Universal scaling parameter for a counter jet drag reduction technique in supersonic flows

2020 ◽  
Vol 32 (3) ◽  
pp. 036105 ◽  
Author(s):  
Siddesh Desai ◽  
Vishnu Prakash K ◽  
Vinayak Kulkarni ◽  
Hrishikesh Gadgil
Keyword(s):  
Drag Reduction ◽  
Supersonic Flows ◽  
Reduction Technique ◽  
Universal Scaling ◽  
Scaling Parameter

Universal scaling parameter in the coil-to-globule transition

1992 ◽  
Vol 25 (26) ◽  
pp. 7300-7305 ◽  
Author(s):  
Il Hyun Park ◽  
Jae Hoon Kim ◽  
Taihyun Chang
Keyword(s):  
Universal Scaling ◽  
Scaling Parameter

Influences of lateral jet location and its number on the drag reduction of a blunted body in supersonic flows

2020 ◽  
Vol 124 (1277) ◽  
pp. 1055-1069 ◽  
Author(s):  
M. Dong ◽  
J. Liao ◽  
Z. Du ◽  
W. Huang
Keyword(s):  
Drag Reduction ◽  
Drag Force ◽  
Blunt Body ◽  
Stokes Equations ◽  
Supersonic Flows ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Reduction Strategies ◽  
Promising Application ◽  
Force Reduction

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.

scholarly journals Aerodynamic drag reduction and flow control of Ahmed body with flaps

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771139 ◽  
Author(s):  
Jie Tian ◽  
Yingchao Zhang ◽  
Hui Zhu ◽  
Hongwei Xiao
Keyword(s):  
Drag Reduction ◽  
Flow Control ◽  
Parametric Analysis ◽  
Aerodynamic Drag ◽  
Pressure Coefficient ◽  
Reduction Technique ◽  
Longitudinal Vortex ◽  
Near Wake ◽  
Aerodynamic Drag Reduction ◽  
Coefficient Reduction

In this study, we attempted a novel drag reduction technique for 25° and 35° Ahmed models by experimenting with two types of flap structures, respectively, added to the slant edges of the two models. Different pairs of flaps were added at various angles compared to the slant for the sake of comparison. The study comprehensively analyzed the effects of the “big-type” and “small-type” flaps on the aerodynamic drag and near wake of an Ahmed model in a greater range of flap mounting angles. Parametric analysis results confirmed that large and small flaps are most efficient when configured on the 25° Ahmed model at specific angles; up to 21% pressure coefficient reduction was achieved for the 25° Ahmed model (flap configurations at slant side edge) and 6% for the 35° Ahmed model (flap configurations at both slant side and top edges). The velocity and pressure contours indicated that the key to drag reduction is to weaken (if not eliminate) the longitudinal vortex created at the side edges of the rear slant.

scholarly journals Parametric study on drag reduction with the combination of the upstream energy deposition and the opposing jet configuration in supersonic flows

2020 ◽  
Vol 171 ◽  
pp. 300-310 ◽  
Author(s):  
Shengjun Ju ◽  
Zhenxu Sun ◽  
Guowei Yang ◽  
Prasert Prapamonthon ◽  
Junyuan Zhang
Keyword(s):  
Drag Reduction ◽  
Parametric Study ◽  
Energy Deposition ◽  
Supersonic Flows

Applications of a Counterflow Drag Reduction Technique in High-Speed Systems

2002 ◽  
Vol 39 (4) ◽  
pp. 605-614 ◽  
Author(s):  
Eswar Josyula ◽  
Mark Pinney ◽  
William B. Blake
Keyword(s):  
Drag Reduction ◽  
High Speed ◽  
Reduction Technique

scholarly journals Low-Cost Base Drag Reduction Technique

2018 ◽  
Vol 7 (4) ◽  
pp. 428-432 ◽  
Author(s):  
Mohammed Asadullah ◽  
Sher Afghan Khan ◽  
Waqar Asrar ◽  
Sulaeman. E
Keyword(s):  
Drag Reduction ◽  
Low Cost ◽  
Reduction Technique ◽  
Base Drag

scholarly journals Boundary Layer Mixture Model for a Microbubble Drag Reduction Technique

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Jing-Fa Tsai ◽  
Chi-Chuan Chen
Keyword(s):  
Boundary Layer ◽  
Drag Reduction ◽  
Flat Plate ◽  
Mixture Model ◽  
Frictional Resistance ◽  
Reduction Technique ◽  
Measuring System ◽  
Water Tunnel ◽  
Towing Tank ◽  
Reduction Effect

The boundary mixture model is derived to predict the performance of the microbubble drag reduction technique for a flat plate. The flat plate with a porous material microbubble injecting system and resistance-measuring system are set up to measure the frictional resistance of the flat plate without and with injected microbubbles. The tests are conducted in a water tunnel and a towing tank. The test results show that the boundary mixture model predicts the drag reduction well for the flat plate when testing with injected microbubbles in the water tunnel. However, the boundary mixture model overestimates the drag reduction effect for the flat plate tested in the towing tank. The possible mechanism for the overestimation of drag reduction effect in the towing tank may be due to the different behaviors of microbubbles in the velocity gradient of boundary layer.

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