Shock Induced Separation in Transitional Hypersonic Boundary Layers

Vanstone, Leon; Estruch-Samper, David; Hillier, R.; Ganapathisubramani, Bharathram

doi:10.2514/6.2013-2736

Cited by 18 publications

(11 citation statements)

References 10 publications

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“…Figure 1 shows establishment times for the wall pressure normalised by the analytical wave time (equation 6). Holden [1] claims that for high Mach numbers (12)(13)(14)(15)(16)(17)(18)(19)(20) the establishment times of surface pressure and heat transfer become similar; a claim which is supported by equation 10. Although, as shown later, this assumption does not appear to be true for all experiments assessed in this study.…”

Section: Previous Literaturementioning

confidence: 67%

“…Experiments show that the separation is very sensitive to the conditions of the boundary layer [15,19,20], so much so that the boundary-layer state (laminar/transitional/turbulent) can be inferred from the SWBLI shock-structure (separated/collapsed). All cases considered in this study examine the laminar boundary layer case.…”

Section: Present Studymentioning

confidence: 99%

“…A number of studies have previously examined the establishment times of separations either experimentally [1,2,3,9,10,11], numerically [7,8] or both [12,13,14,15]. A number of different methods of assessing establishment have emerged, although very few studies even discuss their establishment criteria.…”

Section: Previous Literaturementioning

confidence: 99%

“…The run averaged, steady-state laminar surface-pressure distribution for 10 different experimental runs is shown in figure 4(a) with comparison to the predicted numerical distribution. Error in measuring surface pressure is assessed as 2% [15].…”

Section: B Surface Pressure Heat-transfer and Schlieren Measurementsmentioning

confidence: 99%

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Establishment Times of Hypersonic Shock-Wave/Boundary-Layer Interactions in Intermittent Facilities

2017

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This study examines establishment times of shock-wave boundary-layer interactions across a range of interaction types and intermittent facilities. Successful design of a test-article for a short duration facility is difficult, especially when trying to guarantee establishment of the flow. While this study does not detail design methodologies of a test article it does aim to provide better understanding of establishment metrics and predictive methods that have emerged from other studies in order to help in the design and assessment of experiments. Experimental and numerical data was taken at Mach 8.9 on an axisymmetric blunt-nosed body with an eight degree flare and laminar boundary-layer. It is shown that the global applicability of any single metric is poor and hence an establishment criteria is developed for this study which provides a more global metric of establishment. Further, a framework is provided for when the use of existing establishment metrics is appropriate.

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Section: Previous Literaturementioning

confidence: 67%

Section: Present Studymentioning

confidence: 99%

Section: Previous Literaturementioning

confidence: 99%

Section: B Surface Pressure Heat-transfer and Schlieren Measurementsmentioning

confidence: 99%

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Establishment Times of Hypersonic Shock-Wave/Boundary-Layer Interactions in Intermittent Facilities

2017

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“…Generaly the flow separation is described as a kind of critical change of the flow pattern [11][12][13]. When the flow separation happens, the steady flow turns into unsteady [14,15].…”

Section: Introductionmentioning

confidence: 99%

Lengthwise finning surface as the method of influence on the flow separation in diffusers

Zaryankin¹,

Rogalev²,

Лисин³

et al. 2017

J. Appl. Math. Comput. Mech.

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Abstract. The paper deals with the analysis of power factors acting within the boundary layer for different types of flow: convergent, gradientless and diffuser. Based on the considered formation mechanism of boundary layer separation, a hypothesis about the possible influence on structure and character of a separated flow by changing the gradient of the tangential stresses in the boundary layer was proposed. This impact is proposed to realize by means of the longitudinal finning of diffuser. Verification of the concept is performed on the basis of numerical flow investigation and available experimental data.MSC 2010: 97M50

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Experiments on the effect of laminar–turbulent transition on the SWBLI in H2K at Mach 6

2015

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than two and an increase in the heat flux by a factor of more than four. Therefore, big areas of laminar flow are desirable to increase the performance of a propelled vehicle and to reduce the weight of the necessary thermal protection systems of a propelled or re-entry vehicle. On the other hand, turbulent boundary layers have a lower tendency to separate and are preferred in regions of large pressure gradients. Hence, the correct prediction of the transition is essential for the design of future hypersonic vehicles and their thermal protection systems.Shock wave-boundary layer interactions (SWBLI) are inevitable for most of the practical applications. They can cause locally increased pressure and thermal loads, cause separations and have a great influence onto the transition process. Most of the existing publications in this field deal with interactions of shock waves with turbulent boundary layers (Dupont et al. 2006; Schülein 2006;Humble et al. 2009; Helmer 2011;Grilli et al. 2012), some handle the case of interactions of shock waves with laminar boundary layers (Boin et al. 2006;Lüdeke and Sandham 2009;Brown and Boyce 2009) but investigations of the interaction between shock waves and transitional boundary layers are rare (Dolling 2001;Arnal and Delery 2004;Benay et al. 2006;Vanstone et al. 2013). In order to study these phenomena in detail within the framework of the ESA-TRP "laminar to turbulent transition in hypersonic flows," experiments in three different facilities using several measuring techniques have been carried out (Sandham et al. 2014). This paper describes the results of the experiments performed in the hypersonic wind tunnel H2K at DLR in Cologne.The transition process of undisturbed hypersonic boundary layers is most likely driven by instabilities called second (Mack) modes (Mack 1975). These are acoustic waves trapped between the wall and the sonic line. Therefore, Abstract This paper presents the results of the experiments performed in the hypersonic wind tunnel H2K in the framework of the ESA technology research project "laminar to turbulent transition in hypersonic flows". The investigations include the free boundary-layer transition on a flat plate as well as the influence of a shock wave-boundary layer interaction on the transition. The shock is created by a wedge with a small angle of attack resulting in a moderate shock intensity. The experiments were performed at Mach 6.0, at three different unit Reynolds numbers and with a translational displacement of the shock generator. Besides the optical methods-Schlieren photography and infrared thermography-several intrusive sensors were used. High-speed measurements were carried out using PCB and atomic layer thermo pile sensors. Kulite sensors were used for low-and mid-speed pressure measurements. The data analysis includes the comparison of the absolute values, the frequency spectra and wavelets and their distributions in time and space.

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Shock Induced Separation in Transitional Hypersonic Boundary Layers

Cited by 18 publications

References 10 publications

Establishment Times of Hypersonic Shock-Wave/Boundary-Layer Interactions in Intermittent Facilities

Establishment Times of Hypersonic Shock-Wave/Boundary-Layer Interactions in Intermittent Facilities

Lengthwise finning surface as the method of influence on the flow separation in diffusers

Experiments on the effect of laminar–turbulent transition on the SWBLI in H2K at Mach 6

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