TRANSONIC FLOW SIMULATION AROUND THE NASA CRM-NLF MODEL

Computational Fluid Dynamics plays an increasingly crucial role in the analysis, design, and support of aerospace aerodynamics applications [1]. This increased role brings continuous demands onto the development of new strategies for obtaining accurate results in a timely manner. Ultimately, design, analysis, and development activities lead to the necessity for further testing, verification, and validation of new developed tools [2].

In the present discussion, we highlight the capabilities of an OpenFOAM-based technology regarding high speed flow external aerodynamics applications. In particular, our focus is transonic flow simulation around the NASA Common Research Model with Natural Laminar Flow wing [3]. Spatial discretisation of the simulation domain is performed with helyxHexMesh, in order to leverage a dualized layer addition algorithm to increase layer coverage and layer quality on the NASA CRM body [4]. Flow simulations are obtained with a new High Speed Aerodynamic (HiSA) solver [5]. HiSA is an implicit finite volume density-based coupled solver developed within the HELYX framework in collaboration with Council of Scientific and Industrial Research, South Africa. Overall, the coupled solver enables a fast stable solution strategy to more readily perform an aerodynamic analysis over a wide range of Mach numbers. Figure 1 shows a typical velocity and pressure coefficient distributions on the surface of the CRM-NLF model. Further flow characteristics are analysed and compared with the existing experimental results to compare accuracy of the approach.

The simulation of transonic flows presents numerous challenges. Attendees will be presented with the challenges associated with meshing, solving, and analysing the NASA CRM-NFL model, and how these challenges were overcome. Lessons learned from this discussion can be applied to further development of tools and methodologies towards transonic flow simulation.

Figure 1: Planform view: velocity (left) and pressure coefficient (right) distributions on the surface of the CRM-NLF model

References

[1] P. R. Spalart, V. Venkatakrishnan, On the role and challenges of CFD in the aerospace industry, The Aeronautical Journal, Vol. 120, No. 1223, January 2016 [2] P. J. Roach, Verification of Codes and Calculations, AIAA Journal, Vol. 36, No. 5, May 1998 [3] M. N. Lynde, R. L. Campbell, S. A. Viken, Additional Findings from the Common Research Model Natural Laminar Flow Wind Tunnel Test, AIAA AVIATION 2019 Forum, 17-21 June 2019, Dallas, Texas [4] A. Jackson, P. Alexias and E. De Villiers, A dualised Hex-Mesh generator with cell quality optimisation, 11th OpenFOAM Workshop, 2016 Guimaraes, Portugal [5] J. A. Heyns, O. F. Oxtoby, A. Steenkamp, Modelling high-speed flow using a matrix-free coupled solver, 9th OpenFOAM Workshop, Croatia, 23-26 June, Apr. 2014.