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High-order detached-eddy simulation of external aerodynamics over an SAE notchback model

  • A. Islam (a1) and B. Thornber (a1)

Abstract

This research explores the modification and implementation of a Detached-Eddy Simulation (DES) in a high-order compressible solver and its application to automotive aerodynamics. This was conducted on a 20° SAE Reference Notchback Model with a Reynolds number of 2.23 × 105. This DES algorithm implemented within FLAMENCO, which is finite-volume research code operating over multi-block meshes, was used for all the simulations. The primary objectives were to capture unsteady flow features, separated coherent structures and also relax the meshing requirements to improve accessibility to turbulence-resolving methods for realistic configurations. This also aims to better understand the separated flow physics, especially around the base surfaces of the car. Simulations for three mesh refinement levels were compared to wind-tunnel measurements. Even on relatively coarse meshes (~7 m cells) for DES, time-averaged C p was obtained with maximum errors of <8%.

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This is an adaptation of a paper first presented at the 2015 Asia-Pacific International Symposium on Aerospace Technology in Cairns, Australia

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1. Sagaut, P. and Deck, S. A framework for aircraft conceptual design and environmental performance studies, Philosophical Transactions of the Royal Society of London, 2009, 367, pp 28492860, doi: 10.1098/rsta.2008.0269.
2. Spalart, P.R., Deck, S., Shur, M.L. and Squires, K.D. A new version of detached-eddy simulation, resistant to ambiguous grid densities, Theoretical Computational Fluid Dynamics, 2006, 20, (3), pp 181195.
3. Islam, M., Decker, F., de Villiers, E., Jackson, A., Gines, J., Grahs, T., Gitt-Gehrke, A. and Comas i Font, J. Application of the detached-Eddy simulation for automotive aerodynamics development, Society of automotive engineers, Tech Rep, SAE 2009-01-0333, 2009, doi: 10.4271/2009-01-0333.
4. Chapman, D.R. Computational aerodynamics development and outlook, AIAA J, 1979, 17, (1293).
5. Choi, H. and Moin, P. Grid-point requirements for large eddy simulation: Chapman’s estimates revisited, Physics of Fluids, 2012, 24, (011702), pp 15.
6. Guilmineau, E., Deng, G. and Wackers, J. Numerical simulation with a DES approach for automotive flows, J of Fluids and Structures, 2011, 27, pp 807816.
7. Wood, D., Passmore, M. and Perry, A. Loughborough University Institutional Repository, Loughborough University, 2017. [Online]. Available: https://dspace.lboro.ac.uk/2134/13886. [Accessed: 20-Feb-2017].
8. Ashton, N. and Revell, A. Key factors in the use of DDES for the flow around a simplified car, Int J of Heat and Fluid Flow, 2015, 54, pp 236249.
9. Le Good, G. and Garry, K.P. On the use of reference models in automotive aerodynamics, Society of Automotive Engineers, Tech Rep, SAE 2004-01-1308, 2004, doi: 10.4271/2004-01-1308.
10. Wood, D., Passmore, M. and Perry, A. Experimental data for the validation of numerical methods - SAE reference notchback model, SAE Int J of Passenger Cars - Mech Systems, 2014, 7, (1), pp 145154.
11. Shanmuganathan, S., Youngs, D.L., Griffond, J., Thornber, B. and Williams, R.J.R. Accuracy of high-order density-based compressible methods in low Mach vortical flows, Int J of Numerical Methods in Fluids, 2014, 74, pp 355358.
12. Garcia-Uceda Juarez, A., Raimo, A., Shapiro, E. and Thornber, B. Steady flow computations using a low mach fully compressible scheme, AIAA J, 2014, 52, (11), pp 25592575.
13. Islam, A. and Thornber, B. Development and application of a novel RANS and implicit LES hybrid turbulence model for automotive aerodynamics, SAE Technical Paper 2016-01-1608, 2016, doi: 10.4271/2016-01-1608.
14. Islam, A. and Thornber, B. A hybrid RANS-implicit LES method for external aerodynamics, Proceedings of the 19th Australasian Fluid Mechanics Conference, 2014, RMIT Australia. [Online]. Available: http://people.eng.unimelb.edu.au/imarusic/proceedings/19/54.pdf. [Accessed: 20-Dec-2016].
15. Thornber, B. and Zhou, Y. Energy transfer in the Richtmyer-Meshkov instability, Physical Review E, 86, (056302), 2012.
16. Zhou, Y. and Thornber, B. A comparison of three approaches to compute the effective Reynolds number of the implicit Large-Eddy simulations, J Fluids Engineering, Transactions of the ASME, 2016, 138, (7).
17. Leveque, R.J. Finite Volume Methods for Hyperbolic Problems, Cambridge Texts in Applied Mathematics, Cambridge University Press, London, 2002.
18. Drikakis, D., Hahn, M., Mosedale, A. and Thornber, B. Large eddy Simulation using high-resolution and high-order methods, Philosophical Transactions of the Royal Soc of London, 2009, 367, pp 29852997.
19. Thornber, B., Mosedale, D., Drikakis, D. and Williams, R.J.R. An improved reconstruction method for compressible flows with low Mach number features, J Computational Physics, 2008, 227, pp 48734894.
20. Thornber, B., Drikakis, D., Williams, R.J.R. and Youngs, D. On entropy generation and dissipation of kinetic energy in high-resolution shock-capturing schemes, J Computational Physics, 2008, 10, pp 48534872.
21. Thornber, B. and Drikakis, D. Implicit Large-Eddy simulation of a deep cavity using high-resolution methods, AIAA J, 2008, 46, (10), pp 26342645.
22. Thornber, B., Starr, M. and Drikakis, D. Implicit Large Eddy simulation of ship airwakes, The Aeronautical J, 2010, 114, pp 715736.
23. Axelsson, N., Ramnefors, M. and Gustafsson, R. Accuracy in computational aerodynamics part I: Stagnation pressure, Society of Automotive Engineers, SAE Technical Report 980037, International Congress and Exposition, 23–26 February 1998, doi: 10.4271/980037.
24. Nader, A., Islam, A. and Thornber, B. A comparative aerodynamic investigation of a 20° SAE notchback model, Applied Mech and Materials, 2015, 846, pp 7984.
25. Carr, G.W. and Stapleford, W.R. Blockage effects in automotive wind-tunnel testing, SAE Technical Paper Series 860093, 1985, doi: 10.4271/860093.
26. Rana, Z., Thornber, B. and Drikakis, D. On the importance of generating accurate turbulent boundary conditions for unsteady simulations, J Turbulence, 2011, 12, (35), pp 139.
27. Toro, E., Spruce, M. and Speares, W. Restoration of the contact surface in the HLLC-Riemann solver, Shock Waves, 1994, 4, (1), pp 2534.
28. Godunov, S.K. A finite-difference method for the computation of discontinuous solutions of the equations of fluid dynamics, Matematicheskiĭ Sbornik. Novaya Seriya, 1959, 47, (89), pp 271306.
29. Kim, K. and Kim, C. Accurate, efficient and monotonic numerical methods for multi-dimensional compressible flows part ii. Multi-dimensional limiting process, J Computational Physics, 2005, 208, pp 570615.
30. Harten, A., Lax, P. and van Leer, B. On upstream differencing and Godunov-type schemes for hyperbolic conservation laws, SIAM Review, 1983, 25, (1), pp 3561.
31. Thornber, B. and Drikakis, D. Numerical dissipation of upwind schemes in low Mach flow, Int J for Numerical Methods in Fluids, 2007, 56, (8), pp 15351541.
32. Spiteri, R.J. and Ruuth, S.J. A class of optimal strong-stability preserving time discretisation methods. SIAM J of Numerical Analysis, 2002, 40, (2), pp 469491.
33. Burgess, N.K. and Mavripalis, D. Robust computation of turbulent flows using a discontinuous Galerkin method, 50th AIAA Aerospace Sciences Meeting and Exhibit, 9–12 January 2012, Nashville, Tennessee, US, doi: 10.2514/6.2012-457.
34. Gaylard, A., Howell, J. and Garry, K. Observation of flow asymmetry over the rear of notchback vehicles, SAE Technical Paper, 2007-01-0900, 2007, doi: 10.4271/2007-01-0900.
35. Hunt, J.C.R., Wray, A. and Moin, P. Eddies, stream, and convergence zones in turbulent flows, Center for Turbulence Research, Research Report CTR-S88. [Online]. Available: https://web.stanford.edu/group/ctr/Summer/201306111537.pdf. [Accessed: 20-Dec-2016].

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High-order detached-eddy simulation of external aerodynamics over an SAE notchback model

  • A. Islam (a1) and B. Thornber (a1)

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