Receptivity of a supersonic boundary layer over a flat plate. Part 1. Wave structures and interactions

Ma, Yanbao; Zhong, Xiaolin

doi:10.1017/s0022112003004786

Cited by 232 publications

(227 citation statements)

References 34 publications

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“…For the Reynolds number of his example, this additional viscous solution is damped, and it is analogous to the Mode F mentioned in prior sections. We would like to point out that [MZ03a,MZ03b] and [ZM02] refer to Mode F as Mode I and refer to Mode S, not as a single family, but rather to the parts that comprise the family (Mack's first mode, second mode, etc. ).…”

Section: Discussionmentioning

confidence: 99%

Theoretical and Computational Studies of Stability, Transition and Flow Control in High-Speed Flows

Tumin¹

2008

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Public Reporting burden for this collection of information is estimated to average I hour per response. including the time for reviewing instructions, searching existing data sources. gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comment regarding this burden estimates or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services. Directorate for information Operations and Reports. 1215 AFOSR /t0P(f North Randolph Street AFRL-SR-AR-TR-08-0144Suite 325, Room 3112 Arlington, VA 2299 3-1768 I1. SUPPLEMENTARY NOTESThe views, opinions and/or findings contained in this report are those of the author(s) and should not be construed as an official Department of the Army position, policy or decision, unless so designated by other documentation. Approved for public release; distribution unlimited. ABSTRACT (Maximum 200 words)A comprehensive study of stability and receptivity of hypersonic boundary layers has been carried out. The main results of the project: 1. Mathematical method of the multimode decomposition for three-dimensional perturbations in compressible boundary layers has been developed. The method provides analysis of experimental and computational results for modes of discrete and continuous spectra. 2. Theory of boundary-layer receptivity was developed for roughness-induced perturbations in incompressible and compressible boundary layers. 3. The transient growth phenomenon in compressible boundary layers over flat plate, sphere, and sharp cone has been studied. The work was accompanied by development of solvers for these geometries. IntroductionThe potential of sustained hypersonic flight to revolutionize military and commercial activity is well recognized, and is reflected in recent initiatives such as the National Aerospace Initiative. High-speed vehicles will substantially impact military strategy by providing new defensive options such as a rapid on-demand global strike capability with much shorter response times than currently possible. Furthermore, the development of new technologies based on air-breathing propulsion can be leveraged to considerably reduce the cost of accessto-space, the benefits of which are both military as well as commercial. However, daunting technical challenges remain in realizing such vehicles. The harsh environment imposed by the envelope of such future missions is manifested in the severe anticipated thermo-mechanical loads and various propulsion-related requirements. Although the diversity of the physical phenomena encountered is broad, several key limiting issues have been identified as primary challenges, including both local and global constraints such as, for example, cowl lip loading and airframe balance. A scrutiny of the problems identified reveals the pervasive importance of several basic fluid dynamic phenomena. One of these, and possibly the least understood, is that of high-speed transition.The impact of hypersonic boundary lay...

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Section: Discussionmentioning

confidence: 99%

Theoretical and Computational Studies of Stability, Transition and Flow Control in High-Speed Flows

Tumin¹

2008

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“…Direct numerical simulations (DNS) of receptivity of a flat-plat boundary layer were conducted by Ma & Zhong (2003a,b, 2005 and Balakumar (2003Balakumar ( , 2005. These simulations, in which shocks are present and accounted for, show that in the presence of free-stream acoustic, vortical and entropy disturbances, first and second modes are excited.…”

Section: Introductionmentioning

confidence: 99%

Response and receptivity of the hypersonic boundary layer past a wedge to free-stream acoustic, vortical and entropy disturbances

Qin

2016

J. Fluid Mech.

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This paper analyses the response and receptivity of the hypersonic boundary layer over a wedge to free-stream disturbances including acoustic, vortical and entropy fluctuations. Due to the presence of an attached oblique shock, the boundary layer is known to support viscous instability modes whose eigenfunctions are oscillatory in the far field. These modes acquire a triple-deck structure. Any of three elementary types of disturbances with frequency and wavelength on the triple-deck scales interacts with the shock to generate a slow acoustic perturbation, which is reflected between the shock and the wall. Through this induced acoustic perturbation, vortical and entropy free-stream disturbances drive significant velocity and temperature fluctuations within the boundary layer, which is impossible when the shock is absent. A quasi-resonance was identified, due to which the boundary layer exhibits a strong response to a continuum of high-frequency disturbances within a narrow band of streamwise wavenumbers. Most importantly, in the vicinity of the lower-branch neutral curve the slow acoustic perturbation induced by a disturbance of suitable frequency and wavenumbers is in exact resonance with a neutral eigen mode. As a result, the latter can be generated directly by each of three types of free-stream disturbances without involving any surface roughness element. The amplitude of the instability mode is determined by analysing the disturbance evolution through the resonant region. The fluctuation associated with the eigen mode turns out to be much stronger than free-stream disturbances due to the resonant nature of excitation and in the case of acoustic disturbances, to the well-known amplification effect of a strong shock. Moreover, excitation at the neutral position means that the instability mode grows immediately without undergoing any decay, or missing any portion of the unstable region. All these indicate that this new mechanism is particularly efficient. The boundary-layer response and coupling coefficients are calculated for typical values of parameters.

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“…Our understanding of different instability mechanisms, and of different transition processes in shear layers, have greatly improved in the last several decades. [1][2][3][4][5][6][7][8] Transition-prediction methods, however, have not made much progress 9 . The main difficulty is due to the nature of the transition process itself, which depends on the boundary layer characteristics and on the frequency and wave number distributions of the disturbances that enter the boundary layer.…”

Section: Introductionmentioning

confidence: 99%

Receptivity of Hypersonic Boundary Layers over Straight and Flared Cones

Balakumar

Kegerise

2015

AIAA Journal

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The effects of adverse pressure gradients on the receptivity and stability of hypersonic boundary layers were numerically investigated. Simulations were performed for boundary layer flows over a straight cone and two flared cones. The steady and the unsteady flow fields were obtained by solving the twodimensional Navier-Stokes equations in axi-symmetric coordinates using the 5 th -order accurate weighted essentially non-oscillatory (WENO) scheme for space discretization and using third-order total-variation-diminishing (TVD) Runge-Kutta scheme for time integration. The mean boundary layer profiles were analyzed using local stability and non-local parabolized stability equations (PSE) methods. After the most amplified disturbances were identified, two-dimensional plane acoustic waves were introduced at the outer boundary of the computational domain and time accurate simulations were performed. The adverse pressure gradient was found to affect the boundary layer stability in two important ways. Firstly, the frequency of the most amplified second-mode disturbance was increased relative to the zero pressure gradient case. Secondly, the amplification of first-and second-mode disturbances was increased. Although an adverse pressure gradient enhances instability wave growth rates, small nose-tip bluntness was found to delay transition due to the low receptivity coefficient and the resulting weak initial amplitude of the instability waves. The computed and measured amplitudefrequency spectrums in all three cases agree very well in terms of frequency and the shape except for the amplitude.

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Receptivity of a supersonic boundary layer over a flat plate. Part 1. Wave structures and interactions

Cited by 232 publications

References 34 publications

Theoretical and Computational Studies of Stability, Transition and Flow Control in High-Speed Flows

Theoretical and Computational Studies of Stability, Transition and Flow Control in High-Speed Flows

Response and receptivity of the hypersonic boundary layer past a wedge to free-stream acoustic, vortical and entropy disturbances

Receptivity of Hypersonic Boundary Layers over Straight and Flared Cones

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