On the unsteady throttling dynamics and scaling analysis in a typical hypersonic inlet–isolator flow

Sekar, K. Raja; Karthick, S. K.; Jegadheeswaran, S.; Kannan, R.

doi:10.1063/5.0032740

Cited by 58 publications

(16 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The ideal gas model was used for the calculations, and the Shear Stress Transport (SST) k-ω model was used to model the turbulence [22]. In a previous study in the literature, a RANS solver, based on the SST turbulence model in FLUENT, was successfully applied to the flow with SWBLI, and the results of this study are in good agreement with experimental results [23][24][25][26]. The viscosity coefficient follows the Sutherland formula [27].…”

Section: Methodssupporting

confidence: 57%

Control of Cowl Shock/Boundary Layer Interaction in Supersonic Inlet Based on Dynamic Vortex Generator

Wang,

Zhang

et al. 2023

Aerospace

View full text Add to dashboard Cite

A shock wave/boundary layer interaction (SWBLI) is a common phenomenon in supersonic inlet flow, which can significantly degrade the aerodynamic performance of the inlet by inducing boundary layer separation. To address this issue, in this paper, we propose the use of a dynamic vortex generator to control the SWBLI in a typical supersonic inlet. The unsteady simulation method based on dynamic grid technology was employed to verify the effectiveness of the proposed method of control and investigate its mechanism. The results showed that, in a duct of finite width at the inlet, the SWBLI generated complex three-dimensional (3D) flow structures with remarkable swirling properties. At the same time, vortex pairs were generated close to the side wall as a result of its presence, and this led to the intensification of transverse flow and, in turn, the formation of a complex 3D structure of the flow of the separation bubble. The dynamic vortex generator induced oscillations of variable intensity in the vortex system in the supersonic boundary layer that enhanced the mixing between the boundary layer flow and the mainstream. Meanwhile, the unique effects of “extrusion” and “suction” in the oscillation process continued to charge the airflow, and the distribution of velocity in the boundary layer significantly improved. As the oscillation frequency of the vortex generator increased, its charging effect on low-velocity flow in the boundary layer increased, and its control effect on the flow field of the SWBLI became more pronounced. The proposed method of control reduced the length of the separation bubble by 31.76% and increased the total pressure recovery coefficient at the inlet by 6.4% compared to the values in the absence of control.

show abstract

Section: Methodssupporting

confidence: 57%

Control of Cowl Shock/Boundary Layer Interaction in Supersonic Inlet Based on Dynamic Vortex Generator

Wang,

Zhang

et al. 2023

Aerospace

View full text Add to dashboard Cite

show abstract

“…However, as explained in the previous sections, bluff-body wake flows or separated flows, especially for two-dimensional cases, validations are scarcely available. Recently, in one of the authors' previous works, the capability of this particular solver is demonstrated in both URANS 55 and DES 56 modes at supersonic speed, where separation is encountered a lot. In line with those studies, validation is done for the bluff body flows like the v-gutters in a sub-sonic duct.…”

Section: Solver Validation In Spatial and Spectral Domainmentioning

confidence: 99%

Unsteady dynamics in a subsonic duct flow with a bluff body

George,

Karthick,

Srikrishnan

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

A series of reduced-order numerical simulations on a specific bluff body type (v-gutters) in a subsonic duct flow is done to assess the unsteady wake dynamics. Two of the v-gutter's geometrical parameters are varied: the v-gutter's base angle (θ ) and the size of a slit (ξ ) at the leading-edge of the v-gutter. Turbulent flow kinematics and pressure field are analyzed to evaluate the unsteadiness at a freestream Mach number of M ∞ = 0.25 and a freestream Reynolds number based on bluff body's transverse length (L) of Re L = 0.1 × 10 6 . Five v-gutter angles are considered (θ , • = π/6, π/4, π/3, 5π/12, π/2) and three slit sizes (ξ , mm =0,0.25,0.5) are considered only for a particular θ = [π/6]. In general, high fluctuations in velocity and pressure are seen for the bluffest body in consideration (θ = π/2) with higher drag (c d ) and total pressure loss (∆p 0 ). However, bluffer bodies produce periodic shedding structures that promote flow mixing. On the other hand, the presence of a slit on a streamlined body (θ = π/6) tends to efficiently stabilize the wake and thus, producing almost a periodic shedding structure with lower c d and ∆p 0 . For θ = [π/6], broadened spectra in vortex shedding is seen with a peak at [ f L/u ∞ ] ∼ 0.08. For θ ≥ [π/4], a dominant discrete shedding frequency is seen with a gradual spectral decay. Similarly, the effects of ξ on the θ = [π/6] case produce a discrete shedding frequency instead of a broadened one, as told before. The shedding frequency increases to a maximum of [ f L/u ∞ ] ∼ 0.26 for the maximum slit size of ξ = 0.5. From the analysis of the x − t diagram and the modal analysis of vorticity and velocity magnitude in the wake, the peaks are indeed found to agree with the spectral analysis. More insights on the shedding vortices, momentum deficit in the wake, varying energy contents in the flow field, and the dominant spatiotemporal structures are also provided.

show abstract

“…32 However, in the case of vehicles traveling at high speeds within the atmosphere, reducing aerodynamic drag is of utmost importance to enhance its range and efficiency. The spiked forebody in any form, either in missiles 33,34 or engine intakes, 35,36 reduces the overall drag as the spike creates a low pressure, recirculating, dead air region in front of the forebody. The pressure forces acting on the forebody are relatively lower than those acting on a forebody with no spike, resulting in drag reduction.…”

Section: Introductionmentioning

confidence: 99%

Unsteady pulsating flowfield over spiked axisymmetric forebody at hypersonic flows

et al. 2022

Self Cite

View full text Add to dashboard Cite

The paper gives experimental observations of the hypersonic flow past an axisymmetric flat-face cylinder with a protruding sharp-tip spike. Unsteady pressure measurements and high-speed schlieren images are performed in tandem on a hypersonic Ludwieg tunnel at a freestream Mach number of M 1 ¼ 8:16 at two different freestream Reynolds numbers based on the base body diameter (Re D ¼ 0:76 Â 10 6 and 3:05 Â 10 6 ). The obtained high-speed images are subjected further to modal analysis to understand the flow dynamics parallel to the unsteady pressure measurements. The protruding spike of length to base body diameter ratio of ½l=D ¼ 1 creates a familiar form of an unsteady flowfield called "pulsation." Pressure loading and fluctuation intensity at two different Re D cases are calculated. A maximum drop of 98.24% in the pressure loading and fluctuation intensity is observed between the high and low Re D cases. Due to the low-density field at low Re D case, almost all image analyses are done with the high Re D case. Based on the analysis, a difference in the pulsation characteristics is noticed, which arises from two vortical zones, each from a system of two "k" shocks formed during the "collapse" phase ahead of the base body. The interaction of shedding vortices from the k-shocks' triple-points, along with the rotating stationary waves, contributes to the asymmetric high-pressure loading and the observation of shock pulsation on the flat-face cylinder. The vortical interactions forming the second dominant spatial mode with a temporal mode carry a dimensionless frequency (f 2 D=u 1 % 0:34) almost twice that of the fundamental frequency (f 1 D=u 1 % 0:17). The observed frequencies are invariant irrespective of the Re D cases. However, for the high-frequency range, the spectral pressure decay is observed to follow an inverse and À7/3 law for the low and high Re D cases, respectively.

show abstract

On the unsteady throttling dynamics and scaling analysis in a typical hypersonic inlet–isolator flow

Cited by 58 publications

References 53 publications

Control of Cowl Shock/Boundary Layer Interaction in Supersonic Inlet Based on Dynamic Vortex Generator

Control of Cowl Shock/Boundary Layer Interaction in Supersonic Inlet Based on Dynamic Vortex Generator

Unsteady dynamics in a subsonic duct flow with a bluff body

Unsteady pulsating flowfield over spiked axisymmetric forebody at hypersonic flows

Contact Info

Product

Resources

About