Stabilization of hypersonic boundary layers by porous coatings

Федоров, А. В.; Malmuth, N.; Rasheed, Adam; Hornung, H. G.

doi:10.2514/6.2001-891

Cited by 37 publications

(75 citation statements)

References 12 publications

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“…This uncertainty varied from shot to shot, but it ranged from §3 to §15%, depending on the slope of the transitional t. When the additional uncertainty due to density ( §8%), velocity ( §4%) and viscosity ( §5%) were factored in, the overall uncertainty in transition Reynolds number ranged from §11 to §19%, with a median of §13%. Figures 4c and 4d show that the boundary layer on the smooth surface transitions well upstream as comparedto the poroussurfaceand appearsto validatethe prediction by Fedorov et al 10 Once again, the Germain and Hornung 1 data for a similar run condition is shown for comparison with excellent agreement as to the transition location. In this particular case, the smooth surface boundary layer transitions roughly at the halfway point on the cone whereas the poroussheet boundarylayer is laminar all of the way to the end of the cone.…”

supporting

confidence: 82%

“…Because of the nature of the laser drilling process, the holes were slightly conical (taper angle of about 0.5-deg) with the small diameter exposed to the ow. The thickness of the sheet (thus, the depth of the holes) was 450 ¹m (26 gauge sheet) and followed the Fedorov et al 10 analysis that the depth of the holes be approximately 30% of the boundary-layer displacement thickness. The porous surface began at approximately148 mm from the tip of the cone as per the Fedorov et al analysis 10 using the lower branch of the neutral stability curve for the Mack mode at a frequency of 1 MHz.…”

Section: Porous Sheetmentioning

confidence: 98%

“…Note that the proposed control mechanism is purely passive and that there is no net ow (suction or blowing) through the holes. This paper will discuss the details of the experiments performed in the T5 Hypervelocity Shock Tunnel to test the computational prediction by Fedorov et al 10 that suitable wall porosity delays transition in hypersonic boundary layers.…”

Section: Introduction Hmentioning

confidence: 99%

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Experiments on Passive Hypervelocity Boundary-Layer Control Using an Ultrasonically Absorptive Surface

et al. 2002

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Recently performed linear stability analyses suggested that transition could be delayed in hypersonic boundary layers by using an ultrasonically absorptive surface to damp the second mode (Mack mode). Boundary-layer transition experiments were performed on a sharp 5.06-deg half-angle round cone at zero angle of attack in the T5 Hypervelocity Shock Tunnel to test this concept. The cone was constructed with a smooth surface around half the cone circumference (to serve as a control) and an acoustically absorptive porous surface on the other half. Test gases investigated included nitrogen and carbon dioxide at M 1 ' 5 with speci c reservoir enthalpy ranging from 1.3 to 13.0 MJ/kg and reservoir pressure ranging from 9.0 to 50.0 MPa. Comparisons were performed to ensure that previous results obtained in similar experiments (on a regular smooth surface) were reproduced, and the results were extended to examine the effects of the porous surface. These experiments indicated that the porous surface was highly effective in delaying transition provided that the pore size was signi cantly smaller than the viscous length scale.

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supporting

confidence: 82%

Section: Porous Sheetmentioning

confidence: 98%

Section: Introduction Hmentioning

confidence: 99%

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Experiments on Passive Hypervelocity Boundary-Layer Control Using an Ultrasonically Absorptive Surface

et al. 2002

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“…Fedorov et al have shown that the thermal admittance B has a marginal e¨ect [12]. It is consequently neglected in the present work.…”

Section: Linear Stability Theorymentioning

confidence: 92%

Direct numerical simulations of mack-mode damping on porous coated cones

Lüdeke¹,

Wartemann²

2013

Progress in Flight Physics

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The §ow ¦eld over a 3 degree blunt cone is investigated with respect to a hypersonic stability analysis of the boundary-layer §ow at Mach 6 with porous as well as smooth walls by comparing local direct numerical simulations (DNS) and linear stability theory (LST) data. The original boundary-layer pro¦le is generated by a ¦nite volume solver, using shock capturing techniques to generate an axisymmetric §ow ¦eld. Local boundary-layer pro¦les are extracted from this §ow ¦eld and hypersonic Mack-modes are superimposed for cone-walls with and without a porous surface used as a passive transition-reduction device. Special care is taken of curvature e¨ects of the wall on the mode development over smooth and porous walls.

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“…The understanding of this phenomenon is of great importance because receptivity connects the amplitude of the free-stream disturbances and initial amplitude of the unstable waves 9 . Recent experimental [9][10][11][12][13] , theoretical [14][15][16][17][18][19] and computational [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] studies increased our understanding about receptivity mechanism. However it still remains as a challenging problem with practical importance.…”

Section: Introductionmentioning

confidence: 99%

Effects of Wall Cooling on Hypersonic Boundary Layer Receptivity over a Cone

Kara

Balakumar

Kandil

2008

38th Fluid Dynamics Conference and Exhibit

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E ffects of wall cooling on the receptivity process induced by the interaction of slow acoustic disturbances in the free-stream are numerically investigated for a boundary layer flow over a 5-degrees straight cone. T he free-stream M ach number is 6.0 and the Reynolds number is 7.8x10 6 /ft. Both the steady and unsteady solutions are obtained by solving the full Navier-Stokes equations using 5 th -order accurate weighted essentially non-oscillatory (W E N O) scheme for space discretization and using 3 rd -order total variation diminishing (T V D) Runge-K utta scheme for time integration. Computations are performed for a cone with nose radius of 0.001 inch for adiabatic wall temperature (T aw ), 0.75*T aw , 0.5*T aw , 0.40*T aw , 0.30*T aw , and 0.20*T aw . O nce the mean flow field is computed, disturbances are introduced at the upstream end of the computational domain. Generation of instability waves from leading edge region and receptivity of boundary layer to slow acoustic waves are investigated. Computations showed that wall cooling has strong stabilization effect on the first mode disturbances as was observed in the experiments. T ransition location moved to upstream when wall cooling was applied It is also found that the boundary layer is much more receptive to fast acoustic wave (by almost a factor of 50). W hen simulations performed using the same forcing frequency growth of the second mode disturbances are delayed with wall cooling and they attained values two times higher than that of adiabatic case. In 0.20*T aw case the transition Reynolds number is doubled compared to adiabatic conditions. T he receptivity coefficient for adiabatic wall case (804 °R) is 1.5225 and for highly cooled cones (241, and 161 °R); they are in the order of 10 -3 .

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Stabilization of hypersonic boundary layers by porous coatings

Cited by 37 publications

References 12 publications

Experiments on Passive Hypervelocity Boundary-Layer Control Using an Ultrasonically Absorptive Surface

Experiments on Passive Hypervelocity Boundary-Layer Control Using an Ultrasonically Absorptive Surface

Direct numerical simulations of mack-mode damping on porous coated cones

Effects of Wall Cooling on Hypersonic Boundary Layer Receptivity over a Cone

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