A Joint European Initiative to Develop Hybrid Grid Based CFD-Technology for Inviscid and Viscous Flow Computations Applicable to Geometrically Complex Aircraft Configurations

A joint European initiative to develop hybrid grid based CFD-technology with a short problem-turnaround time applicable to complex aircraft configurations has been undertaken. In the context of the Brite-Euram fourth framework programme two projects have been executed, namely FASTFLO I (1996-1998) and FASTFLO II (1998-2000). The practical outcome of the joint development has been CFD technology with inviscid (FASTFLO I) and viscous (FASTFLO II) flow modelling for complex aircraft configurations (see figure 1 for an example). The resulting CFD technology is based on the hybrid grid approach (Ref. 7); this approach combines prismatic grid generation in a layer near aerodynamic surfaces with tetralhedral grid generation in the remainder of the flow domain. It has been concluded that the hybrid grid based CFD technology (both viscous, and inviscid flow models) meets the following two industrial requirements: 1. The CFD problem-turnaround time is within the order of a week for geometrically complex aircraft configurations and, 2. The CFD technology is able to provide a sufficient accuracy of the aerodynamic entities (like pressure, lift, drag and moments)

Development of numerical algorithms for end-user applications in aerospace

In this paper, a cross-section of numerical algorithm development at NLR for end-user applications in aerospace is presented. Aerospace is characterized by high safety requirements and standards, complex development programs and operational processes, and challenging multi-physics phenomena. An example is the certification or qualification of civil and military aircraft, helicopters, Unmanned (Combat) Aerial Vehicles (UCAV), or Expendable Launch Vehicles (ELV). This application requires numerical algorithms that have a high level of physical fidelity, a high level of accuracy, short total turn-around times, and low cost. Three applications driving numerical algorithm development at NLR are presented: the simulation of nozzle buffet loads, for qualified space launchers, the simulation of non-linear flutter properties, for qualified fighter configurations, and the simulation of blade-vortex interaction, for the development of environmentally friendly helicopters