Abstract
The results of several investigations aimed at assessing the performance of contoured transverse grooves as a method to delay flow separation are described. The physical mechanism at the basis of this passive technique is the local relaxation of the no-slip boundary condition, with a consequent reduction of the viscous losses and an increase of the downstream near-wall momentum. Numerical simulations and experiments showed that the application of one groove transverse to the flow direction may delay boundary layer separation both in laminar and turbulent conditions. As a consequence, significant increases of the pressure recovery in plane diffusers and decreases of the drag of boat-tailed axisymmetric and two-dimensional bluff bodies were obtained. It is shown that robust configurations may be devised provided the shape and dimension of the grooves are suitably chosen in order to assure the formation of steady and stable local flow recirculations.
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References
Gad-el-Hak M (2000) Flow control: passive, active, and reactive flow management. Cambridge University Press, Cambridge
Demartino C, Ricciardelli F (2017) Aerodynamics of nominally circular cylinders: a review of experimental results for civil engineering applications. Eng Struct 137:76–114
Buresti G, Tondi D (2007) Stepped boat-tails: a proposal for the control of the aerodynamic loads on bluff bodies. In: Atti del Dipartimento di Ingegneria Aerospaziale, ADIA 2007-7, ETS Editrice, Pisa
Ringleb F (1961) Separation control by trapped vortices. In: Lachmann GV (ed) Boundary layer and flow control, vol 1. Pergamon Press, Oxford, pp 265–294
Iollo A, Zannetti L (2001) Trapped vortex optimal control by suction and blowing at the wall. Eur J Mech (B/Fluids) 20:724
Rossiter JE (1964) Wind-tunnel experiments on the flow over rectangular cavities at subsonic and transonic speeds. Aeronautical Research Council, R & M, No. 3438 (1964)
Rockwell D, Naudascher E (1978) Review - self-sustaining oscillations of flow past cavities. J Fluid Eng 100:152–165
Mariotti A, Grozescu AN, Buresti G, Salvetti MV (2013) Separation control and efficiency improvement in a 2D diffuser by means of contoured cavities. Eur J Mech B Fluid 41:138–149
Mariotti A, Buresti G, Salvetti MV (2014) Control of the turbulent flow in a plane diffuser through optimized contoured cavities. Eur J Mech B Fluid 48:254–265
Mariotti A, Buresti G, Salvetti MV (2015) Use of multiple local recirculations to increase the efficiency in diffusers. Eur J Mech B Fluid 50:27–37
Mariotti A, Buresti G, Gaggini G, Salvetti MV (2017) Separation control and drag reduction for boat-tailed axisymmetric bodies through contoured transverse grooves. J Fluid Mech 832:514–549
Mariotti A, Buresti G, Salvetti MV (2019) Separation delay through contoured transverse grooves on a 2D boat-tailed bluff body: effects on drag reduction and wake flow features. Eur J Mech B Fluid 74:351–362
Maull DJ, Hoole BJ (1967) The effect of boat-tailing on the flow round a two-dimensional blunt-based aerofoil at zero incidence. J R Aeronaut Soc 71:854–858
Mair WA (1969) Reduction of base drag by boat-tailed afterbodies in low-speed flow. Aeronaut Q 20:307–320
Buice CU, Eaton JK (2000) Experimental investigation of flow through an asymmetric plane diffuser. Trans ASME J Fluids Eng 122:433–435
Camarri S, Salvetti MV, Koobus B, Dervieux A (2004) A low-diffusion MUSCL scheme for LES on unstructured grids. Comput Fluids 33:1101–1129
Mariotti A, Buresti G, Salvetti MV (2015) Connection between base drag, separating boundary layer characteristics and wake mean recirculation length of an axisymmetric blunt-based body. J Fluid Struct 55:191–203
Mariotti A, Buresti G (2013) Experimental investigation on the influence of boundary layer thickness on the base pressure and near-wake flow features of an axisymmetric blunt-based body. Exp Fluids 54:1612
Mariotti A (2018) Axisymmetric bodies with fixed and free separation: base-pressure and near-wake fluctuations. J Wind Eng Ind Aerodyn 176:21–31
Jeong J, Hussain F (1995) On the identification of a vortex. J Fluid Mech 285:69–94
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Mariotti, A., Buresti, G., Salvetti, M.V. (2019). Flow Separation Delay and Drag Reduction Through Contoured Transverse Grooves. In: Ricciardelli, F., Avossa, A. (eds) Proceedings of the XV Conference of the Italian Association for Wind Engineering. IN VENTO 2018. Lecture Notes in Civil Engineering, vol 27. Springer, Cham. https://doi.org/10.1007/978-3-030-12815-9_37
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DOI: https://doi.org/10.1007/978-3-030-12815-9_37
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