Influence of Jet Spacing and Injection Pressure on Separation Control with Air-Jet Vortex Generators

Ramaswamy, Deepak Prem; Hinke, Rasmus; Schreyer, Anne-Marie

doi:10.1007/978-3-030-25253-3_23

Cited by 10 publications

(6 citation statements)

References 18 publications

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“…For similar conditions, the best control effect would be achieved for D ≈ 9.5d. These considerations agree nicely with the observed best control effects of AJVG set-ups with jet spacings in the range 7d ≤ D ≤ 13d (Verma & Manisankar 2019;Ramaswamy et al 2020).…”

Section: Turbulent Coherent Structures and Their Interactionsupporting

confidence: 85%

“…When the jets are placed too closely together (e.g. 4d), they form a merged bow shock spanning the entire row of jets (see Ramaswamy et al 2020). For moderate spacings (7d-13d), the individual bow shocks overlap, resulting in a wrinkled shock pattern (see also our oil-flow visualizations in figure 5).…”

Section: Influence Of Single-row Ajvg Arrays On Shock-induced Separationmentioning

confidence: 90%

“…The placement of spanwise-inclined jets in an array affects their separation-control effectiveness. The control efficiency is best for moderate injection pressure and jet spacing (Ramaswamy et al 2020;Ramaswamy & Schreyer 2022). It deteriorates for values below and above a certain range, which was attributed to varying degrees of interaction between the jet-induced structures.…”

Section: Influence Of Single-row Ajvg Arrays On Shock-induced Separationmentioning

confidence: 99%

“…Experimentally, the effect of jet spacing in spanwise-inclined jet injection with D = 32d, 16d, 8d, 4d was studied on a 24 • compression-ramp model installed on a flat plate with total length 902 mm. The model spanned the entire width of the test section (see Ramaswamy et al (2020) for more detailed information on the experimental set-up). Interchangeable AJVG inserts with one row of air-jet orifices are installed in the flat-plate model at 61.7δ downstream of the leading edge (7.69δ 99 upstream of the ramp corner).…”

Section: Experimental Configurationmentioning

confidence: 99%

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Influence of jet spacing in spanwise-inclined jet injection in supersonic crossflow

Sebastian

Schreyer

2022

J. Fluid Mech.

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In separation control with air-jet vortex generators in supersonic flow, the spacing of the jets in a row array has a crucial effect on the control effectiveness. Previous experimental studies have revealed the overall influence of jet spacing on air-jet vortex generator controlled shock-induced separation zones, focusing mostly on the separation regions. There is, however, a gap in knowledge regarding the mechanisms leading to these changes in control effectiveness, particularly on the interaction between multiple jets and the details of downstream flow evolution. Therefore, the objective of the current study is to provide detailed information on the underlying flow dynamics associated with the injection of a row of spanwise-inclined jets into a supersonic turbulent boundary layer – and in particular the effects of different jet spacings. Four different spacings were studied with large-eddy simulations. In addition, we performed oil-flow and schlieren visualizations of separation control in a 24 $^\circ$ compression–ramp interaction with different jet-spacing configurations to validate and discuss our conclusions regarding the effects of jet/jet interactions on the separation-control effectiveness. We analyse the influence of jet spacing on the flow topology, induced vortical structures, and boundary-layer statistics. The jet-induced major vortex pair is the dominant flow structure energizing the near-wall boundary layer. The paper details how interactions amongst adjacent vortex pairs differ for varying jet spacings, thus influencing the momentum transfer and eventually the control efficiency. The dynamic behaviour of the flow was analysed using a three-dimensional dynamic mode decomposition. The resulting insights are key to the development of efficient control set-ups.

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Section: Turbulent Coherent Structures and Their Interactionsupporting

confidence: 85%

Section: Influence Of Single-row Ajvg Arrays On Shock-induced Separationmentioning

confidence: 90%

Section: Influence Of Single-row Ajvg Arrays On Shock-induced Separationmentioning

confidence: 99%

Section: Experimental Configurationmentioning

confidence: 99%

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Influence of jet spacing in spanwise-inclined jet injection in supersonic crossflow

Sebastian

Schreyer

2022

J. Fluid Mech.

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“…Further, the effect of injection through micro ramp on SWBLI control is reported by Vaisakh and Muruganandam 14 and the results suggest an increase in pressure recovery. Recently an experimental study on the effect of jet spacing and injection pressure on the mitigation of SWBLI in a constant area diffuser is presented by Ramaswamy et al 15,16 and effect of micro jet on controlling the separation inside rocket nozzle is demonstrated by Khobragade et al 17 From the above review it can be concluded that the vortices created by the mixing of free stream and jet blown through air jet (AJ) reduce the SWBLI significantly. Since the use of AJ has not been investigated yet for improving the performance of supersonic air intake, the present study aims to explore the usefulness of AJ in improving the performance and overall flow field of supersonic mixed compression air intake.…”

Section: Introductionmentioning

confidence: 99%

Effect of air jet with injection pressure on the performance of mixed compression air intake

Gahlot

Singh

2020

Proceedings of the Institution of Mechanical Engineers, Part G:

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A computational study on the performance of mixed compression supersonic air intake has been carried out with and without air jet at various operating conditions. Commercially available software ANSYS was used and K-ω SST turbulence model was selected to capture the turbulent flow inside the air intake. All the simulations were simulated at a design Mach number of 2.2. Two Air jet of 1 mm diameter each and perpendicular to the local ramp surface have been placed in longitudinal direction at 0.47 times the total length of the air intake. Effect of variation of injection pressure on the flow field of air intake has been studied. Injection pressure has been varied with respect to the free stream pressure. Four different cases of injection pressure have been investigated. Three different positions (1.far away before the air jet, 2. immediately after the air jet and 3. far away behind the air jet) of normal shock were simulated to study the effect of air jet by varying the back pressure of the supersonic air intake. Significant reduction in the flow separation due the normal shock wave was noticed for all the cases of injection pressure, which further helps in improving the performance of the supersonic air intake. Important performance parameters such as flow distortion, mass flow ratio and total pressure recovery were calculated to measure the efficacy of supersonic air intake with air jet at various operating conditions.

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Effects of Jet-Orifice Shape on the Flow-Control Effectiveness of Air-Jet Vortex Generators

Ramaswamy,

Schreyer

2023

Notes on Numerical Fluid Mechanics and Multidisciplinary Design

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Influence of Jet Spacing and Injection Pressure on Separation Control with Air-Jet Vortex Generators

Cited by 10 publications

References 18 publications

Influence of jet spacing in spanwise-inclined jet injection in supersonic crossflow

Influence of jet spacing in spanwise-inclined jet injection in supersonic crossflow

Effect of air jet with injection pressure on the performance of mixed compression air intake

Effects of Jet-Orifice Shape on the Flow-Control Effectiveness of Air-Jet Vortex Generators

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