Towards the CSM-CFD modelling of membrane wings at high Reynolds numbers

Abstract

The field of Airborne Wind Energy is concerned with harvesting high-altitude wind power; the corresponding group in Delft, in particular, is investigating the suitability of a kite for this purpose. Due to the high complexity that such a system ensues, it is of interest to have a fundamental understanding of the critical aero-elastic modes of the structure in flight.
The aim of this project was to further extend on the existing research efforts in this area by coupling a high fidelity Reynolds-Averaged Navier-Stokes solver with an improved version of the existing structural solver framework and validate the model on simplified test cases using a partitioned approach. The developed methodology uses the open-source Computational Fluid Dynamics solver foam-extend with an adapter to the coupling library preCICE. For the structure model, an in-house Python code based on a nonlinear shell element formulation is utilised.
A literature survey revealed that while there exists an abundance of publications on strongly coupled Fluid-Structure Interaction problems, the majority of them are targeted at applications set in completely different flow regimes. Thus, the most difficult part of the project was to find appropriate validation data for membrane wings at high Reynolds numbers
Finally, the capabilities of the method have been successfully showcased on a classic FSI benchmark case, and a partial validation on benchmark cases at more realistic Reynolds numbers has been carried out as well. Hence going forward a full quantification of the accuracy of the method for its target application range is recommended.