Analysis of the Active and Passive Drag Reduction Strategies Behind a Square Back Ground Vehicle

2015 ◽  
pp. 363-376
Author(s):  
Charles-Henri Bruneau ◽  
Emmanuel Creusé ◽  
Delphine Depeyras ◽  
Patrick Gilliéron ◽  
Iraj Mortazavi
Keyword(s):  
Drag Reduction ◽  
Ground Vehicle ◽  
Reduction Strategies ◽  
Back Ground

Drag reduction on a flat-back ground vehicle with active flow control

2015 ◽  
Vol 145 ◽  
pp. 292-303 ◽  
Author(s):  
Jonathan McNally ◽  
Erik Fernandez ◽  
Gregory Robertson ◽  
Rajan Kumar ◽  
Kunihiko Taira ◽  
...  
Keyword(s):  
Drag Reduction ◽  
Flow Control ◽  
Active Flow Control ◽  
Ground Vehicle ◽  
Back Ground ◽  
Flat Back ◽  
Active Flow

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.

Numerical study of flow control strategies for a simplified square back ground vehicle

2017 ◽  
Vol 49 (3) ◽  
pp. 035502 ◽  
Author(s):  
Yoann Eulalie ◽  
Philippe Gilotte ◽  
Iraj Mortazavi
Keyword(s):  
Flow Control ◽  
Numerical Study ◽  
Control Strategies ◽  
Ground Vehicle ◽  
Back Ground

scholarly journals Quantitative Analysis of Drag Reduction Methods for Blunt Shaped Automobiles

2020 ◽  
Vol 10 (12) ◽  
pp. 4313 ◽  
Author(s):  
Ferenc Szodrai
Keyword(s):  
Quantitative Analysis ◽  
Drag Reduction ◽  
Web Of Science ◽  
Numerical Models ◽  
Digital Publishing ◽  
Ground Vehicles ◽  
Research Papers ◽  
Ground Vehicle ◽  
Wind Tunnel Measurements ◽  
Reduction Methods

In fluid mechanics, drag related problems aim to reduce fuel consumption. This paper is intended to provide guidance for drag reduction applications on cars. The review covers papers from the beginning of 2000 to April 2020 related to drag reduction research for ground vehicles. Research papers were collected from the library of Science Direct, Web of Science, and Multidisciplinary Digital Publishing Institute (MDPI). Achieved drag reductions of each research paper was collected and evaluated. The assessed research papers attained their results by wind tunnel measurements or calculating validated numerical models. The study mainly focuses on hatchback and notchback shaped ground vehicle drag reduction methods, such as active and passive systems. Quantitative analysis was made for the drag reduction methods where relative and absolute drag changes were used for evaluations.

Drag Reduction on the 25-deg Ahmed Model Using Fluidic Oscillators

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Matthew Metka ◽  
James W. Gregory
Keyword(s):  
Drag Reduction ◽  
Moving Objects ◽  
Ground Vehicle ◽  
Flow Energy ◽  
Structure Changes ◽  
Slant Surface ◽  
Oil Flow ◽  
Oscillating Jet ◽  
Oil Flow Visualization ◽  
Model Oil

Transportation of goods and people involves moving objects through air, which leads to a force opposing motion. This drag force can account for more than 60% of power consumed by a ground vehicle, such as a car or truck, at highway speeds. This paper studies drag reduction on the 25-deg Ahmed generic vehicle model with quasi-steady blowing at the roof–slant interface using a spanwise array of fluidic oscillators. A fluidic oscillator is a simple device that converts a steady pressure input into a spatially oscillating jet. Drag reduction near 7% was attributed to separation control on the rear slant surface. Particle image velocimetry (PIV) and pressure taps were used to characterize the flow structure changes behind the model. Oil flow visualization was used to understand the mechanism behind oscillator effectiveness. An energy analysis suggests that this method may be viable from a flow energy perspective.

Drag Reduction of a Simple Bluff Body by Changing the Rear End and Use the Ground Effect

2009 ◽  
Author(s):  
Jesper Marklund ◽  
Lennart Lofdahl
Keyword(s):  
Flow Field ◽  
Drag Reduction ◽  
Bluff Body ◽  
Ground Effect ◽  
Model Testing ◽  
Scale Model ◽  
Bluff Bodies ◽  
Ground Vehicle ◽  
University Of Technology ◽  
Force Reduction

The flow field around bluff bodies constitutes a classic area within fluid dynamics and has been the topic for much research through the years. However, in the use for road vehicles with the effect of the ground, the behavior is changed very much from more classical aviation usage. In this paper we are investigating the drag force reduction on a vehicle like simplified model with rear open diffuser when stationary ground simulation is considered. The objective with this work was to study the rear end of a bluff body and optimize it for drag with ground vehicle like boundaries. Here the testing contains two common body variants, square back, boat tailed/fastback in generic forms. Scale model testing combined with simulations is used to explain behavior and flow field. The model testing is performed in the L2 scale model wind tunnel at Chalmers University of Technology in Gothenburg, Sweden. Simulations are done with the commercial CFD code Fluent. A diffuser on a car is normally used to create down force but here it is tested to see if the energy in the flow can be used to optimize reduction of drag. One part of the study is to show the potential in optimizing the rear end underbody for drag, by varying the diffuser angle. The results show a potential in drag reduction by using a diffuser and varying effect depending on other rear end geometries.

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