Shock Train/Boundary-Layer Interaction in Rectangular Isolators

Geerts, Jonathan S.; Yu, Kenneth H.

doi:10.2514/1.j054917

Cited by 50 publications

(8 citation statements)

References 19 publications

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“…3D steady RANS equations [10] are solved for compressible flow of air, modeled as an ideal gas. The k-omega SST turbulence model [11] is used for CFD simulations.…”

Section: Governing Equations and Computational Methodologymentioning

confidence: 99%

Influence of Fluid–Thermal–Structural Interaction on Boundary Layer Flow in Rectangular Supersonic Nozzles

2018

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The aim of this work is to highlight the significance of Fluid-Thermal-Structural Interaction (FTSI) as a diagnosis of existing designs, and as a means of preliminary investigation to ensure the feasibility of new designs before conducting experimental and field tests. The novelty of this work lies in the multi-physics simulations, which are, for the first time, performed on rectangular nozzles. An existing experimental supersonic rectangular converging/diverging nozzle geometry is considered for multi-physics 3D simulations. A design that has been improved by eliminating the sharp throat is further investigated to evaluate its structural integrity at design Nozzle Pressure Ratio (NPR 3.67) and off-design (NPR 4.5) conditions. Static structural analysis is performed by unidirectional coupling of pressure loads from steady 3D Computational Fluid Dynamics (CFD) and thermal loads from steady thermal conduction simulations, such that the simulations represent the experimental set up. Structural deformation in the existing design is far less than the boundary layer thickness, because the impact of Shock wave Boundary Layer Interaction (SBLI) is not as severe. FTSI demonstrates that the discharge coefficient of the improved design is 0.99, and its structural integrity remains intact at off-design conditions. This proves the feasibility of the improved design. Although FTSI influence is shown for a nozzle, the approach can be applied to any product design cycle, or as a prelude to building prototypes.

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“…3D steady RANS equations [10] are solved for compressible flow of air, modeled as an ideal gas. The k-omega SST turbulence model [11] is used for CFD simulations.…”

Section: Governing Equations and Computational Methodologymentioning

confidence: 99%

Influence of Fluid–Thermal–Structural Interaction on Boundary Layer Flow in Rectangular Supersonic Nozzles

2018

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“…Besides the additional confinement of the duct, other influences of the sidewalls such as secondary flows, corner and sidewall separations may be important. In incident-reflected shock-boundary-layer interactions (SBLI) arrangements, these additional phenomena are thought to have a strong effect on the bulk flow near the centreline, especially in the case of highly confined ducts (Geerts & Yu, 2016a). A consistent finding on the effects of sidewall confinement is that the shock structure and general flow arrangement is highly three-dimensional (3-D), even for large aspect ratio ducts (Geerts & Yu, 2016b).…”

Section: Introductionmentioning

confidence: 99%

Numerical study of the effect of sidewalls on shock train behaviour

Gillespie

Sandham

2023

Flow

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Strongly coupled sequences of shock waves, known as shock trains, are present in high-speed propulsion systems, where the presence of sidewalls substantially modifies the boundary layer thickness, skin friction and streamwise pressure distribution. In the present contribution, scale-resolved numerical simulations are performed on supersonic channel (infinite span) and square duct flows to evaluate the effect of sidewall confinement with and without shock trains. Comparable secondary flow vortices are observed in the duct case with and without the presence of the shock train. The absence of a separation region at the leading shock of the duct case results in lower flow deflection compared with the channel case, leading to a reduced shock strength. The principal effect of the sidewalls is to cause a shock train that is approximately twice as long and composed of a larger number of shocks. A modification of previous models, based on a momentum thickness-based blockage parameter, leads to an improved collapse of the channel and duct cases.

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“…This shock system is known as a shock train and serves to decelerate the incoming supersonic flow and increase the pressure for efficient combustion. Many early studies explored the temporal mean features of the shock train, the individual shock structures and streamwise pressure variation for given inflow properties (Crocco 1958; Waltrup & Billig 1973; Ikui, Matsuo & Nagai 1974 a ; Carroll & Dutton 1990; Geerts & Yu 2016). Summarily, these studies showed that for a given back pressure, the shock trains were longer and comprised of multiple oblique shocks (‘X’ type) at high Mach numbers and confinement ratios.…”

Section: Introductionmentioning

confidence: 99%