Drag reduction capability of uniform blowing in supersonic wall-bounded turbulent flows

Kametani, Yukinori; Kotake, Ayane; Fukagata, Koji; Tokugawa, Naoko

doi:10.1103/physrevfluids.2.123904

Cited by 20 publications

(8 citation statements)

References 32 publications

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“…Both T ec and ρ w increase as T + decreases (or ω + increases), with a rapid increase of T ec and ρ w for very small T + . The variation of these thermodynamic properties will be found to play a role in affecting the drag control performance; this role is different from the control with uniform blowing and suction (Kametani et al 2017), where ρ w and T ec are not significantly altered. = 12 as a function of (a) wall-normal coordinate y + and as function of oscillation phase ϕ at (b) η = 1 (y + ≈ 6) and (c) η = π (y + ≈ 19).…”

Section: Mean Density and Temperature Profilesmentioning

confidence: 89%

“…The variation of these thermodynamic properties will be found to play a role in affecting the drag control performance; this role is different from the control with uniform blowing and suction (Kametani et al. 2017), where and are not significantly altered.…”

Section: Spanwise Wall Oscillation Atmentioning

confidence: 95%

“…Kametani et al. (2017) studied the effects of uniform blowing or suction on CTCF and found that and the net energy savings are hardly affected by the Mach number. In addition, the effect of control on thermodynamic quantities, like temperature, density and turbulent Mach number, is small.…”

Section: Introductionmentioning

confidence: 99%

“…Consistent with the incompressible case (Kametani & Fukagata 2011;Kametani et al 2015), they demonstrated that uniform blowing reduces the skin friction while uniform suction increases it; the turbulent fluctuations exhibit the opposite trend. Kametani et al (2017) studied the effects of uniform blowing or suction on CTCF and found that DR and the net energy savings are hardly affected by the Mach number. In addition, the effect of control on thermodynamic quantities, like temperature, density and turbulent Mach number, is small.…”

Section: Introductionmentioning

confidence: 99%

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Supersonic turbulent boundary layer drag control using spanwise wall oscillation

Yao

Hussain

2019

J. Fluid Mech.

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Spanwise wall oscillation has been extensively studied to explore possible drag control methods, mechanisms and efficacy – particularly for incompressible flows. We performed direct numerical simulation for fully developed turbulent channel flow to establish how effective spanwise wall oscillation is when the flow is compressible and also to document its drag reduction (${\mathcal{D}}{\mathcal{R}}$) trend with Mach number. Drag reduction ${\mathcal{D}}{\mathcal{R}}$ is first investigated for three different bulk Mach numbers $M_{b}=0.3$, $0.8$ and $1.5$ at a fixed bulk Reynolds number $Re_{b}=3000$. At a given velocity amplitude $A^{+}$ ($=12$), ${\mathcal{D}}{\mathcal{R}}$ at $M_{b}=0.3$ agrees with the strictly incompressible case; at $M_{b}=0.8$, ${\mathcal{D}}{\mathcal{R}}$ exhibits a similar trend to that at $M_{b}=0.3$: ${\mathcal{D}}{\mathcal{R}}$ increases with the oscillation period $T^{+}$ to a maximum and then decreases gradually. However, at $M_{b}=1.5$, ${\mathcal{D}}{\mathcal{R}}$ monotonically increases with $T^{+}$. In addition, the maximum ${\mathcal{D}}{\mathcal{R}}$ is found to increase with $M_{b}$. For $M_{b}=1.5$, similar to the incompressible case, ${\mathcal{D}}{\mathcal{R}}$ increases with $A^{+}$, but the rate of increase decreases at larger $A^{+}$. Unlike the flow behaviour when incompressible, the flow surprisingly relaminarizes when it is supersonic (at $A^{+}=18$ and $T^{+}=300$) – this enigmatic behaviour requires further detailed studies for different domain sizes, $Re_{b}$ and $M_{b}$. The Reynolds number effect on ${\mathcal{D}}{\mathcal{R}}$ is also investigated. Although ${\mathcal{D}}{\mathcal{R}}$ generally decreases with $Re_{b}$, it is less affected at small $T^{+}$, but drops rapidly at large $T^{+}$. We introduce a simple scaling for the oscillation period as $T^{\ast }=T_{C}^{+}l_{I}^{+}/l_{C}^{+}$, with $l_{I}^{+}$ and $l_{C}^{+}$ denoting the mean streak spacing for incompressible and compressible cases, respectively. At the same semi-local Reynolds number $Re_{\unicode[STIX]{x1D70F}c}^{\ast }\equiv Re_{\unicode[STIX]{x1D70F}}\sqrt{\overline{\unicode[STIX]{x1D70C}}_{c}/\overline{\unicode[STIX]{x1D70C}}_{w}}/(\overline{\unicode[STIX]{x1D707}}_{c}/\overline{\unicode[STIX]{x1D707}}_{w})$ (subscripts $c$ and $w$ denote quantities at the channel centre and wall, respectively), ${\mathcal{D}}{\mathcal{R}}$ as a function of $T^{\ast }$ exhibits good agreement between the supersonic and strictly incompressible cases, with the optimal oscillation period becoming $M_{b}$-invariant as $T_{opt}^{\ast }\approx 100$.

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Section: Mean Density and Temperature Profilesmentioning

confidence: 89%

Section: Spanwise Wall Oscillation Atmentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Supersonic turbulent boundary layer drag control using spanwise wall oscillation

Yao

Hussain

2019

J. Fluid Mech.

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“…They also elucidated the reduction mechanism of turbulent skin friction by an analysis using Fukagata-Iwamoto-Kasagi (FIK) identity (Fukagata et al, 2002). In addition, friction drag reduction effect of UB was also confirmed at higher Reynolds numbers (Kametani et al, 2015) and Mach numbers (Kametani et al, 2017), and with intermittent slots (Kametani et al, 2016) and on a rough wall (Mori et al, 2017).…”

Section: Introductionmentioning

confidence: 86%

Experimental investigation on friction drag reduction on an airfoil by passive blowing

Hirokawa¹,

Eto²,

Fukagata³

et al. 2020

JFST

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Friction drag reduction effect of a passive blowing on a Clark-Y airfoil is investigated. Uniform blowing, conducted in a wall-normal direction on a relatively wide surface, is generally known as an active control method for reduction of turbulent skin friction drag. In the present study, uniform blowing is passively driven by the pressure difference on a wing surface between suction and blowing regions. The suction and the blowing regions are respectively set around the leading edge and the rear part of the upper surface of the Clark-Y airfoil in order to ensure a sufficient pressure difference for passive blowing. The Reynolds number based on the chord length is 0.65×10 6 and 1.55×10 6. The angle of attack is set to 0 • and 6 •. The mean streamwise velocity profiles on the blowing region and the downstream, measured by a traversed hot-wire anemometry, are observed to shift away from the wall by passive blowing. This behavior qualitatively suggests reduction of local skin friction on the wing surface. A quantitative assessment of the friction drag is performed using the law of the wall accounting for pressure gradients (Nickels, 2004), coupled with a modified Stevenson's law (Vigdorovich, 2016) to account for the weak blowing. From this assessment, the local friction drag reduction effect of passive blowing is estimated to reach 4% − 23%.

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Turbulent Friction Drag Reduction: From Feedback to Predetermined, and Feedback Again

Fukagata

2021

Fluid-Structure-Sound Interactions and Control

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Drag reduction capability of uniform blowing in supersonic wall-bounded turbulent flows

Cited by 20 publications

References 32 publications

Supersonic turbulent boundary layer drag control using spanwise wall oscillation

Supersonic turbulent boundary layer drag control using spanwise wall oscillation

Experimental investigation on friction drag reduction on an airfoil by passive blowing

Turbulent Friction Drag Reduction: From Feedback to Predetermined, and Feedback Again

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