Passive Flow Control for the Load Reduction of Transonic Launcher Afterbodies

Scharnowski, Sven; Bosyk, Mickael; Schrijer, F.F.J.; Oudheusden, B.W. van

doi:10.2514/1.j057357

Cited by 5 publications

(4 citation statements)

References 38 publications

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“…Some advanced instruments and materials such as high-frequency oscillating hot wire (OHW) sensors [3] and platinumporphyrin complexes (PtTFPP) [4] are also used to study the pressure dynamics on the axisymmetric after-body. In order to explore an effective control method for the separated flow behind the axisymmetric after-body, Scharnowski et al [5] used Particle Image Velocimetry (PIV) technology to study the effect of adding control loops at the trailing edge of the after-body. It was shown that the rectangular and circular control loops are beneficial to enhance the mixing of the shear layer and can reduce the reattachment length and the pressure fluctuation.…”

Section: Introductionmentioning

confidence: 99%

“…These studies provide strong support for the understanding and control of the separated flow behind the axisymmetric after-body, but the unsteady mechanism is still unclear and the control methods are less understood. For example, Scharnowski et al [5] added control loops at the trailing edge of the afterbody, although the pressure fluctuation was reduced, but they did not further analyze the asymmetry caused by the control 109-2 loops in the azimuthal direction. The asymmetric force in the azimuthal direction may destabilize the rocket, which is a significant basis for evaluating the quality of the flow control method.…”

Section: Introductionmentioning

confidence: 99%

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Flow Separation behind an Axisymmetric After-body and Impact of Grooves at Trailing Edge

Lu¹,

Lai²

2022

International Conference on Fluid Flow and Thermal Science

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In this paper, Embedded Large Eddy Simulation (ELES) is used to study the separated flow behind an axisymmetric afterbody of rocket. The impacts of grooves added to the end of main body for passive load control are discussed. Three cases include the original after-body without groove (Prototype), with 6 grooves in azimuthal direction (Groove6), and with 12 grooves (Groove12) are compared and analysed. The pressure fluctuation on the after-body wall are analysed by using the Proper Orthogonal Decomposition (POD) method. The results show that the added grooves at the trailing edge can promote the flow mixing in the shear layer, so that the size of the separated flow zone with high pressure fluctuation is reduced in the flow direction, which is beneficial to improve the stability of the afterbody. The POD analysis is focused on the anti-symmetric mode (m=1) which characterizes the azimuthal instability. The results show that the energy proportion of the single helical mode (m=1) decreases in Groove6 and Groove12 cases, and the decrease is relatively significant in Groove6 case. This mode is an antisymmetric mode, and reducing its energy proportion is beneficial to improve stability.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Flow Separation behind an Axisymmetric After-body and Impact of Grooves at Trailing Edge

Lu¹,

Lai²

2022

International Conference on Fluid Flow and Thermal Science

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“…However, a long nozzle increases the lever arm and, thus, the effect of buffeting, which is of course an additional risk. To overcome this issue, passive flow control devices at the end of the main body could be used to enhance shear layer mixing and to reduce pressure fluctuations at reattachment [7,36].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the base flow of a generic space launcher with dual-bell nozzle

Scharnowski

Kähler

2020

CEAS Space J

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The typical afterbody flow of a space launcher is characterized by a strong interaction of the engine’s exhaust jet and the separated shear layer emerging from the main body. This interaction is further complicated by strong changes in the spatial and temporal behavior of the afterbody flow during the atmospheric ascent of a launcher. Theoretically, a dual-bell nozzle not only allows for a gain in payload compared to standard single-bell nozzles, but also it alters the wake flow topology due to the two nozzle modes. To predict the benefits as well as the additional risks, the afterbody flow of a generic space launcher model equipped with a cold-flow dual-bell nozzle is investigated in detail. The flow was analyzed for sub-, trans- and supersonic Mach numbers ranging from 0.3 to 2.9 for a variety of nozzle pressure ratios. Particle image velocimetry measurements and schlieren measurements with high repetition rate were performed to determine the dynamics of the separated shear layer, the nozzle jet and their interaction. It is shown that the reattachment length of the base flow decreases with increasing nozzle pressure ratio. Furthermore, the nozzle pressure ratio at which the dual-bell nozzle switches from sea-level mode to altitude mode is reduced by $$15\%$$ 15 % with high subsonic outer flow and by as much as $$65\%$$ 65 % for an outer flow at a Mach number of 1.6. Even for a constant nozzle pressure ratio, the nozzle flow topology depends on the Mach number of the outer flow.

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“…They showed a reduction of the cross-pumping motion of the shear-layer by the lobes. Scharnowski et al [24] performed measurements on an axisymmetric model equipped with two passive flow control devices in the transonic flow regime. The passive flow control devices lead to reduced pressure and velocity fluctuations downstream of the base.…”

Section: Introductionmentioning

confidence: 99%

Interaction of Wake and Propulsive Jet Flow of a Generic Space Launcher

Barklage

Radespiel

2020

Notes on Numerical Fluid Mechanics and Multidisciplinary Design

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This work investigates the interaction of the afterbody flow with the propulsive jet flow on a generic space launcher equipped with two alternative nozzle concepts and different afterbody geometries. The flow phenomena are characterized by experimental measurements and numerical URANS and LES simulations. Investigations concern a configuration with a conventional truncated ideal contour nozzle and a configuration with an unconventional dual-bell nozzle. In order to attenuate the dynamic loads on the nozzle fairing, passive flow control devices at the base of the launcher main body are investigated on the configuration with TIC nozzle. The nozzle Reynolds number and the afterbody geometry are varied for the configuration with dual-bell nozzle. The results for integrated nozzles show a shift of the nozzle pressure ratio for transition from sea-level to altitude mode to significant lower levels. The afterbody geometry is varied including a reattaching and non-reattaching outer flow on the nozzle fairing. Investigations are performed at supersonic outer flow conditions with a Mach number of $$Ma_\infty =3$$. It turns out, that a reattachment of the outer flow on the nozzle fairing leads to an unstable nozzle operation.

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Passive Flow Control for the Load Reduction of Transonic Launcher Afterbodies

Cited by 5 publications

References 38 publications

Flow Separation behind an Axisymmetric After-body and Impact of Grooves at Trailing Edge

Flow Separation behind an Axisymmetric After-body and Impact of Grooves at Trailing Edge

Investigation of the base flow of a generic space launcher with dual-bell nozzle

Interaction of Wake and Propulsive Jet Flow of a Generic Space Launcher

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