scholarly journals Aerodynamic Drag Reduction for a Generic Truck Using Geometrically Optimized Rear Cabin Bumps

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Abdellah Ait Moussa ◽  
Justin Fischer ◽  
Rohan Yadav
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Reduction ◽  
Aerodynamic Drag ◽  
Numerical Technique ◽  
Fuel Efficiency ◽  
Orthogonal Arrays ◽  
Promising Strategy ◽  
Vehicle Fuel Efficiency ◽  
Aerodynamic Drag Reduction

The continuous surge in gas prices has raised major concerns about vehicle fuel efficiency, and drag reduction devices offer a promising strategy. In this paper, we investigate the mechanisms by which geometrically optimized bumps, placed on the rear end of the cabin roof of a generic truck, reduce aerodynamic drag. The incorporation of these devices requires proper choices of the size, location, and overall geometry. In the following analysis we identify these factors using a novel methodology. The numerical technique combines automatic modeling of the add-ons, computational fluid dynamics and optimization using orthogonal arrays, and probabilistic restarts. Numerical results showed reduction in aerodynamic drag between 6% and 10%.

scholarly journals Variable cant angle winglets for improvement of aircraft flight performance

Meccanica ◽  
2020 ◽  
Vol 55 (10) ◽  
pp. 1917-1947
Author(s):  
J. E. Guerrero ◽  
M. Sanguineti ◽  
K. Wittkowski
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Reduction ◽  
Fuel Efficiency ◽  
Aerodynamic Performance ◽  
Flight Performance ◽  
Sweep Angle ◽  
Aircraft Flight ◽  
Induced Drag ◽  
Aircraft Performance

Abstract Traditional winglets are designed as fixed devices attached at the tips of the wings. The primary purpose of the winglets is to reduce the lift-induced drag, therefore improving aircraft performance and fuel efficiency. However, because winglets are fixed surfaces, they cannot be used to control lift-induced drag reductions or to obtain the largest lift-induced drag reductions at different flight conditions (take-off, climb, cruise, loitering, descent, approach, landing, and so on). In this work, we propose the use of variable cant angle winglets which could potentially allow aircraft to get the best all-around performance (in terms of lift-induced drag reduction), at different flight phases. By using computational fluid dynamics, we study the influence of the winglet cant angle and sweep angle on the performance of a benchmark wing at Mach numbers of 0.3 and 0.8395. The results obtained demonstrate that by adjusting the cant angle, the aerodynamic performance can be improved at different flight conditions.

scholarly journals Variable Cant Angle Winglets for Improvement of Aircraft Flight Performance

2019 ◽  
Author(s):  
Joel Guerrero ◽  
Kevin Wittkowski ◽  
Marco Sanguineti
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Reduction ◽  
Fuel Efficiency ◽  
Aerodynamic Performance ◽  
Flight Performance ◽  
Sweep Angle ◽  
Aircraft Flight ◽  
Induced Drag ◽  
Aircraft Performance

Traditional winglets are designed as fixed devices attached at the tips of the wings. The primary purpose of the winglets is to reduce the lift-induced drag, therefore improving aircraft performance and fuel efficiency. However, because winglets are fixed surfaces, they cannot be used to control lift-induced drag reductions or to obtain the largest lift-induced drag reductions at different flight conditions (take-off, climb, cruise, loitering, descent, approach, landing, and so on). In this work, we propose the use of variable cant angle winglets which could potentially allow aircraft to get the best all-around performance (in terms of lift-induced drag reduction), at different flight phases. By using computational fluid dynamics, we study the influence of the winglet cant angle and sweep angle on the performance of a benchmark wing at Mach numbers of 0.3 and 0.8395. The results obtained demonstrate that by adjusting the cant angle, the aerodynamic performance can be improved at different flight conditions.

Effect of Boat Tail Profile on Drag Coefficient of a Sedan Using CFD

2017 ◽  
Author(s):  
Salman Javed ◽  
Farhan Javed ◽  
Samsher
Keyword(s):  
Drag Reduction ◽  
High Speed ◽  
Aerodynamic Drag ◽  
Fuel Efficiency ◽  
Primary Objective ◽  
Optimum Shape ◽  
Passenger Cars ◽  
Ground Conditions ◽  
Catenary Curve ◽  
Aerodynamic Drag Reduction

An appendage is a boat tail which is installed at the rear section of the passenger car. An inflatable appendage has been developed to reduce the aerodynamic drag experienced by passenger cars. It can be inflated when driving under high-speed conditions and deflated while parking. In this study, an appendage is designed to maintain the streamlined rear body configuration and reduce flow separation. The profile of this aerodynamic device is based on several mathematical curves such as kappa curve, lame curve, catenary curve and aerofoil curve. Four types of boat tailing devices with different lengths and profiles were installed, and computational fluid dynamics (CFD) analysis was performed under moving ground conditions. The primary objective of this study is to find an optimum shape for the appendage and explain the aerodynamic drag reduction mechanism. Comparisons between the base model and modified models were made on the basis of the coefficient of drag, pressure contours, velocity contours, velocity streamlines and pressure distribution plot. It is shown that significant drag reduction can be obtained with the proposed aerodynamic device. Improvement in fuel efficiency varies based on the profile of add-on device. It is shown numerically that the aerodynamic performance is improved by 18.8% compared to the base model. As a result, the fuel consumption of the modified sedan reduces by 4.5%.

Reduced Aerodynamic Drag for Truck-Trailer Configurations Using Parametrized CFD Studies

2012 ◽  
Author(s):  
Srdan Pavlović ◽  
Magnus Andersson ◽  
Jonas Lantz ◽  
Matts Karlsson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Reduction ◽  
Conceptual Design ◽  
Fuel Economy ◽  
Aerodynamic Drag ◽  
Foreseeable Future ◽  
Heavy Duty ◽  
Computational Fluid Dynamics Cfd

In the presented work, two studies using Computational Fluid Dynamics (CFD) have been conducted on a generic truck-like model with and without a trailer unit at a speed of 80 km/h. The purpose is to evaluate drag reduction possibilities using externally fitted devices. A first study deals with a flap placed at the back of a rigid truck and inclined at seven different angles with two lengths. Results show that it is possible to decrease drag by 4%. In a second study, the flap has been fitted on the tractor and trailer units of a truck-trailer combination. Four settings were surveyed for this investigation, one of which proved to decrease drag by up to 15%. A last configuration where the gap between the units has been closed has also been evaluated. This configuration offers a 15% decrease in drag. Adding a flap to the closed gap configuration decreases drag by 18%. New means of reducing aerodynamic drag of heavy-duty (HD) vehicles will be important in the foreseeable future in order to improve the fuel economy. The possibilities of reducing drag are prevalent using conceptual design.

A Study of an Active Rear Diffuser Device for Aerodynamic Drag Reduction of Automobiles

2012 ◽  
Author(s):  
Seung-On Kang ◽  
Jun-Ho Cho ◽  
Sang-Ook Jun ◽  
Hoon-Il Park ◽  
Ki-Sun Song ◽  
...  
Keyword(s):  
Drag Reduction ◽  
Aerodynamic Drag ◽  
Aerodynamic Drag Reduction

Computational Fluid Dynamics (CFD) Simulation of Drag Reduction by Riblets on Automobile

2010 ◽  
Author(s):  
N. N. N. Ghazali ◽  
Y. H. Yau ◽  
A. Badarudin ◽  
Y. C. Lim ◽  
Jane W. Z. Lu ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Reduction ◽  
Cfd Simulation ◽  
Computational Fluid Dynamics Cfd

scholarly journals Investigation of Influence of Adjustments in Cyclist Arm Position on Aerodynamic Drag Using Computational Fluid Dynamics

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 159
Author(s):  
Knut Erik Teigen Giljarhus ◽  
Daniel Årrestad Stave ◽  
Luca Oggiano
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Aerodynamic Drag ◽  
Time Trial ◽  
Elbow Extension ◽  
Cfd Simulations ◽  
Arm Position ◽  
Sport Activities ◽  
The Face ◽  
Computational Fluid Dynamics Cfd

In professional cycling, even small adjustments in position could mean that valuable seconds are gained over the course of a time-trial race. This study investigates the influence of arm position on the aerodynamic drag of a cyclist. Based on a 3D scanned model of a professional cyclist, 64 alternate positions are generated. The parameters that are investigated are the distance between elbows, elbow extension, and distance between hands. Computational fluid dynamics (CFD) simulations of all positions are performed, and a regression model is built from the results. The results indicate that the optimal posture is achieved for a minimum in all investigated parameters, which means that the hands and elbows should be kept together with hands up towards the face. Furthermore, elbow extension seems to be the most crucial parameter, followed by the distance between elbows, and then by the distance between the hands. The presented methodology can be applied to study other parameters relevant to cycling aerodynamics or be applied to other sport activities as well.

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