a least-squares way, introducing weight factors to...

A quasi-simultaneous calculation method for strongly interacting viscous flow around an infinite swept wing

An outline is presented of a new code, called VISIAN, for the analysis of aerodynamic flows with strong viscous-inviscid interaction. The code is based on the recently developed quasi-simultsuieous method for the calculation of strongly interacting boundary layers. The feasibility of this method has already been demonstrated liy means of a...

Comparison of boundary layer calculations for the root section of a wing

At the workshop nine participants presented the results of their calculations for a practical test case. The test case deals with the 3D turbulent boundary layer development, including separation, on the root section of a swept wing. The employed calculation methods comprise 3D integral methods as well as field methods. A short description of...

A calculation method of the viscous flow around multi-component airfoils

The viscous flow around multi-component airfoils has been calculated by solving incompressible potential flow and boxindary layer problems iteratively. The potential flow problem is solved by a revised version of the 2D NLR panel method. A model transport equation of turbulent stress is employed to calculate the turbulent boundary layer. The...