Measurements and Computations of Second-Mode Instability Waves in Several Hypersonic Wind Tunnels

Berridge, Dennis C.; Casper, Katya M.; Rufer, Shann J.; Alba, Christopher R.; Lewis, Daniel R.; Beresh, Steven J.; Schneider, Steven P.

doi:10.2514/6.2010-5002

Cited by 24 publications

(11 citation statements)

References 25 publications

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“…Its frequency depends on the path length and the unit Reynolds number and is between 70 and 200 kHz. Consistent with the results on cones, the frequency at the same path length increases with an increasing unit Reynolds number and decreases with an increasing path length for the same unit Reynolds number (Berridge et al 2010;. The amplification of the amplitude in the transition region and the destruction of the second (Mack) mode towards the end of the transition can also be confirmed.…”

Section: Averaged Frequency Spectrasupporting

confidence: 85%

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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Section: Averaged Frequency Spectrasupporting

confidence: 85%

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

2015

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“…Numerous efforts 1,4,6,9,12,18,23,25,28,29,[30][31][32][33][34][35] have provided insight into the stability and transition of such systems, though as a testimony to the complexity of the problem, considerable uncertainty still exists. Other 3-D geometries such as the elliptic cone have also provided insight 18,[36][37][38][39][40][41][42][43] .…”

Section: Geometrymentioning

confidence: 99%

Instabilities on a Hypersonic Yawed Straight Cone

Pérez

Reed

Kuehl

2013

43rd Fluid Dynamics Conference

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Our current activities focus on providing linear and nonlinear parabolized stability equation analysis of the hypersonic crossflow and second-mode instability over a 7˚-halfangle yawed straight cone. A study is conducted to complement the experiments at Mach 6 in the Hypersonic Ludwieg Tube at Braunschweig 1 . Multiple instabilities can be simultaneously present in a 3-D boundary layer. For azimuthal angle 70° and x=0.36 m, analysis following Mack 2 suggests that the low-frequency disturbances observed are related to traveling crossflow. Simultaneously, a second mode is predicted with frequency range well predicted by LPSE.

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“…Pitot probe measurements of freestream noise will be completed in late 2011 and compared to the pressure fluctuations measured in the model boundary layer. Similar work was presented at the 2010 Fluid Dynamics Conference in Chicago, IL 16 from experiments at Langley's 15-Inch Mach 6 and 31-Inch Mach 10 Tunnels as well as the AEDC Tunnel 9 facility; this paper is an extension of that work.…”

Section: Introductionmentioning

confidence: 61%

“…Saturation amplitudes have previously been observed to vary from as low as 5% at Mach 5 to as much as 30% at Mach 10. 16 The main determinant of the saturation amplitude is unknown. Figure 6(b) shows RMS amplitudes of the second-mode waves with the blunt nosetip installed.…”

Section: American Institute Of Aeronautics and Astronauticsmentioning

confidence: 99%

“…The cone model was previously tested, under similar conditions, in both the Langley 15-Inch Mach 6 tunnel 16 and the Boeing/AFOSR Mach 6 Quiet Tunnel at Purdue University run under both noisy and quiet conditions 8 . Figure 10 shows PCB data from the same axial location on the cone in each of these tunnels for Re/m ≈ 10x10 6 .…”

Section: E Preliminary Tunnel-to-tunnel Comparisonmentioning

confidence: 99%

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