Turbulence in Plasma-Induced Hypersonic Drag Reduction

Appartaim, Richard; Mezonlin, Ephrem; Johnson, J. A.

doi:10.2514/2.1559

Cited by 15 publications

(5 citation statements)

References 11 publications

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“…The measured drag reduction was too large to be attributed to the thermal effect. The subsequent wind tunnel experiments by other investigators [3][4][5][6][7][8] showed that the shock front increased dispersion in its structure and/or standoff distance from the model when plasma was generated ahead of a model either by off-board/on-board electric discharges. In the experiments conducted by Bivolaru and Kuo [7,8], a wind tunnel model of truncated 60 0 cone, with a slender central-spike protruding out of the cut circular cross section to the tip location of a perfect cone, was used.…”

Section: Introductionmentioning

confidence: 98%

Nonthermal Plasma Mitigation of Shock Wave in Supersonic Airflow~!2009-04-01~!2009-05-11~!2009-07-16~!

Kuo¹

2009

TOPPJ

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A non-thermal technique using a plasma spike, generated by 60 Hz periodic electric discharge, for shock wave mitigation is presented. The experiments were conducted in a Mach 2.5 wind tunnel. A plasma spike was generated in front of a wind tunnel model; it led to a transformation of the shock from a well-defined attached shock into a highly curved shock structure, which had increased shock angle and also appeared in diffused form. As seen in a sequence with increasing discharge intensity, the shock in front of the model moved upstream to become detached with increasing standoff distance from the model and was eliminated near the peak of the discharge. The power measurements excluded the heating effect as a possible cause of the observed shock wave modification. A theory using a cone model as the shock wave generator is presented to explain the observed plasma effect on shock wave. The analysis has shown that the plasma generated in front of the model can effectively deflect the incoming flow; such a flow deflection modifies the structure of the shock wave generated by the cone model, as shown by the numerical results, from a conic shape to a curved one. The shock front moves upstream with a larger shock angle, matching well with that observed in the experiment.

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Section: Introductionmentioning

confidence: 98%

Nonthermal Plasma Mitigation of Shock Wave in Supersonic Airflow~!2009-04-01~!2009-05-11~!2009-07-16~!

Kuo¹

2009

TOPPJ

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“…Meanwhile, viscous drag can be further reduced more than 40% through flow-control technologies, which is equivalent to about 15% of the total drag [2]. With the exploration of drag reduction technologies, a variety of viscous drag reduction methods have been proposed and developed, such as plasma method [3], periodic perturbation method [4], push-pull airflow method [5], and separation suppression method [6], which can be roughly ranged to active drag reduction methods. However, extra applying control devices and additional energy consumption are required to implement these methods for drag reduction, leading to the limitations in industrial applications.…”

Section: Introductionmentioning

confidence: 99%

Drag Reduction Characteristics of Microstructure Inspired by the Cross Section of Barchan Dunes under High Speed Flow Condition

Jiang¹,

Shen²,

Tao³

et al. 2022

Journal of Renewable Materials

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A new type of microstructure inspired by the cross section of barchan dunes was proposed to reduce windage, which was considered as a passive drag reduction technology in aerospace manufacturing field. Computational fluid dynamics method was carried out to discuss the effect of the microstructure on the skin friction reduction under high velocity flow condition. Different microstructure heights were employed to survey the reduction of drag. The results illustrated that the appearance of microstructure led to a generation of pressure drag in nonsmooth model (with microstructures inspired by cross section of barchan dune) in contrast to smooth model. However, the microstructure significantly increased the thickness of the low-speed fluid by 11.4% in the near-wall flow field, causing the low-speed fluid to rise and decreasing the velocity gradient near the wall, thereby reducing viscous resistance. In addition, high-speed fluid flowed above the microstructure units instead of along the inner side of the units due to the influence of micro-vortex, resulting in a reduction of friction near the surface. Furthermore, micro-vortex was considered to be the significant internal factor to achieve turbulent drag reduction since it could not only reduce the viscous resistance by promoting the fluid flow above the microstructure but also provide a reverse thrust force. The understanding of the mechanism of drag reduction provides theoretical guidance for further fabrication of drag reduction coatings using renewable materials.

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“…Notably, viscous drag can be further reduced by 40% with flow-control technologies, which is equal to approximately 15% of the windage [2]. With the development of drag reduction technologies, several viscous drag reduction methods have been proposed, such as the plasma method [3], periodic perturbation method [4], push-pull airflow method, [5] and separation suppression method [6]. These methods are classified as active drag reduction methods due to the requirements extra applying extra control devices and additional energy consumption, which severely limit their application in aviation industry.…”

Section: Introductionmentioning

confidence: 99%

Rational Analysis of Drag Reduction Variation Induced by Surface Microstructures Inspired by the Middle Section of Barchan Dunes at High Flow Velocity

Jiang

Shen

et al. 2022

Coatings

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Aerodynamic drag reduction is a key element for the design of aircrafts, and it is also considered to be affected by the flow velocity. Herein, the influence of high flow velocity on the drag reduction induced by the surface microstructure inspired by a cross-section of barchan dune was investigated by the computational fluid dynamics method in this work. Overall, the drag reduction ratio was decreased while the pressure drag and viscous resistance enhanced simultaneously with the augmentation of flow velocity. Otherwise, drag analysis revealed that the total drag was a power function of flow velocity, which meant that the effect of flow velocity on drag was extremely fierce. Additionally, the microstructure improved the thickness of the boundary layer with a growth rate of 14.2%, and then reduced the viscosity resistance with limits during the development process of flow velocity. Furthermore, the micro-vortex caused by the surface microstructure provided the reverse wall shear stress, with the maximum value ranging from −4.77 Pa to −51.27 Pa, and then reduced the velocity gradient above the microstructure, thereby improving the drag reduction. However, both Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) calculations showed that the excessive velocity could lead to the dissipation of micro-vortex, which augmented the contact area between the fluid and the surface, resulting in the enlargement of viscous resistance. Finally, it was confirmed that the variation of surface microstructure height had a significant influence on drag reduction at high flow velocity. The underlying mechanism of drag reduction could also provide theoretical guidance for the design and optimization of drag reduction coatings in aeronautical applications.

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Turbulence in Plasma-Induced Hypersonic Drag Reduction

Cited by 15 publications

References 11 publications

Nonthermal Plasma Mitigation of Shock Wave in Supersonic Airflow~!2009-04-01~!2009-05-11~!2009-07-16~!

Nonthermal Plasma Mitigation of Shock Wave in Supersonic Airflow~!2009-04-01~!2009-05-11~!2009-07-16~!

Drag Reduction Characteristics of Microstructure Inspired by the Cross Section of Barchan Dunes under High Speed Flow Condition

Rational Analysis of Drag Reduction Variation Induced by Surface Microstructures Inspired by the Middle Section of Barchan Dunes at High Flow Velocity

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