Influence of air-jet vortex generator diameter on separation region

Szwaba, Ryszard

doi:10.1007/s11630-013-0627-9

Cited by 49 publications

(10 citation statements)

References 4 publications

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“…Transition within the boundary layer can be forced through application of surface roughness [4], a turbulator step [5], or air-jet vortex generators (AJVG) [6]. Although such passive control methods are already in use for the boundary layer separation control [7,8], the mechanism of the shock wave-laminar boundary layer interaction and, in particular, the source of the strong shock unsteadiness are still not well understood. Such strong shock unsteadiness through pressure pulsations, partially driven by a separated boundary layer, often leads to unsteady loading of blades.…”

Section: Introductionmentioning

confidence: 99%

Transition Effect on the Flow Dynamics in a Compressor Blade Passage

Szwaba

Kaczyński

Telega

2021

Shock and Vibration

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An experimental investigation was carried out to study the effect of the boundary layer transition on the flow dynamics in the blade passage of a compressor cascade. A model of a turbine compressor passage was designed and assembled in a transonic wind tunnel for this purpose. Two different flow control methods were used in the experiment to induce the transition upstream of the shock wave, one concerning the microstep application and the other using distributed roughness strips. Two locations of spanwise microsteps for the transition trigger were chosen, one at the leading edge and the other closer to the shock wave position. The distributed roughness in the form of standard sandpaper strips with different heights was applied in three various locations on the blade upstream of the shock. The main objective of investigations is to present the influence of the laminar and turbulent shock wave-boundary layer interaction on the flow dynamics in a compressor fan passage, and the specific objective is to show how the parameters of particular transition control methods affect the flow dynamics in the investigated channel. The major challenge for this research was to minimize the disturbance caused by the microstep or roughness to the laminar boundary layer, while still ensuring a successful transition. Very interesting results were obtained in the flow control application for the boundary layer transition control, demonstrating a positive effect on the flow unsteadiness in changing the nature of the interaction.

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Section: Introductionmentioning

confidence: 99%

Transition Effect on the Flow Dynamics in a Compressor Blade Passage

Szwaba

Kaczyński

Telega

2021

Shock and Vibration

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“…Various types of VG devices, both active or passive, have been tested in the literature. The active approach uses plasma jets [16][17][18] or steady [19][20][21][22][23] or pulsed micro air jets [18,24] (normal or angled to the main flow), which (on interaction with the oncoming flow) generate streamwise vortices. Although the active control has the added advantage of being switched on or off as per requirement [19,20], they do require input of extra energy for their activation and, hence, may increase installation and maintenance costs.…”

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confidence: 99%

Control of Incident Shock-Induced Separation Using Vane-Type Vortex-Generating Devices

Verma

Manisankar

2018

AIAA Journal

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An experimental investigation was conducted to control an incident shock-induced boundary-layer separation associated with a 14 deg shock generator in a Mach 2.05 flow. Two vane-type configurations, namely the triangular (h∕δ 0.3, 0.5, 0.8, 1.0) and the rectangular (h∕δ 0.5) designs, were studied. An array of each control device was tested for three control locations of X∕δ 5, 10, and 15. The control location of 5δ is seen to show the maximum reduction in separation length for each device tested. For the rectangular-vane device (h∕δ 0.5), a maximum reduction of 38% in separation length is observed, followed by the triangular-vane devices of h∕δ 0.8 and 1.0, each of which shows a 32% reduction, and finally, h∕δ 0.5 with 18%. The effectiveness of these devices to control separation is, however, seen to decrease with increase in X∕δ. In terms of separation shock unsteadiness, the maximum rms value for X∕δ 5δ shows the highest value for each control device, and this value decreases with increase in control location. At X∕δ 15, both the rectangular vane (h∕δ 0.5) and triangular vane (h∕δ 0.8;1.0) show a 50% reduction in maximum rms value, whereas it decreases to 30% at X∕δ 10 for these devices.

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“…This means to find the transition location closest to the shock wave while ensuring that the interaction occurs with minimum adverse effects (such as separation, unsteadiness and large shock lambda foot). One may use different tripping devices (Szwaba, 2011;Szwaba, 2013;Szwaba et al, 2019) to induce the transition in the boundary layer; however, the presented experiments have focused on the roughness effects on aerodynamic performance of compressor fan blades passage. For this purpose, a model of a compressor passage was designed and assembled in a wind tunnel (Fomin et al, 2009) (at an institute in Gdansk) to investigate the flow structure on the suction side of the blade in a rectilinear test section of the transonic wind tunnel, Figure 1.…”

Section: Introductionmentioning

confidence: 99%

Transition effect on aerodynamic performance of compressor profile

Szwaba

Kaczyński

Doerffer

2020

AEAT

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Purpose The purpose of this paper is to study experimentally the effect of transition and also the roughness height on the flow structure of the shock wave boundary layer interaction in the blades passage of a compressor cascade. Design/methodology/approach A model of a turbine compressor passage was designed and assembled in a transonic wind tunnel. In the experiment, the distributed roughness with different heights and locations was used to induce transition upstream of the shock wave. Findings Recommendation regarding the roughness parameters for the application depends on what is more important as goal, whether the reduction of losses or unsteadiness. In case if more important are the losses reduction, a good choice for the roughness location seems to be the one close to the shock wave position. Research limitations/implications The knowledge gained by this paper will enable the implementation of an effective laminar flow technology for engines in which the interaction of a laminar boundary layer with a shock wave takes place in the propulsion system and causes severe problems. Originality/value The paper focuses on the influence of the boundary layer transition induced by different roughness values and locations on aerodynamic performance of a compressor cascade. Very valuable results were obtained in the roughness application for the boundary layer transition control, demonstrating a positive effect in changing the nature of the interaction and also some negative influence in case of oversized roughness height, which cannot be found in the existing literature.

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Influence of air-jet vortex generator diameter on separation region

Cited by 49 publications

References 4 publications

Transition Effect on the Flow Dynamics in a Compressor Blade Passage

Transition Effect on the Flow Dynamics in a Compressor Blade Passage

Control of Incident Shock-Induced Separation Using Vane-Type Vortex-Generating Devices

Transition effect on aerodynamic performance of compressor profile

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