Topological interpretation of the surface flow visualization of conical viscous/inviscid interactions

Oudheusden, B.W. van; Nebbeling, C.; Bannink, W.J.

doi:10.1017/s0022112096000468

Cited by 10 publications

(9 citation statements)

References 13 publications

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“…Panaras (1996) reviewed the work of Kubota & Stollery (1982) and Alvi & Settles (1992); analysis has been provided by van Oudheusden, Nebbeling & Bannink (1996). The fin is a wedge that is mounted on a sidewall.…”

Section: Previous Related Sbli Researchmentioning

confidence: 99%

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Shock wave–boundary layer interactions in rectangular inlets: three-dimensional separation topology and critical points

Eagle

Driscoll

2014

J. Fluid Mech.

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The interaction between two separated flow regions was studied for the fundamental problem of a shock wave-boundary layer interaction (SBLI) within a rectangular inlet. One motivation is that the inlet of an engine on a supersonic aircraft may contain separation zones on the sidewalls and the bottom wall; if one region separates first it can alter the flow on the other wall and lead to engine unstart. In our work an oblique shock wave was generated by a wedge suspended from the upper wall of a Mach 2.75 wind tunnel. Stereo particle image velocimetry (PIV) measurements were recorded in 25 planes that include all three possible orthogonal orientations. The lateral velocity and vorticity measurements help to explain the underlying flow structure and these quantities were not measured previously for this problem. It is concluded that the sidewall and bottom wall separation zones interact due to an underlying flow structure that is similar to the two types of 3-D separation patterns previously described by Tobak & Peake (Annu. Rev. Fluid Mech., vol. 14, 1982, pp. 61-85). Separation first occurs at an upstream location where the shock interacts with the sidewall. Lateral velocities direct flow toward the centreline to cause separation on the bottom wall. This causes significant curvature of the shock wave, so that even the region near the tunnel centreline cannot be explained by conventional 2-D concepts. A number of critical points (saddle points, nodes, focus points) were identified. Results are consistent with the general ideas of Burton & Babinsky (J. Fluid Mech., vol. 707, 2012, pp. 287-306) and help to provide details of how the sidewalls redistribute the adverse pressure gradient in space.

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Section: Previous Related Sbli Researchmentioning

confidence: 99%

“…In steady, laminar, incompressible flows, it has been shown that limiting streamlines are identical to skin friction lines and oil streak lines (van Oudheusden et al 1996). Squire (1961) has demonstrated that oil film lines are accurate markers of the skin friction lines in steady flows.…”

Section: Brief Review Of Critical Point Theorymentioning

confidence: 99%

Shock wave–boundary layer interactions in rectangular inlets: three-dimensional separation topology and critical points

Eagle

Driscoll

2014

J. Fluid Mech.

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“…This flow field is characterised by the separation line, upstream influence and reattachment line. 9 This fin induced flow has been found to have a dominant effect on the flow studied at present. The flow topology of the interaction similar to the present condition is given by Eagle et.al.…”

Section: Figure 1 Typical Shock-wave Boundary Layer Interaction Nearmentioning

confidence: 80%

Experimental investigation of a Mach 4 shock-wave turbulent boundary layer interaction near an expansion corner

SathiaNarayanan

Verma

2015

53rd AIAA Aerospace Sciences Meeting

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Experimental investigation has been carried out to study the interaction between incident shock-wave and turbulent boundary layer near an expansion corner at a free stream Mach number of 3.9. The wedge angle (α), expansion angle (β) and the distance of inviscid impingement location (X) from the expansion corner were varied. Fin induced vortex dominated side wall flow was found to affect the complex interaction and make the interaction three dimensional which otherwise would be two dimensional. The line of separation is found to be independent of expansion corner angle even for the impingement downstream of expansion corner. With increase in wedge angle, the line of separation moves upstream. Peak pressure reduces with downstream impingement location and increase in expansion corner angle. Pressure far downstream of the interaction region is found to be nearly same irrespective of the configurations.

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“…A typical schematic of surface flow from flow visualization experiments is shown in Fig.2. The surface flow pattern formed by a sharp fin is conical(Lu, 1993;Settles and Dolling, 1992;Oudheusden et al, 1996), and not cylindrical(Johnston, 1960;Myring, 1977;Knight et al, 1992;Van Oudheusden et al, 1996). The topological pattern of the surface streamlines in conical interactions has been interpreted recently by Van Oudheusden et al(1996).In Fig.2, the schematic surface pattern depicts a geometric conicity, in that rays are shown emanating from a certain origin close to the fin apex.…”

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confidence: 81%

“…As a result, this convergence line is formed before it becomes parallel to the shock as the shock wave angle increases. Van Oudheusden et al (1996) argued that the far field of the conical interaction does not possess a quasi-two dimensional structure in the cross-flow plane of the radial direction. They showed that the conicity of the inviscid flow regions in supersonic flow produces a geometrically conical surface flow pattern.…”

Section: Physical Mechanism For Incipient Separationmentioning

confidence: 99%

Incipient separation in shock wave/boundary layer interactions as induced by sharp fin

2006

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The incipient separation induced by the shock wave/ turbulent boundary layer interaction at the sharp fin is the subject of present study. Existing theories for the prediction of incipient separation, such as those put forward by McCabe (1966) and Dou and Deng (1992), can have thus far only predicting the direction of surface streamline and tend to over-predict the incipient separation condition based on the Stanbrook's criterion. In this paper, the incipient separation is firstly predicted with Dou and Deng (1992)'s theory and then compared with ' experimental data. The physical mechanism of the incipient separation as induced by the shock wave/turbulent boundary layer interactions at sharp fin is explained via the surface flow pattern analysis.Furthermore, the reason for the observed discrepancy between the predicted and experimental incipient separation conditions is clarified. It is found that when the wall limiting streamlines behind the shock wave becomes aligning with one ray from the virtual origin as the strength of shock wave increases, the incipient separation line is formed at which the wall limiting streamline becomes perpen- Knight et al., 2003). However, the cost of a full Navier-Stokes calculation is still fairly exorbitant, especially for 3D flows. In addition, issues relating to the accuracy from a physical point of view (besides the numerical accuracy) for purpose of quantitative comparison to experiments and the elucidation of the complex physical flow are not always satisfactory. Therefore, some analytical work like the simple predictive methods is still imperative for an initial estimate of the main flow physics based on preliminary design and then for progress to the subsequent stages leading eventually to the final prototype. To try to do a thorough simulation at the preliminary design stage is just too costly and most probably ineffective.In the past over 30 years or so, there are limited works carried out on the separation behaviour in SW/TBLI induced by a sharp fin on a flat plate as typified by Fig. 1 (Bogdonoff, 1987;Delery and Marvin, 1986;Green, 1970;Panaras, 1996;Settles and Dolling, 1992;Neumann and Hayes, 2002). As the onset or occurrence of flow separation invariably changes the topology of the flow field, one important and critical problem to resolve is how to judge or predict the incipient separation and its underlying flow physics. A typical topology of the surface flow pattern is shown schematically in outside the boundary layer. This analysis appears to have more fundamental physical basis than those by McCabe (1966), Korkegi (1973), or Lu (1989. Their results also show the trend of α i decreasing with increasing Re θ which had been previously discussed in Lu (1993) and Leung and Squire (1995). It may be noted that Leung and Squire's (1995) experimental data confirmed the same trend for α i versus Re θ as in Dou and Deng's theory. Furthermore, McCabe (1966) and Dou and Deng (1992c) found that the incipient separation angle α i via skin-friction line (also called ...

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Topological interpretation of the surface flow visualization of conical viscous/inviscid interactions

Cited by 10 publications

References 13 publications

Shock wave–boundary layer interactions in rectangular inlets: three-dimensional separation topology and critical points

Shock wave–boundary layer interactions in rectangular inlets: three-dimensional separation topology and critical points

Experimental investigation of a Mach 4 shock-wave turbulent boundary layer interaction near an expansion corner

Incipient separation in shock wave/boundary layer interactions as induced by sharp fin

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