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

Author(s):  
Srdan Pavlović ◽  
Magnus Andersson ◽  
Jonas Lantz ◽  
Matts Karlsson

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.


2010 ◽  
Author(s):  
N. N. N. Ghazali ◽  
Y. H. Yau ◽  
A. Badarudin ◽  
Y. C. Lim ◽  
Jane W. Z. Lu ◽  
...  


Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 159
Author(s):  
Knut Erik Teigen Giljarhus ◽  
Daniel Årrestad Stave ◽  
Luca Oggiano

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.



Author(s):  
Z. J. Wang

Most forecasts predict an annual airline traffic growth rate between 4.5 and 5% in the foreseeable future. To sustain that growth, the environmental impact of aircraft cannot be ignored. Future aircraft must have much better fuel economy, dramatically less greenhouse gas emissions and noise, in addition to better performance. Many technical breakthroughs must take place to achieve the aggressive environmental goals set up by governments in North America and Europe. One of these breakthroughs will be physics-based, highly accurate and efficient computational fluid dynamics and aeroacoustics tools capable of predicting complex flows over the entire flight envelope and through an aircraft engine, and computing aircraft noise. Some of these flows are dominated by unsteady vortices of disparate scales, often highly turbulent, and they call for higher-order methods. As these tools will be integral components of a multi-disciplinary optimization environment, they must be efficient to impact design. Ultimately, the accuracy, efficiency, robustness, scalability and geometric flexibility will determine which methods will be adopted in the design process. This article explores these aspects and identifies pacing items.



The development of electric vehicles demands minimizing aerodynamic drag in order to provide maximum range. The wheels contribute significantly to overall drag coefficient value because of flow separation from rims and wheel arches. In this paper various design parameters are investigated and their influence on vehicle drag coefficient is presented. The investigation has been done with the help of computational fluid dynamics (CFD) tools and with implementation of full vehicle setup with rotating wheels. The obtained results demonstrate changes in drag coefficient with respect to the change of design parameters.



2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Ramon Miralbes Buil ◽  
Luis Castejon Herrer

The aim of this article is the presentation of a series of aerodynamic improvements for semitrailer tankers, which reduce the aerodynamic resistance of these vehicles, and, consequently, result in a positive impact on fuel consumption, which is substantially reduced (up to 11%). To make the analysis the computational fluid dynamics (CFD) methodology, using FLUENT, has been used since it allows simulating some geometries and modifications of the geometry without making physical prototypes that considerably increase the time and the economical resources needed. Three improvements are studied: the aerodynamic front, the undercarriage skirt, and the final box adaptor. First they are studied in isolation, so that the independent contribution of each improvement can be appreciated, while helping in the selection of the most convenient one. With the aerodynamic front the drag coefficient has a reduction of 6.13%, with the underskirt 9.6%, and with the boat tail 7.72%. Finally, all the improvements are jointly examined, resulting in a decrease of up to 23% in aerodynamic drag coefficient.



2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Abdellah Ait Moussa ◽  
Justin Fischer ◽  
Rohan Yadav

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%.



2021 ◽  
Vol 11 (7) ◽  
pp. 3148
Author(s):  
Guillermo Puelles Magán ◽  
Wouter Terra ◽  
Andrea Sciacchitano

In this work, we investigate the flow field around speed skating helmets and their associated aerodynamic drag by means of computational fluid dynamics (CFD) simulations. An existing helmet frequently used in competition was taken as a baseline. Six additional helmet designs, as well as the bare-head configuration, were analysed. All the numerical simulations were performed via 3D RANS simulations using the SST k-ω turbulence model. The results show that the use of a helmet always reduces the aerodynamic drag with respect to the bare head configuration. Besides, an optimised helmet design enables a reduction of the skaters aerodynamic drag by 5.9%, with respect to the bare-head configuration, and by 1.6% with respect to the use of the baseline Omega helmet.



2021 ◽  
Vol 11 (5) ◽  
pp. 7665-7672
Author(s):  
D. Bhatia ◽  
Y. Zhao ◽  
D. Yadav ◽  
J. Wang

This paper explores the use of sharkskin in improving the aerodynamic performance of aerofoils. A biomimetic analysis of the sharkskin denticles was conducted and the denticles were incorporated on the surface of a 2-Dimensional (2D) NACA0012 aerofoil. The aerodynamic performance including the drag reduction rate, lift enhancement rate, and Lift to Drag (L/D) enhancement rate for sharkskin denticles were calculated at different locations along the chord line of the aerofoil and at different Angles of Attack (AOAs) through Computational Fluid Dynamics (CFD). Two different denticle orientations were tested. Conditional results indicate that the denticle reduces drag by 4.3% and attains an L/D enhancement ratio of 3.6%.



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