A Review of Roughness-Induced Nosetip Transition

Batt, R. G.; Legner, Hartmut H.

doi:10.2514/3.60102

Cited by 79 publications

(22 citation statements)

References 10 publications

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“…Protrusions on the surface and a spikelike morphology were more favorable for tolerating the impact of collision . Surface roughness augmented the surface reactivity and stimulated the turbulent transitions of heat flow; this led to a rise in the surface recession, which made the FS–RF nanocomposites most suitable for thermal applications. Figure shows the effect of changes in the FS content without the IL and with 2 wt % IL on the water contact angle.…”

Section: Resultsmentioning

confidence: 85%

Ionic‐liquid‐assisted three‐dimensional caged silica ablative nanocomposites

Kumar

Kandasubramanian

2017

J of Applied Polymer Sci

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In this study, we demonstrated a novel three-dimensional network of thermally stable fumed silica (FS)-resorcinol formaldehyde (RF) nanocomposites via an ionic-liquid (IL)-assisted in situ polycondensation process. The study involved subjecting the tailored nanocomposites to thermogravimetric analysis and oxyacetylene flame environment as per ASTM test standards for thermal ablative performance. X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, highresolution transmission electron microscopy, Raman spectroscopy, and wettability studies were undertaken to underline the improvement correlation in the microstructure and material properties. Significant reductions in the linear ablation rate (66%) and mass ablation rate (26.6%), along with lower back-face temperature profiles, marked enhanced ablative properties. The increased char yield (33.3%) and higher temperatures for weight losses evinced the improved thermal stability of the modified RF resin. The uniformly dispersed fused nanosilica with a glassy coating morphology on the ablative surface acted as barrier to oxidation. The results signify that the IL-assisted modification of the RF resin with FS significantly enhanced ablative performance. A viable replacement to the conventional phenolic nanocomposites for thermal ablative applications to buy critical time for the containment and suppression of thermal-heat-flux threats is of paramount importance.

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Section: Resultsmentioning

confidence: 85%

Ionic‐liquid‐assisted three‐dimensional caged silica ablative nanocomposites

Kumar

Kandasubramanian

2017

J of Applied Polymer Sci

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“…Figures 8 and 10 of Ref. 23 show, however, that the uncertainty (scatter) bands on the dependent variable (the transition parameter) in these modi ed-PANT correlations are excessivelylarge, ranging from C75 to ¡42% about the correlation t in both cases. Despite such large uncertainties, modi ed-PANT transitioncorrelations 23;26 were appliedby the reentrycommunityof the 1980s,perhapsas a result of their ease of usage;only calculations of boundary-layer edge and integral parameters were required, as opposed to the more detailed computations of smooth-wall laminar boundary-layer density, velocity, and temperature pro les required by the critical roughness Reynolds number approach.…”

Section: Nosetipsmentioning

confidence: 94%

Review and Synthesis of Roughness-Dominated Transition Correlations for Reentry Applications

Reda

2002

Journal of Spacecraft and Rockets

173

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Nomenclature a = constant; Fig. 1 C, C 0 = constants k = roughness element height, ft N k = average roughness element height, ft L = vehicle length, ft M = Mach number n = exponent; Fig. 1 N R = Poll's transition parameter 29;30 ; Eq. (1) Re ke = roughness Reynolds number based on height k and edge conditions Re kk = roughness Reynolds number based on height k and conditions at k Re µ = Reynolds number based on height µ and edge conditions U = velocity component parallel to test surface or velocity component perpendicularto attachment line, ft /s V = velocity component parallel to attachment line, ft/s X = generalized disturbance parameter or axial coordinate along windward centerline x = coordinate perpendicular to attachment line, ft Y = generalized transition parameter ® = angle of attack, deg ± = smooth-wall laminar boundary-layer thickness, ft = Poll's length scale 29;30 [Eq. (2)], ft µ = smooth-wall laminar boundary-layer momentum thickness, ft ¹ = viscosity, lbm/ft ¢ s º = kinematic viscosity, ft 2 /s ½ = density, lbm/ft 3 Subscripts al = attachment line e = edge of smooth-wall laminar boundary layer k = based on conditions in smooth-wall laminar boundary layer at top of roughness elements tr = transition w = wall or based on wall temperature Superscript ¤ = properties evaluated at Poll's reference temperature 29;30 Daniel C. Reda recently joined the Space Technology Division at NASA Ames Research Center as a Senior Scientist, responsible for aerothermodynamics research to support access-to-space and planetary-entry missions. Previously, he was a Senior Research Scientist in the Ames Research Center Fluid Mechanics Laboratory, where he developed a global surface shear stress vector measurement method using liquid crystal coatings.

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“…There are very few experimental studies that characterize the effect of isolated roughness on blunt bodies in a supersonic or hypersonic flow. [45][46][47][48][49] The publicly available information on blunt body flight transition data is summarized in Ref. 45.…”

Section: E Boundary Layer Transitionmentioning

confidence: 99%

Aerothermal Testing for Project Orion Crew Exploration Vehicle

Berry

Horvath

Lillard

et al. 2009

41st AIAA Thermophysics Conference

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The Project Orion Crew Exploration Vehicle aerothermodynamic experimentation strategy, as it relates to flight database development, is reviewed. Experimental data has been obtained to both validate the computational predictions utilized as part of the database and support the development of engineering models for issues not adequately addressed with computations. An outline is provided of the working groups formed to address the key deficiencies in data and knowledge for blunt reentry vehicles. The facilities utilized to address these deficiencies are reviewed, along with some of the important results obtained thus far. For smooth wall comparisons of computational convective heating predictions against experimental data from several facilities, confidence was gained with the use of algebraic turbulence model solutions as part of the database.For cavities and protuberances, experimental data is being used for screening various designs, plus providing support to the development of engineering models. With the reaction-control system testing, experimental data were acquired on the surface in combination with off-body flow visualization of the jet plumes and interactions. These results are being compared against predictions for improved understanding of aftbody thermal environments and uncertainties.

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A Review of Roughness-Induced Nosetip Transition

Cited by 79 publications

References 10 publications

Ionic‐liquid‐assisted three‐dimensional caged silica ablative nanocomposites

Ionic‐liquid‐assisted three‐dimensional caged silica ablative nanocomposites

Review and Synthesis of Roughness-Dominated Transition Correlations for Reentry Applications

Aerothermal Testing for Project Orion Crew Exploration Vehicle

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