Boundary-layer transition was studied on a sharp 7 deg cone in two hypersonic wind tunnels at Mach numbers of 5, 6, 8, and 14 over range freestream Reynolds between 3.3 . High-speed schlieren measurements visualized the intermittent formation instabilities turbulent spots within transitional boundary layer. Surface pressure heat-transfer revealed how behavior layer produces mean character these quantities. Transition 5 appeared to be initiated by combination first- second-mode instabilities....

The size of a pressure transducer is known to affect the accuracy measurements wall-pressure fluctuations beneath turbulent boundary layer because spatial averaging over sensing area transducer. In this paper, effect finite investigated by applying or wavenumber filters database hypersonic wall generated from direct numerical simulation (DNS) that simulates portion sharp 7° half-angle cone at nominally Mach 8. A good comparison between DNS and experiment in Sandia Hypersonic Wind Tunnel 8...

During atmospheric reentry, hypersonic vehicles are subjected to high levels of boundarylayer pressure ∞uctuations. To improve understanding and prediction these ∞uctuations, measurements surface ∞uctuations on a 7 ‐ sharp cone were conducted in Sandia’s Hypersonic Wind Tunnel under noisy ∞ow Purdue University’s Boeing/AFOSR Mach-6 Quiet quiet ∞ow. Fluctuations laminar boundary layers re∞ected tunnel noise levels. Laminar boundary-layer an order magnitude lower than Transition the model only...

Abstract To investigate the pressure-fluctuation field beneath turbulent spots in a hypersonic boundary layer, study was conducted on nozzle wall of Boeing/AFOSR Mach-6 Quiet Tunnel. Controlled disturbances were created by pulsed-glow perturbations based electrical breakdown air. Under quiet-flow conditions, nozzle-wall layer remains laminar and grows very thick over long length. This allows development large that can be well-resolved with high-frequency pressure transducers. A disturbance...

Although low-disturbance ("quiet") hypersonic wind tunnels are believed to provide more reliable extrapolation of boundary-layer transition behavior from ground flight, the presently available quiet facilities limited Mach 6, moderate Reynolds numbers, low freestream enthalpy, and subscale models. As a result, only conventional ("noisy") can reproduce both numbers enthalpies flight configurations must therefore be used for vehicle test evaluation involving high number, larger This paper...

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This research effort coordinated by the NATO Science and Technology Organization Applied Vehicle 240 specialists' group compiles analyzes second-mode amplitudes on sharp slender cones. The analysis focuses pressure fluctuations measured with piezoelectric sensors in 11 hypersonic wind tunnels operated nine organizations located three countries (Belgium, Germany, United States) Japan. measurements are at freestream Mach numbers between 5 14, unit Reynolds 1.5 , wall-to-total temperature...

Experiments were performed to understand the complex fluid-structure interactions that occur during aircraft internal store carriage. A cylindrical was installed in a rectangular cavity having length-to-depth ratio of 3.33 and length-to-width 1. The Mach number ranged from 0.6 2.5 incoming boundary layer turbulent. Fast-response pressure measurements provided aeroacoustic loading cavity, while triaxial accelerometers simultaneous response. Despite occupying only 6% volume, significantly...

The effects of freestream noise on roughness-induced transition were measured for the HIFiRE forecone model. Temperature-sensitive paint measurements used to visualize wake roughness elements under quiet and noisy flow. Reynolds number increased flow, a less-than-effective trip, by factor up 6.4 when referenced trip location. difference in location between flow conditions is significantly reduced effective trips are used, but still delays an trip. STABL calculations over model at 0 6 angle...

Abstract : Experiments were carried out in the Boeing/AFOSR Mach 6 Quiet Tunnel at Purdue University and Sandia National Laboratories Hypersonic Wind 5 8. The purpose was to measure second-mode boundary-layer instabilities on a 7 deg half-angle cone zero angle of attack using surface pressure sensors. Second-mode waves successfully measured all three numbers, including under both noisy quiet conditions. most amplified disturbance frequencies compared well linear Parabolized Stability...

The development of turbulent spots in a hypersonic boundary layer was studied on the nozzle wall Boeing/AFOSR Mach-6 Quiet Tunnel. Under quiet flow conditions, remains laminar and grows very thick over long length. This allows large that can be readily measured with pressure transducers. Measurements naturally occurring wave packets developing were made. peak frequencies these natural agreement second-mode computations. For controlled study, breakdown disturbances created by spark glow...

The influence of compressibility on the shear layer over a rectangular cavity variable width has been studied in free stream Mach number range 0.6–2.5 using particle image velocimetry data streamwise centre plane. As increases, vertical component turbulence intensity diminishes modestly widest cavity, but two narrower cavities show more substantial drop all three components as well turbulent stress. This contrasts with canonical layers, which significant reductions only and stress due to...

Fluid–structure interactions due to intermittent turbulent spots were studied on a 7 deg half-angle cone in the Sandia Hypersonic Wind Tunnel at Mach 5 and 8 Purdue Boeing/U.S. Air Force Office of Scientific Research 6 Quiet Tunnel. A thin composite panel was integrated into response boundary-layer disturbances characterized by accelerometers backside panel. Under quiet flow conditions 6, boundary layer remained laminar. Artificially generated excited directionally dependent response. When...

This experimental work explores the flow field around a three-dimensional expansion–compression geometry on slender cone at Mach 8 using high-frequency pressure sensors, high-frame-rate schlieren, temperature-sensitive paint, shear-stress measurements and oil-flow visualizations. The $7^\circ$ has hyperbolic slice which acts as an expansion corner suppresses disturbances present in upstream boundary layer. Downstream of cone-slice corner, boundary-layer attenuate all cases. Under laminar...

Fluid–structure interactions that occur during aircraft internal store carriage were experimentally explored at Mach 0.58–1.47 using a generic, aerodynamic installed in rectangular cavity having length-to-depth ratio of seven. The vibrated response to the flow its natural structural frequencies, and it exhibited directionally dependent resonance frequencies. Cavity tones excited streamwise wall-normal directions consistently, whereas spanwise was much more limited. Increased surface area...

The flow over an aircraft bay is often represented using a rectangular cavity; however, this simplification neglects many features of actual flight geometry that could affect the unsteady pressure field and resulting loading in bay. To address shortcoming, complex cavity was developed to incorporate more realistic aircraft-bay including shaped inlets, internal structure, doors. A parametric study these conducted based on fluctuating measurements at subsonic supersonic Mach numbers. Resonance...

The paper presents an investigation of fluid–thermal–structural interaction (FTSI) on a complex geometry in hypersonic flows. objective is to assess high-fidelity numerical tools for FTSI by validating two frameworks against wind-tunnel data. We choose cone–slice–ramp with wedge angle 30 deg subjected laminar inflow at Mach 8. First, the time-averaged and time-resolved flow solutions are validated highlight mean features their unsteady characteristics, including low-frequency bubble...

A high-speed schlieren system was developed for the Sandia Hypersonic Wind Tunnel. Schlieren images were captured at 290 kHz and used to study growth breakdown of second-mode instabilities into turbulent spots on a 7 ◦ cone. At Mach 5, wave packets would intermittently occur break down isolated surrounded by an otherwise smooth, laminar boundary layer. 8, layer dominated which larger regions turbulence. Second-mode waves these patches as opposed smooth flow seen 5. Detailed pressure...

High-frequency pressure sensors were used in conjunction with a high-speed schlieren system to study the growth and breakdown of boundary-layer disturbances into turbulent spots on 7 cone Sandia Hypersonic Wind Tunnel at Mach 5 8. To relate intermittent average characteristics transition cone, statistical distribution these must be known. These include boundarylayer intermittency, burst rate, disturbance length. Traditional low-speed methods characterize intermittency identify only...

High-frequency pressure sensors were used in conjunction with a high-speed schlieren system to study the growth and breakdown of boundary-layer disturbances into turbulent spots on 7◦ cone Sandia Hypersonic Wind Tunnel. At Mach 5, intermittent low-frequency observed videos. secondmode wave packets would develop within these break down isolated surrounded by an otherwise smooth, laminar boundary layer. Spanwise measurements showed that have narrow spanwise extent before they down. The...