Nonparallel effects in hypersonic boundary layer stability

Stuckert, Greg; Lin, Nay; Herbert, Thorwald

doi:10.2514/6.1995-776

Cited by 3 publications

(2 citation statements)

References 6 publications

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“…However, as Reshotko observed, the boundary layer behaves like a nonlinear oscillator and this may be a source of some discrepancy (1994). Another source of error may be the parallel flow assumption in the LST approach; Herbert et al (1993) and Stuckert and Lin (1995) noted a shift in growth rate curves when nonparallel terms are excluded.…”

Section: Linear Stability Analysismentioning

confidence: 99%

Computational Evaluation of Quiet Tunnel Hypersonic Boundary-Layer Stability Experiments

Manning

Chokani

2004

Journal of Spacecraft and Rockets

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Manning, Melissa Lynn. Computational Evaluation of Quiet Tunnel Hypersonic Boundary Layer Stability Experiments. (Under the direction of Dr. Ndaona Chokani.) A computational evaluation of two stability experiments conducted in the NASA Langley Mach 6 axisymmetric quiet nozzle test chamber facility is conducted. Navier-Stokes analysis of the mean flow and linear stability theory analysis of boundary layer disturbances is performed in the computations. The effects of adverse pressure gradient and wall cooling are examined. Calculated pressure, temperature and boundary layer thickness distributions show very good overall agreement with experimental measurements. Computed mass flux and total temperature profiles show very good quantitative agreement with uncalibrated hotwire measurements obtained with the hot-wire operated in high and low overheat modes respectively. Comparisons between calibrated hot-wire data and mean flow computations show excellent agreement in the early stages of the transitional flow. However, examination of the wire Reynolds number and mass flux and total temperature eigenfunction profiles suggest that when operated in high overheat mode the sensitivity of the hot-wire to total temperature is significant. Thus, while uncalibrated hot-wire measurements are useful to characterize the overall features of the flow, calibrated hotwire measurements are necessary for quantitative comparison with stability theory. Computations show that adverse pressure gradient and wall cooling decrease the boundary layer thickness and increase the frequency and amplification rate of the unstable second mode disturbances; these findings are consistent with the experimental observations.

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Section: Linear Stability Analysismentioning

confidence: 99%

Computational Evaluation of Quiet Tunnel Hypersonic Boundary-Layer Stability Experiments

Manning

Chokani

2004

Journal of Spacecraft and Rockets

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“…Linear stability theories predict the early stages of the amplification before the nonlinear interactions play a leading role, resulting in the breakdown towards laminar/turbulent transition. Supersonic boundary layer flows can be studied by local stability theory (LST) (Malik 1989) and parabolised stability equations (PSE) (Stuckert, Lin & Herbert 1995) for weakly non-parallel flows. For more general configurations, resolvent analyses, which also take into account the non-modal phenomena arising from the non-normality of the Navier-Stokes operator (Sipp & Marquet 2013), have become computationally affordable in the recent years.…”

Section: Introductionmentioning

confidence: 99%

Adjoint-based linear sensitivity of a supersonic boundary layer to steady wall blowing–suction/heating–cooling

Poulain,

Content,

Rigas

et al. 2024

J. Fluid Mech.

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For a Mach $4.5$ flat-plate adiabatic boundary layer, we study the sensitivity of the first, second Mack modes and streaks to steady wall-normal blowing/suction and wall heat flux. The global instabilities are characterised in frequency space with resolvent gains and their gradients with respect to wall-boundary conditions are derived through a Lagrangian-based method. The implementation is performed in the open-source high-order finite-volume code BROADCAST and algorithmic differentiation is used to access the high-order state derivatives of the discretised governing equations. For the second Mack mode, the resolvent optimal gain decreases when suction is applied upstream of Fedorov's mode $S$ /mode $F$ synchronisation point, leading to stabilisation, and the converse when applied downstream. The largest suction gradient is in the region of branch I of mode $S$ neutral curve. For heat-flux control, strong heating at the leading edge stabilises both the first and second Mack modes, the former being more sensitive to wall-temperature control. Streaks are less sensitive to any boundary control in comparison with the Mack modes. Eventually, we show that an optimal actuator consisting of a single steady heating strip located close to the leading edge manages to damp the linear growth of all three instability mechanisms.

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