Tractor-Trailer Drag Reduction Strategies Determined from CFD

Author(s):  
Fu-Hung Hsu ◽  
Roger Davis
2020 ◽  
Vol 124 (1277) ◽  
pp. 1055-1069 ◽  
Author(s):  
M. Dong ◽  
J. Liao ◽  
Z. Du ◽  
W. Huang

ABSTRACTThe analysis of the aerodynamic environment of the re-entry vehicle attaches great importance to the design of the novel drag reduction strategies, and the combinational spike and jet concept has shown promising application for the drag reduction in supersonic flows. In this paper, the drag force reduction mechanism induced by the combinational spike and lateral jet concept with the freestream Mach number being 5.9332 has been investigated numerically by means of the two-dimensional axisymmetric Navier-Stokes equations coupled with the shear stress transport (SST) k-ω turbulence model, and the effects of the lateral jet location and its number on the drag reduction of the blunt body have been evaluated. The obtained results show that the drag force of the blunt body can be reduced more profoundly when employing the dual lateral jets, and its maximum percentage is 38.81%, with the locations of the first and second lateral jets arranged suitably. The interaction between the leading shock wave and the first lateral jet has a great impact on the drag force reduction. The drag force reduction is more evident when the interaction is stronger. Due to the inclusion of the lateral jet, the pressure intensity at the reattachment point of the blunt body decreases sharply, as well as the temperature near the walls of the spike and the blunt body, and this implies that the multi-lateral jet is beneficial for the drag reduction.


2008 ◽  
Vol 608 ◽  
pp. 161-196 ◽  
Author(s):  
MARK PASTOOR ◽  
LARS HENNING ◽  
BERND R. NOACK ◽  
RUDIBERT KING ◽  
GILEAD TADMOR

Drag reduction strategies for the turbulent flow around a D-shaped body are examined experimentally and theoretically. A reduced-order vortex model describes the interaction between the shear layer and wake dynamics and guides a path to an efficient feedback control design. The derived feedback controller desynchronizes shear-layer and wake dynamics, thus postponing vortex formation. This actuation is tested in a wind tunnel. The Reynolds number based on the height of the body ranges from 23000 to 70000. We achieve a 40% increase in base pressure associated with a 15% drag reduction employing zero-net-mass-flux actuation. Our controller outperforms other approaches based on open-loop forcing and extremum-seeking feedback strategies in terms of drag reduction, adaptivity, and the required actuation energy.


2010 ◽  
Author(s):  
Michael T. Sliter ◽  
Scott A. Withrow ◽  
Michelle H. Balzer ◽  
Michelle H. Brodke ◽  
Jennifer Z. Gillespie ◽  
...  
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