Active Flow Control for Reducing Drag on Trucks: from Concept to Full Scale Testing
Doctoral thesis, 2017

There is no doubt that road vehicle transportation is needed to improve efficiency, to reduce power consumption and to contribute to a sustainable mobility. Aerodynamics plays a crucial role in this, and its optimization can have a significant impact on fuel efficiency. The work reported in this thesis thus investigates the applicability of an active flow control technique able to improve the aerodynamic performance of trucks. CFD simulations and wind tunnel experiments are conducted to explore the potential of such a device. The process starts with a preliminary LES study (Re = 1 × 10^5 ) and ends with a proof of concept full scale test of a real truck (Re = 3.5 × 10^6 ). The PANS method and scaled model wind tunnel experiments were essential to bridge the initial preliminary findings to the final full scale test. PANS was first validated (using in-house experimental data and data from test cases) and then used to simulate the efficacy of AFC at higher Re (Re = 5 × 10^5 ), introducing realistic flow conditions (wind gusts). In addition, wind tunnel experiments of a scaled, simplified truck cabin were used to demonstrate the applicability of the control. The results focus on two main points. First, synthetic jets were shown to be an effective and low energy consumption technique to control a pressure induced separated flow and for reducing drag on trucks. Second, PANS was shown to be an interesting method for industrial applications. Its capability to resolve unsteady flow cases preserving the accuracy of the flow structures prediction is shown, even when meshes are relatively coarse.



Vehicle Aerodynamics

Partially-Averaged Navier-Stokes



Wind Tunnel


Active Flow Control

Large Eddy Simulations

Proper Orthogonal Decomposition


KB-salen, Kemigården 4, Chalmers.
Opponent: Prof. Dr.-Ing. Suad Jakirlic, Institute of Fluid Mechanics and Aerodynamics/Center of Smart Interfaces, Technische Universität Darmstadt, Germany.


Guglielmo Minelli

Chalmers, Applied Mechanics, Fluid Dynamics

Partially-averaged Navier–Stokes simulations of two bluff body flows

Applied Mathematics and Computation,; Vol. 272(2016)p. 692-706

Journal article

Numerical Investigation of Active Flow Control Around a Generic Truck A-Pillar

Flow, Turbulence and Combustion,; Vol. 97(2016)p. 1-20

Journal article

Validation of PANS and active flow control for a generic truck cabin

Journal of Wind Engineering and Industrial Aerodynamics,; Vol. 171(2017)p. 148-160

Journal article

Aerodynamic flow control for a generic truck cabin using synthetic jets

Journal of Wind Engineering and Industrial Aerodynamics,; Vol. 168(2017)p. 81-90

Journal article

G. Minelli, S. Krajnović, B. Basara, "A Flow Control Study of a Simplified, Oscillating Truck Cabin using PANS" in Journal of Fluid Engineering. Under review

G. Minelli, A. Hartono, V. Chernoray, L. Hjelm, B. Basara, S. Krajnović, "Development of Active Flow Control for Trucks" in the 3rd Thermal and Fluids Engineering Conference (TFEC), March 4–7, 2018, Fort Lauderdale, FL, USA

Aerodynamic drag accounts for more than 60% of the total power consumption of a travelling truck at cruise speed. The need for a better aerodynamic is therefore clear and a small improvement of the aero-package of a truck can have a significant impact on the total power consumption. Hence, the active flow control (AFC) technique is introduced as an effective aerodynamic feature of future trucks.

The study of this methodology is the result of a collaboration between Chalmers University of Technology and Volvo Trucks AB. The results obtained are not only published to enrich the specific scientific community of flow control, but are also used as a cornerstone for the future implementation of active flow control on real vehicles.

The findings reported in this thesis summarize in fact the work flow of almost four years of research. The presented work spans the process from a theoretical verification of the method to a preliminary implementation of an AFC on a real full scale truck cabin.

From this point on, a continued research will be able to integrate and optimize this technology for a larger scale production and finally contribute to the ”zero emission vision” European countries are striving for.

Areas of Advance


Subject Categories

Aerospace Engineering

Vehicle Engineering

Fluid Mechanics and Acoustics



Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4343



KB-salen, Kemigården 4, Chalmers.

Opponent: Prof. Dr.-Ing. Suad Jakirlic, Institute of Fluid Mechanics and Aerodynamics/Center of Smart Interfaces, Technische Universität Darmstadt, Germany.

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