The influence of riblets on a boundary layer with embedded streamwise vortices

Grek, G. R.; Козлов, В. В.; Titarenko, S. V.; Klingmann, Barbro G. B.

doi:10.1063/1.868694

Cited by 27 publications

(9 citation statements)

References 2 publications

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“…Bakchinov, Grek, Klingmann and Kozlov (1995) in a model experiment generated the boundary layer vortices by roughness elements located periodically along the span of the flat plate. The traveling disturbances inside the vortices were excited by a vibrating ribbon.…”

Section: Late Stages Of Transitionmentioning

confidence: 99%

“…Wind-tunnel experiments on the boundary-layer stability at wall cooling were carried out by Kachanov . Effect of riblets on transitional flat-plate boundary layer modulated by stationary streamwise vortices (Grek et al, 1995). Transversal variations of the mean flow (a) and amplitude of natural disturbances (b) on the smooth (•) and ribbed (•) surfaces at Rex = 2.5 × 10 5 .…”

Section: Flow Control Techniquesmentioning

confidence: 99%

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Origin of Turbulence in Near-Wall Flows

Boiko

Grek²,

Dovgal

et al. 2003

Applied Mechanics Reviews

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The origin of turbulence in fluids is a long-standing problem being in focus of researches through decades due to its great importance in a variety of engineering applications. Meanwhile, the study of turbulence origin is a part of the fundamental physical problem of the turbulence description and the philosophical problem of determinism and chaos. This paper is concern to a review of new findings in the field of laminar-turbulent transition of near-wall flows.

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Section: Late Stages Of Transitionmentioning

confidence: 99%

Section: Flow Control Techniquesmentioning

confidence: 99%

Origin of Turbulence in Near-Wall Flows

Boiko

Grek²,

Dovgal

et al. 2003

Applied Mechanics Reviews

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“…Tu Структура Влияние возмущений [6] 0.3 0.05-0.36 случайные возмущения ускорение перехода [7] 0.6-3.0 ≥ 0.55 случайные возмущения замедление перехода [8,9] < 0.04 0.63-1.25 продольные вихри подавление вихрей [10] < 0.04 1.15-1.35 волны Т-Ш усиление волн Введение В качестве пояснения заметим, что в случае высокой степени турбулентности набегающего потока (Tu = 0.6-3.0) в случайных возмущениях пограничного слоя доминируют продольные вихри, характерные для докритического перехода, а при меньшей степени турбулентности набегающего потока -волны Толлмина-Шлихтинга. В экспериментах с контролируемыми возмущениями продольные вихри создают специальными методами и при малой степени турбулентности.…”

Section: источникunclassified

Stability of shear flows over a grooved surface

Бойко¹,

Klyushnev²,

Nechepurenko³

2016

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“…In [6], the growth of these disturbances was suppressed by wall oscillations in the transverse direction, and in [7] by means of riblets. Studies have been performed of the effect of riblets on longitudinal vortices generated using roughness elements in the boundary layer on a flat plate [8] and on an oblique wing [9]. These studies were successful in the sense that a decrease in disturbance energy was achieved using control.…”

mentioning

confidence: 98%

Controlling the Development of Stationary Longitudinal Structures in the Boundary Layer on a Flat Plate using Riblets

Lokhov

Бойко

Sboev

2005

J Appl Mech Tech Phys

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This paper reports results of experiments on controlling longitudinal structures in the boundary layer on a flat plate. The longitudinal structures were generated by a controlled vortical disturbance of the external flow by means of a distributed susceptibility mechanism. It is shown that riblets reduce the intensity of both stationary and traveling disturbances. The linear and weakly linear stages in the development of disturbances in the boundary layer are the most favorable for the use of riblets.Introduction. It is known that in many cases, laminar-turbulent transitions are dominated by longitudinal structures. An example is a transition under conditions of elevated free-stream turbulence. Subsequently, the longitudinal structures that arise in this case undergo secondary instability, resulting in turbulent spots [1].At present, the mechanisms of occurrence of longitudinal structures in boundary layers as primary instability under natural conditions have not been clarified. Model experiments have shown that generation of these disturbances by external turbulence can be implemented by means of both localized [2] and distributed [3,4] susceptibilities.There have been few experiments on controlling the development of longitudinal structures in boundary layers. Katasonov and Kozlov [5] employed a method of active control of longitudinal structures localized in space and time (so-called puffs) using localized injection-suction through a hole in the wall. In [6], the growth of these disturbances was suppressed by wall oscillations in the transverse direction, and in [7] by means of riblets. Studies have been performed of the effect of riblets on longitudinal vortices generated using roughness elements in the boundary layer on a flat plate [8] and on an oblique wing [9]. These studies were successful in the sense that a decrease in disturbance energy was achieved using control. It should be noted that all these experiments dealt with controlling disturbances generated by localized susceptibility mechanisms.The distributed generation of a stationary longitudinal structure in a laminar boundary layer on a flat plate was is studied in detail in [3,4]. The data of these experiments are in good agreement with the results of theoretical papers [10][11][12]. In contrast to localized generation, distributed susceptibility ensures a continuous energy flow from external disturbances to disturbances inside the boundary layer [13], which can reduce the control effectiveness. Research on the control of the disturbances resulting from distributed susceptibility has not yet been performed and is therefore very important.Riblets, as is known, are a longitudinal ribbing of a body surface and are an effective passive means for controlling the boundary layer in both turbulent flows [14] and in the early nonlinear stages of laminar-turbulent transitions [15]. Their advantages are ease in manufacturing and stability against external action. Laminarturbulent transitions under high free-stream turbulence conditions are frequently encounte...

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The influence of riblets on a boundary layer with embedded streamwise vortices

Cited by 27 publications

References 2 publications

Origin of Turbulence in Near-Wall Flows

Origin of Turbulence in Near-Wall Flows

Stability of shear flows over a grooved surface

Controlling the Development of Stationary Longitudinal Structures in the Boundary Layer on a Flat Plate using Riblets

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