Along with the development of large aircraft, such as the Airbus A3XX, aeroelasticity and its consideration in the design process becomes ever more important. As an example that can be given serves the flutter of big, flexible wings. The flutter-onset occurs early and has thus to be predicted accurately.

Since experimental investigations are expensive and computer resources get cheaper reduction in experimental effort due to efficient and accurate computational simulations might lead to crucial competitive advantages. Under these viewpoints the capabilities of the CFD-software developed at HFI is enhanced to CSM (Computational Structure Mechanics) so that both problems can be solved for simultaneously. In the first step this work is confined to 2D-phenomena in the context of the BRITE-EURAM research project UNSI where an iterative coupling using the same method for both problems is aimed at.


Fluid- and structure mechanics are governed by the same conservation-equations for mass, moment and energy, but in practice the numerical schemes mostly applied are fundamentally different. Our basic approach is to use numerical methods for simultaneous solution of aerodynamic and structure mechanic problems based on the Finite Volume Method (FVM) for block-structured grids with non-matching block-interfaces. Moving and deforming grids are implemented obeying the Space Conservation Law (SCL). It was already shown that the Finite Volume Method can be used to capture elasticity-problems [1,2,3].

The CFD-software is an implicit procedure of second order accuracy. Complex goemetries and local mesh refinements can be handled by semi-structured grids on the basis of general curvilinear coordinates. The cartesian velocity components as well as all further variables are stored in the control-volume centers. Diffusive terms are approximated applying central difference schemes whereas convective terms are approximated by monotonous, limited functions of higher order. The governing equations are solved sequentially, where a pressure-correction algorithm of the SIMPLE type is carried out to ensure mass conservation.


The first results of coupled computations have been obtained during UNSI for a flexible but inextensible sail [4], which has been modelled as a chain to compute the sail shape.

Current Research Projects

Within the DFG-Project (TH 288/29-2) investigationens about the dead-space-ventilation in animal models with acute lung injurie are carried out.
Protektive Beatmung Quantitative analysis of dead-space-ventilation in animal models with acute lung injurie.

In a french-german collaboration between TU Berlin and Aix-Marseille Université, the aerodynamics of flapping insect flight is investigated
Numerical investigation of insect flight


[1] Bunge, U:  Die Behandlung der Strukturmechanik mittels der FV-Methode, Internal report 01/99, Hermann-Föttinger Institut, TU Berlin, April 1999, only available in German
[2] Demirdzic, I.; Muzaferija, S.:  Finite Volume Method for Stress Analysis in Complex Domains, Int. J. f. Num. M. in Eng., Vol. 37, 1994
[3] Demirdzic, I.; Muzaferija, S.:  Numerical Method for Coupled Fluid Flow, Heat Transfer and Stress Analysis using Unstructured Moving Meshes with Cells of Arbitrary Topology, Comput. Methods Appl. Mech. Engrg., Vol. 125, 1995, pp. 235-255
[4] Bunge, U.; Rung, T.; Thiele, F.:  A two-dimensional sail in turbulent flow, Fluid Strucrure Interaction, Chakrabarti, S. K.; Brebbia, C. A. (Eds.), pp. 245-254, Series: Advances in Fluid Mechanics, Vol. 30, WIT Press, Southampton, Boston, 2001, ISBN 1-85312-881-3, presented by Bunge, U. on Fluid Strucrure Interaction 2001 in Chalkidiki, Greece, September 2001


Last modified: Thu Nov 1 15:34:36 CET 2001