https://engineering.purdue.edu/~aae519/BAM6QT-Mach-6-tunnel/reviewpapers/cone-scram-blt-review-pas-feb04.pdf

Hypersonic laminar–turbulent transition on circular cones and scramjet forebodies

It is well known that the high levels of noise present in conventional hypersonic ground-test facilities cause transition to occur earlier than in e ight. Flight measurements of incoming noise are reviewed and compared with measurements in ground-test facilities, of both conventional and quiet design, at hypersonic and high supersonic speeds. The low noise present in e ight is apparently the reason for the very large transition Reynolds numbers sometimes measured in e ight, when roughness, crosse ow, and other factors are controlled. Design will usually involve consideration of the trend in transition when a parameter is varied. The effect of facility noise on these trends is reviewed. In some cases, the trend of conventional-tunnel data is opposite to the trend in quiet-tunnel data. Thus, transition measurements in conventional ground-test facilities are not reliable predictors of e ight performance, except perhaps in special cases.

Effects of High-Speed Tunnel Noise on Laminar-Turbulent Transition

This paper reviews the state of phosphor thermometry, focusing on developments in the past 15 years. The fundamental principles and theory are presented, and the various spectral and temporal modes, including the lifetime decay, rise time and intensity ratio, are discussed. The entire phosphor measurement system, including relative advantages to conventional methods, choice of phosphors, bonding techniques, excitation sources and emission detection, is reviewed. Special attention is given to issues that may arise at high temperatures. A number of recent developments and applications are surveyed, with examples including: measurements in engines, hypersonic wind tunnel experiments, pyrolysis studies and droplet/spray/gas temperature determination. They show the technique is flexible and successful in measuring temperatures where conventional methods may prove to be unsuitable.

https://www.mdpi.com/1424-8220/8/9/5673/pdf

Thermographic Phosphors for High Temperature Measurements: Principles, Current State of the Art and Recent Applications

The effect of roughness on hypersonic boundarylayer transition has been studied for three primary purposes: to trip a laminar layer to turbulence, to determine whether naturally occurring roughness is expected to cause early transition, and to determine the largest allowable roughness that will not affect the location of transition. Roughness is often divided into two classes: isolated roughness in which each protuberance can be considered separately, and distributed roughness similar to sandpaper, in which the roughness elements are many and are not considered separately. The effects of roughness on hypersonic transition are reviewed, considering the physics of the process, known parametric effects, some of the common correlations, and a few case studies. The three or more modes by which roughness can affect transition are outlined. At hypersonic edge Mach nunbers, it requires very large roughness heights to affect transition. Various correlations are often used to estimate the effect of roughness; several of these are described, although none provide good agreement with all the data.

Effects of Roughness on Hypersonic Boundary-Layer Transition

The challenges in understanding hypersonic flight are discussed and critical hypersonic aerothermodynamics issues are reviewed. The ability of current analytical methods, numerical methods, ground testing capabilities, and flight testing approaches to predict hypersonic flow are evaluated. The areas where aerothermodynamic shortcomings restrict our ability to design and analyze hypersonic vehicles are discussed, and prospects for future capabilities are reviewed. Considerable work still needs to be done before our understanding of hypersonic flow will allow for the accurate prediction of vehicle flight characteristics throughout the flight envelope from launch to orbital insertion.

/pdf/critical-hypersonic-aerothermodynamic-phenomena-ahf6pytiml.pdf

Critical Hypersonic Aerothermodynamic Phenomena

Boundary-layer trip devices for the Hyper-X forebody have been experimentally examined in several wind tunnels.Fivedifferenttripconegurationswerecomparedinthreehypersonicfacilities:theNASALangleyResearch Center 20-Inch Mach 6 Air and 31-Inch Mach 10 Air tunnels and in the HYPULSE Reeected Shock Tunnel at the General Applied Sciences Laboratory. Heat-transfer distributions, utilizing the phosphor thermography and thin-elm techniques, shock system details, and surface streamline patterns were measured on a 0.333-scale model of the Hyper-X forebody. Parametric variations include angles of attack of 0, 2, and 4 deg; Reynolds numbers based on model length of 1.2 ££ 10 6‐15.4 £ 10 6 ; and inlet cowl door simulated in both open and closed positions. Comparisons of boundary-layer transition as a result of discrete roughness elements have led to the selection of a trip coneguration for the Hyper-X Mach 7 eight vehicle.

/pdf/hypersonic-boundary-layer-trip-development-for-hyper-x-1typxzigf3.pdf

Hypersonic Boundary-Layer Trip Development for Hyper-X

Boundary layer trip devices for the Hper-X forebody have been experimentally examined in several wind tunnels. Five different trip configurations were compared in three hypersonic facilities, the LaRC 20-Inch Mach 6 Air Tunnel, the LaRC 31 -Inch Mach 10 Air Tunnel, and in the HYPULSE Reflected Shock Tunnel at GASL. Heat transfer distributions, utilizing the phosphor thermography and thin-film techniques, shock system details, and surface streamline patterns were measured on a 0.333-scale model of the Hyper-X forebody. Parametric variations include angles-of-attack of 0-deg, 2-deg, and 4-deg; Reynolds numbers based on model length of 1.2 to 15.4 million: and inlet cowl door simulated in both open and closed positions. Comparisons of transition due to discrete roughness elements have led to the selection of a trip configuration for the Hyper-X Mach 7 flight vehicle.

/pdf/hypersonic-boundary-layer-trip-development-for-hyper-x-4iohs764hx.pdf

John F. Calleja

Papers

Hypersonic Boundary-Layer Trip Development for Hyper-X

Hypersonic Boundary-Layer Trip Development for Hyper-X