Modern Developments in Flow Control

Gad‐el‐Hak, Mohamed

doi:10.1115/1.3101931

Cited by 250 publications

(114 citation statements)

References 101 publications

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“…The increase of minimum value of pressure coefficient of 26.17% has been obtained. It indicates that the application of suction in the reversed Ahmed Body was able to reduce the total pressure loss and increase the static pressure at the surface of the object or model such as already been indicated by other studies [19][20][21].…”

Section: Resultssupporting

confidence: 67%

Modification of Flow Structure Over a Van Model by Suction Flow Control to Reduce Aerodynamics Drag

Harinaldi¹,

Budiarso²,

Warjito³

et al. 2012

MST

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Automobile aerodynamic studies are typically undertaken to improve safety and increase fuel efficiency as well as to find new innovation in automobile technology to deal with the problem of energy crisis and global warming. Some car companies have the objective to develop control solutions that enable to reduce the aerodynamic drag of vehicle and significant modification progress is still possible by reducing the mass, rolling friction or aerodynamic drag. Some flow control method provides the possibility to modify the flow separation to reduce the development of the swirling structures around the vehicle. In this study, a family van is modeled with a modified form of Ahmed's body by changing the orientation of the flow from its original form (modified/reversed Ahmed body). This model is equipped with a suction on the rear side to comprehensively examine the pressure field modifications that occur. The investigation combines computational and experimental work. Computational approach used a commercial software with standard kepsilon flow turbulence model, and the objectives was to determine the characteristics of the flow field and aerodynamic drag reduction that occurred in the test model. Experimental approach used load cell in order to validate the aerodynamic drag reduction obtained by computational approach. The results show that the application of a suction in the rear part of the van model give the effect of reducing the wake and the vortex formation. Futhermore, aerodynamic drag reduction close to 13.86% for the computational approach and 16.32% for the experimental have been obtained. Abstrak Modifikasi Struktur Aliran pada Model Kendaraan Van dengan Kontrol Aliran Hisapan untuk MengurangiHambatan Aerodinamika. Studi aerodinamika kendaraan biasanya berkaitan dengan keselamatan dan peningkatan efisiensi bahan bakar serta penemuan inovasi baru dalam teknologi kendaraan untuk mengatasi masalah krisis energi dan pemanasan global. Beberapa perusahaan mobil memiliki tujuan untuk mengembangkan solusi kontrol yang memungkinkan pengurangan hambatan aerodinamika kendaraan seiring dengan kemajuan modifikasi kendaraan yang masih dapat dilakukan dengan cara mengurangi massa, rolling friction atau hambatan aerodinamika. Beberapa metode kontrol aliran memberikan kemungkinan dalam memodifikasi pemisahan aliran untuk mengurangi terbentuknya swirling structure di sekitar kendaraan. Dalam studi ini, sebuah kendaraan keluarga dimodelkan dengan memodifikasi Ahmed body dengan mengubah orientasi aliran dari bentuk aslinya (modifikasi Ahmed body/reversed Ahmed body). Model ini dilengkapi dengan hisapan pada sisi belakang untuk memeriksa secara komprehensif perubahan medan tekanan yang terjadi. Penelitian dilakukan dengan pendekatan komputasi dan eksperimental. Pendekatan komputasi menggunakan perangkat lunak komersial dengan model turbulensi aliran k-epsilon standar dan bertujuan untuk mengetahui karakteristik medan aliran dan pengurangan hambatan aerodinamika yang terjadi pada model uji. Pendekatan eksperimental mengg...

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Section: Resultssupporting

confidence: 67%

Modification of Flow Structure Over a Van Model by Suction Flow Control to Reduce Aerodynamics Drag

Harinaldi¹,

Budiarso²,

Warjito³

et al. 2012

MST

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“…Application of active flow control methods [1] to delay the flow separation on the flap of modern transport aircraft has been the subject of research for many years. An active flow control technique that is of particular interest to us is the predetermined or the so-called open-loop active flow control approach.…”

Section: Introductionmentioning

confidence: 99%

A Two-Level Hybrid Approach for Optimal Active Flow Control on a Three-Element Airfoil

Nemili¹,

Özkaya²,

Gauger³

et al. 2016

Proceedings of the VII European Congress on Computational Methods in Applied Sciences and Engineering (ECCOMAS Congress 2016)

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Abstract. In this paper we present a two-level approach that combines an adjoint-based gradient search method with an evolutionary algorithm for optimal active flow control. The suggested method effectively combines the advantages of both approaches and achieves a good compromise between the computational effort and the degree of freedom used in optimization. In the first level, a global optimization is performed with few design parameters using an evolutionary algorithm. In the second level, the global optimal solution from the first level is taken as the initial setting for the adjoint based local optimization using a large number of design parameters. The unsteady discrete adjoint solver required for the second level is developed based on Algorithmic Differentiation techniques for the unsteady incompressible flowsgoverned by Unsteady Reynolds-Averaged Navier Stokes (URANS) equations. In this way, the discrete adjoint solver is robust and has exactly the same functionality with the underlying URANS flow solver. The applicability of the two-level method is demonstrated by finding the optimal parameters of the active flow control mechanism on a three element airfoil configuration at a Reynolds number of Re = 10 6 and an angle of attack of AoA = 6 • . Numerical results have shown that the hybrid approach completely suppressed the separation and very significantly increased the mean-lift coefficient by 67% compared to the un-actuated baseline flow.

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“…There are some other techniques that are applied away from the wall. Some are as follows: Large-eddy breakup devices (also called outer-layer devices, or OLDs, acoustic waves bombarding a shear layer from outside [6] , additives introduced in the middle of a shear layer, manipulation of freestream turbulence levels and spectra, gust and magneto and electrohydrodynamic body forces [7] .…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Flow Control by Suction and Injection on a Subsonic Airfoil

Shojaefard¹,

Noorpoor²,

Avanesians³

et al. 2005

American J. of Applied Sciences

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This study presents a numerical study concerning flow control by suction and injection. The case studied is the flow field over a subsonic airfoil with four suction and injection slots on the suction side of the airfoil. Five different angles of attack, 0, 5, 10, 13.3 and 20 with the Mach number of 0.15 are studied. Three cases are studied in each angle of attack. The three cases are airfoil with surface suction, surface injection and the base airfoil. A commercial CFD code, the FLUENT, is used in this study. The effect of suction and injection on aerodynamic coefficients is investigated. The results show that the surface suction can significantly increase the lift coefficient. The injection decreases the skin friction.

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Modern Developments in Flow Control

Cited by 250 publications

References 101 publications

Modification of Flow Structure Over a Van Model by Suction Flow Control to Reduce Aerodynamics Drag

Modification of Flow Structure Over a Van Model by Suction Flow Control to Reduce Aerodynamics Drag

A Two-Level Hybrid Approach for Optimal Active Flow Control on a Three-Element Airfoil

Numerical Investigation of Flow Control by Suction and Injection on a Subsonic Airfoil

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