Effect of microramps on flare-induced shock – boundary-layer interaction

Nilavarasan, T.; Joshi, Ganapati; Misra, Anuradha

doi:10.1017/aer.2019.138

Cited by 13 publications

(5 citation statements)

References 60 publications

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“…Thus, the separated flow was inherently three-dimensional with a flow structure that was quite similar to the one proposed by Lighthill. 87 These features are typical in many supersonic separated flows 14,63,88–92 and were first noticed and reported by Ginoux. 88,89 Several researchers have attributed these secondary effects to the presence of Gortler-like vortices.…”

Section: Resultsmentioning

confidence: 70%

“…Ability of the present computational methodology in predicting the intricate flowfield surrounding the MVGs and the flow over axisymmetric compression corners has been previously demonstrated. 63 However, additional validations were performed recently by simulating a wind tunnel experiment performed by Kuehn 12 on a cone–cylinder–flare model. Out of the many different cases analyzed by Kuehn, the one that was closest to the present study was selected (details in Table 1) for validating the computational scheme.…”

Section: Computational Methodologymentioning

confidence: 99%

“…Five different MVG shapes, namely, baseline ramp (BR), trapezoidal ramp (TZ), split ramp (SR), thick vanes (TV) and ramped vanes (RV) were used to control the interaction. The BR (Figure 4(a)) has been investigated in numerous SBLI flowfields, [55][56][57][58][59][60][61]63 and its dimensions are based on the optimization study performed by Anderson et al 60 The same study also recommended that an interdevice spacing of 7.5 h (where 'h' is the device height) be given between MVGs arranged in the form of an array, and this has been implemented for all five configurations in the present study. The trapezoidal (TZ) shape was derived from the tapered micro-vane actuators that were evaluated by Anderson et al, 60 with the difference being that the leading and trailing edges of the vanes were joined together to convert it into a wedge shaped device as shown in Figure 4(b).…”

Section: Flow Conditions and Model Detailsmentioning

confidence: 99%

“…46,47 These small scale protuberances, when placed upstream of the interaction, generate streamwise vortical structures 59 that entrain the fluid along the wall normal direction, thus creating alternate bands of upwash (low shear) and downwash (high shear) regions 60 in the incoming boundary layer. Such velocity redistributions caused three dimensional alterations [61][62][63] in the separation region and have also been shown to weaken the separation shock and increase its oscillating frequency. 64,65 Performance of these vortex generators is governed by different factors, and it goes without saying that maximum benefit can be achieved by identifying and deploying the optimum configuration.…”

Section: Introductionmentioning

confidence: 99%

“…76 Various innovative designs [77][78][79][80] have also been proposed in recent years to control shockinduced separations, but to the best of our knowledge, these different shapes have not been studied in compression corner flows. There also seems to be very few published studies 63,67,71,81 that report the effect of MVGs on axisymmetric flare-induced separations. Keeping these factors in mind, the present study focusses on evaluating the performance of five different MVG shapes, in controlling the flow separation due to a flare-induced SBLI.…”

Section: Introductionmentioning

confidence: 99%

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Performance evaluation of different micro vortex generators in controlling a flare-induced shock–boundary layer interaction

Nilavarasan

Joshi

Misra

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part G:

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This study evaluates the ability of five micro vortex generator (MVG) geometries in attenuating the flow separation induced by an axisymmetric compression corner. Experimental and computational investigations were carried out at Mach 2 on a cone–cylinder–flare model, with a flow deflection angle of 24° at the cylinder/flare juncture. The MVG shapes considered were baseline ramp, trapezoidal ramp, split ramp, thick vanes and ramped vanes. A circumferential array of these MVGs having a device height (h) of 1.4 mm and an inter-device spacing of 10.5 mm (7.5 h) was introduced 50 mm upstream of the compression corner. Streamwise counter-rotating vortex pairs that originated from these devices created alternate bands of upwash and downwash regions in the incoming boundary layer, which resulted in suitable three-dimensional alterations of the separation region’s size. Furthermore, surface streamline visualizations showed that the vortices induced profound topological transformations in the separated flow structure. In the absence of MVGs, spectral analysis of the pressure signal obtained from the separation shock’s intermittent region revealed a relatively broadband dominant frequency range of 0.55 kHz–0.9 kHz. The MVGs did not cause any significant change in the dominant frequency, but made the bandwidth slightly narrower. Among the different MVG designs that were studied, the ramped vanes (RV) induced the most momentum augmentation in the near wall region and thereby caused the maximum downstream shift in the separation shock’s position.

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